RU2497234C2 - Photoelectric conversion element, photoelectric conversion device and image reading system - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: photoelectric conversion element for making a light path to said photoelectric conversion portion includes a middle portion and a peripheral portion having a refraction index different from that of the middle portion, within a certain plane parallel to the light-receiving surface of the photoelectric conversion portion, and within another plane lying closer to the light-receiving surface than said certain plane, and parallel to the light-receiving surface, wherein the peripheral portion is continuous with the middle portion and surrounds the middle portion; the refraction index of the peripheral portion is greater than that of the insulating film and the thickness of the peripheral portion within said other plane is smaller than that of the peripheral portion within said certain plane.

EFFECT: high sensitivity of photoelectric conversion elements with high efficiency of using incident light.

28 cl, 11 dwg

Description

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION

This invention relates to a photovoltaic conversion device having a light guide path configuration.

Description of the Related Art

In the case of a photoelectric conversion device including numerous photoelectric conversion elements, in order to increase the number of photoelectric conversion sections and / or reduce the dimensions of the photoelectric conversion device, it is necessary to reduce the width of the light receiving surface. Accordingly, the sensitivity of the photoelectric conversion elements themselves may be reduced. Therefore, sensitivity can be increased by increasing the efficiency of the use of incident light.

An effective measure to increase the efficiency of using incident light is to provide a light guide path to the light receiving surface of the photoelectric converting element (light receiving section), as described in Japanese Patent Laid-Open No. 2008-166677.

Summary of the invention

In a first embodiment of the present invention, there is provided a photoelectric conversion element including a photoelectric conversion section and a light path creating element deposited on a photoelectric conversion section and surrounded by an insulating film, wherein the light path creating element includes a first section and a second section, having the same stoichiometric composition as the first portion, and also having a higher refractive index than the refractive index of the first section, the second section is made inextricably with the first section and surrounds the first section, and in addition, the refractive index of the first section is greater than the refractive index of the insulating film, within a plane parallel to the light receiving surface of the photoelectric conversion section, and within another plane, parallel to the light receiving surface and being closer to the light receiving surface than said certain plane, and wherein the thickness of the second portion within said other th plane is smaller than the thickness of the second portion within said certain plane.

In a second embodiment of the present invention, there is provided a photovoltaic conversion element including a photovoltaic conversion section and a light path element applied to the photovoltaic conversion section and surrounded by an insulating film, wherein the insulating film includes a first insulating layer and a second insulating layer of silicon oxide or silicate glass, the element for creating a light path includes a first section and a second section having a higher refractive index than the refractive index of the first section, while the second section is continuous with the first section and surrounds the first section, and in addition, the refractive index of the second section is greater than the refractive index of the insulating film, within a plane parallel to the light-receiving surface of the photoelectric section transformations, and within a different plane parallel to the light-receiving surface and closer to the light-receiving surface than the mentioned plane besides, the thickness of the second section within said other plane is less than the thickness of the second section within said certain plane.

Additional features of the present invention will become apparent from the following description of possible embodiments with reference to the accompanying drawings.

Brief Description of the Drawings

In FIG. 1 is a schematic cross-sectional drawing for describing an example of a photoelectric conversion element.

In FIG. 2 (including FIG. 2A and FIG. 2B) is a schematic cross-sectional view of a portion of a photoelectric conversion element for describing an example of a first embodiment.

In FIG. 3 (including FIG. 3A and FIG. 3B) is a schematic drawing for describing a first embodiment.

In FIG. 4 (including FIG. 4A and FIG. 4B) is a schematic cross-sectional view of a portion of a photoelectric conversion element for describing an example of a second embodiment.

In FIG. 5 (including FIG. 5A and FIG. 5B) is a schematic cross-sectional diagram of a portion of a photoelectric conversion element for describing an example of a third embodiment.

In FIG. 6 (including FIG. 6A and FIG. 6B) is a schematic cross-sectional view of a portion of a photoelectric conversion element for describing an example of a fourth embodiment.

In FIG. 7 (including FIG. 7A and FIG. 7B) is a schematic cross-sectional diagram of a portion of a photoelectric conversion element for describing an example of a fifth embodiment.

In FIG. 8 (including FIG. 8A and FIG. 8B) is a schematic cross-sectional view of a portion of a photoelectric conversion element for describing an example of a sixth embodiment.

In FIG. 9 (including FIG. 9A and FIG. 9B) is a schematic cross-sectional view of a portion of a photoelectric conversion element for describing an example of a seventh embodiment.

In FIG. 10 is a schematic drawing for describing a seventh embodiment.

In FIG. 11 is a schematic drawing for describing an example of a photoelectric conversion device and an image reading system.

Description of Embodiments

First, with reference to FIG. 1, an overview of a photovoltaic conversion element will be given. In FIG. 1 is a schematic cross-sectional drawing showing an example of a photoelectric conversion element.

The photoelectric conversion element 1 includes a photoelectric conversion section 110. Numerous photovoltaic converting elements 1 are arranged in the form of a one-dimensional or two-dimensional formation, constituting a photovoltaic converting device. A photovoltaic conversion device will be described below with reference to FIG. 11, but the photoelectric conversion device may further include a peripheral circuit for controlling signals received from the photoelectric conversion elements 1.

A photoelectric conversion section 110 is applied to the substrate 100. In the photoelectric conversion device in question, a single substrate 100 includes multiple photoelectric conversion sections 110, and each of the multiple photoelectric conversion sections 110 is part of a separate photoelectric conversion element 1.

In connection with the photoelectric conversion section 110, it is noted that the upper side surface in the drawing is a light receiving surface 111. The imaginary (geometric) plane including the light receiving surface 111 will be referred to as the first plane 1001. Typically, the photoelectric conversion section 110 is formed by introducing the impurity into a deeper section than the main surface 101 of the semiconductor substrate 100. Therefore, as a rule, the light receiving surface 111 of the photocell section 110 ktricheskogo convert substantially matches at least a portion of the major surface 101 of the substrate 100, and a first plane 1001 includes a main surface 101 of the substrate 100.

However, by imparting a cavity to the main surface 101 of the semiconductor substrate 100, the photoelectric conversion section 110 can be formed in a deeper section than the bottom surface of this cavity. Alternatively, a thin film can be formed on the main surface of a glass plate or similar means having a configuration of the "metal - dielectric - semiconductor" (MIS) structure type. In these cases, the main surface 101 of the substrate 100 and the light receiving surface 111 of the photoelectric conversion section 110 are not always within the same plane.

At least an insulating film 200 is deposited on the substrate 100 (on the main surface 101), which covers one main surface 101, where the photoelectric conversion section 110 of the substrate 100 is located. That is, the bottom surface of the insulating film 200 is in contact with the main surface 101 substrates 100. In the case of the example shown in FIG. 1, an insulating film 200 covers the main surface 101 of the substrate 100 and the light receiving surface 111 of the photoelectric conversion section 110. The insulating film 200 has insulating properties to such an extent that the plurality of photoelectric conversion sections 110 are not electrically conductive (have lower electrical conductivity than the electrical conductivity of the substrate 100). Generally, the insulating film 200 is transparent. The insulating film 200 may be a single-layer film consisting of a single material, but, as a rule, the insulating film 200 is a multilayer film in which numerous layers are composed of mutually different materials.

An example of an insulating film 200 in the case of a multilayer film will now be described. If there is an insulating film 200, in the order shown below from the side of the main surface 101, the first insulating layer 205, the second insulating layer 206, the third insulating layer 207, the fourth insulating layer 208, the fifth insulating layer 209, the sixth insulating layer 210, the seventh insulating layer are sequentially laid 211, the eighth insulating layer 212, the ninth insulating layer 213, the tenth insulating layer 214 and the eleventh insulating layer 215. The insulating film 200 also includes a twelfth insulating layer 216 located between the second part o insulating layer 206 and part of the third insulating layer 207.

Of these insulating layers, the second insulating layer 206, the fifth insulating layer 209, the seventh insulating layer 211, the ninth insulating layer 213 and the eleventh insulating layer 215 are made of silicon oxide (SiO ₂ ). The third insulating layer 207 is made of borophosphosilicate glass (BFSS), but can be made of phosphosilicate glass (FSS) or borosilicate glass (BSS) or silicon oxide (SiO ₂ ) instead of BFSS. Of these insulating layers, the first insulating layer 205, the fourth insulating layer 208, the eighth insulating layer 212, the tenth insulating layer 214 and the twelfth insulating layer 216 are made of silicon nitride (Si ₃ N ₄ ).

Wiring 217 may be routed to the inner portion of the insulating film 200. Wiring 217 may be multilayer wiring. FIG. 1 illustrates an example in which wiring 217 is made of a first wiring layer 2171, a second wiring layer 2172, and a plug layer 2173. A plug layer 2173 is located between the first wiring layer 2171 and the second wiring layer 2172 and connects the first wiring layer 2171 to the second wiring layer 2172. Although an example is shown in which the number of wiring layers is two, three or more wiring layers can be provided, further depositing a wiring layer between the first wiring layer 2171 and the second wiring layer 2172. As the wiring material, an electrically conductive material such as copper, aluminum, tungsten, tantalum, titanium, polycrystalline silicon or the like can be used. Typical electrical wiring 217 is opaque and has a metallic sheen. On the main surface 101 of the semiconductor substrate 110, a gate valve 218 of a transfer valve having a metal-oxide-semiconductor (MOS) structure configuration is applied. The gate electrode 218 is made of polycrystalline silicon and is connected to the first wiring layer 2171 via a plug not shown.

An example will now be shown regarding wiring 217. A plug not shown can be formed by forming a single moire pattern using tungsten as the main component. The first wiring layer 2171 may be formed by the method of forming a single moire pattern using copper as the main component. The plug layer 2173 and the second wiring layer 2172 can be integrally formed by forming a double moire pattern using copper as the main component. In this case, the fourth insulating layer 208, the sixth insulating layer 210 and the eighth insulating layer 212 can be used as an etching control layer and a layer where copper is absent, and the tenth insulating layer 214 can be used as a layer where copper is absent. Note that the first wiring layer 2171, the second wiring layer 2172, the contact layer 2173 and the plug may have a protective metal near the interface with the insulating film 200 and tantalum as the main component.

The insulating film 200 has an opening portion 201 (hole section). Although the portion of the opening may consist of a through hole or portion of the recess, FIG. 1 illustrates a configuration in the case where the opening portion 201 consists of a recessing portion. The insulating film 200 is essentially flat and has an upper surface 202 parallel to the main surface 101 of the substrate 100. Here, the eleventh insulating layer 215 forms the upper surface 202 of the insulating film 200. An imaginary (geometric) plane including the upper surface 202 will be referred to as the second plane 1002. The second plane 1002 is parallel to the first plane 1001, and the first plane 1001 and the second plane 1002 are separated essentially due to the thickness of the insulating film 200. Section 201 of the aperture is made inextricably with henna surface 202. In more detail, the opening portion 201 consists of a bottom surface and a side surface 204. Here, the twelfth insulating layer 216 forms a bottom surface 203. The imaginary (geometric) plane including the bottom surface 203 will be referred to as the third plane 1003. The bottom surface 203 is located in the region corresponding to the light receiving surface 111. In more detail, the bottom surface 203 is located so that it falls onto the orthogonal projection from the light receiving surface 111 in a direction parallel to the main surface 101 (a direction parallel to the first plane 1001 of the third plane 1003). Thus, the light receiving surface 111 of the bottom surface 203 faces each other through a portion of the insulating film 200. The third plane 1003 is parallel to the second plane 1002 (and the first plane 1001), and the second plane 1002 and the third plane 1003 are separated essentially due to the depth of the section 201 openings. The lateral surface 204 is made inextricably with the upper surface 202 and the bottom surface 203. Accordingly, the side surface 204 essentially extends between the second plane 1002 and the third plane 1003. Note that the cross-sectional shape of the opening portion 201 will be U-shaped, and the boundary between the bottom surface 203 and the side plane may not actually be explicit pronounced. Even so, the third plane 1003 includes at least a point closest to the substrate 100 on the surface on the side opposite to that side of the insulating film 200 where the substrate 100 is (i.e., opposite to the bottom of the opening portion 201). As described above, the surface of the insulating film 200 on the side opposite to that of the substrate 100 has an upper surface 202, a bottom surface 203 and a side surface 204. The surface of the insulating film 200 on the side where the substrate 100 is, is the bottom surface of the insulating film 200 As can be seen from the above description, the distance between the first plane 1001 and the third plane 1003 is essentially equivalent to the difference between the thickness of the insulating film 200 and the depth of the opening portion 201.

In one embodiment, the depth of the opening portion 201 is one quarter of the thickness of the insulating film 200 or more, and may be half the thickness of the insulating film 200 or more. Furthermore, the depth of the opening portion 201 is greater than the wavelength of the incident light. A typical incident wavelength is 0.55 μm for green light, and the distance D is equal to or greater than 0.55 μm. Accordingly, the thickness of the insulating film 200 exceeds 0.55 μm. The thickness of the insulating film 200 may be equal to or greater than 1.0 μm. Excessively thickening of the insulating film 200 increases the mechanical stress or takes longer to produce, and therefore the thickness Tz of the insulating film 200 is substantially equal to or less than 1.0 μm, and may also not exceed 5.0 μm.

The flat sectional shape of the side surface 204 of the opening portion 201 (the shape of the opening portion 201 within a plane parallel to the first plane 1001) is a closed loop shape and may have a circular shape, elliptical shape, rounded rectangular shape, rectangular shape or hexagonal shape. In this case, the flat sectional shape of the side surface 204 of the opening portion 201 has a circular shape. Note that the bottom surface 203 also has a circular shape. The width (diameter) of the opening edge of the opening portion 201 (lateral surface 204 within the second plane 1002) is typically equal to or less than 10 μm, and may also not exceed 5.0 μm. This invention demonstrates a distinct advantage in the case when the width of the edge of the opening is equal to or less than 2.0 microns.

The cross-sectional shape of the opening portion 201 (the shape of the opening portion 201 within a plane perpendicular to the first plane 2001 passing through the median axis) may have the shape of an inverted trapezoid, an isosceles trapezoid shape, a rectangle shape, a square shape, or a layered shape that is a combination of these shapes.

An element 220 for creating a light path is located inside the opening portion 201. So that light can pass through the element 220 to create a light path, this element 220 to create a light path is made transparent. Note that the term “transparent” as used here may refer to wavelength selectivity to the extent that the requirement of sufficient transparency with respect to light is satisfied, essentially, in the wavelength band providing photovoltaic conversion.

Since the light path element 220 is located on the inner side of the opening portion 201, the light path element 220 is located above the photoelectric conversion section 110 and is surrounded by an insulating film 200. In more detail, the light path element 220 is surrounded by a side surface 204 of the portion 201 the opening and is in contact with the side surface 204 of the insulating film 200. In addition, the light path element 220 is also in contact with the bottom surface 203 of the portion 201 p oema. In addition, in more detail, the light path element 220 is surrounded by a third insulating layer 207, a fourth insulating layer 208, a fifth insulating layer 209, a sixth insulating layer 210, a seventh insulating layer 211, an eighth insulating layer 212, and a ninth insulating layer 213. the tenth insulating layer 214 and the eleventh insulating layer 215 of the insulating film 200. Then, the light path element 220 is in contact with the twelfth insulating layer 216 forming the bottom surface 203 of the opening portion 201. Thus, the light path element 220 is located in a region corresponding to a photoelectric conversion section 110 (an orthogonal projection region of the light receiving surface 111). Note that in the case where a through hole is adopted as the opening section 201 instead of the recess section, the light receiving surface 111 forms the bottom surface 203 of the opening section 201. In other words, the light path element 220 is in contact with the photoelectric conversion section 110. The depth of the opening portion 201 is substantially equal to the thickness of the insulating film 200.

The shape of the light path element 220 is generally consistent with the shape of the opening portion 201. In this embodiment, the light path element 220 has a truncated cone shape, but may have a truncated pyramid shape, a prism shape, or a cylindrical shape corresponding to the shape of the opening portion 201. The light path element 220 has a shape having axial symmetry about the median axis. The width (diameter) of the element 220 for creating the light path, as a rule, is equal to or less than 10 microns, and may not exceed 5.0 microns. This invention demonstrates a distinct advantage in the case when the width of the edge of the opening is equal to or less than 2.0 microns.

The refractive index of at least a portion of the light path element 220 is greater than the refractive index of the insulating film 200. Note that in the following description, the refractive index of the insulating film 200 will be described as the refractive index of the material that makes up most of the insulating film 200. the refraction part of the element 220 to create a light path may be equal to or less than the refractive index of the insulating film. In the case of simply mentioning the refractive index in connection with this invention, this means that we are talking about the absolute refractive index. Although the refractive indices differ depending on wavelengths, the refractive index referred to herein is a refractive index at least at a wavelength of light that can generate a signal charge in the photoelectric conversion section 110. In addition, in the case where the photoelectric converting elements 1 have a wavelength selection portion, such as a color filter or the like, the wavelength of light transmitted by this wavelength selection portion is applied. However, for practical purposes, the wavelength of incident light can be considered as corresponding to 0.55 μm — the wavelength of green light to which human eyes are sensitive, and in the following description the refractive index will be described as the refractive index corresponding to a wavelength of 0.55 μm.

If the refractive index of the outer layer of the light path element 220 is greater than the refractive index of the insulating film 200, and the light path element 220 and the insulating film 200 form an interface, total internal reflection is optically and geometrically at this interface, which directs the incident light to the element 220 to create a light path and, therefore, can direct it to the light receiving surface 111.

Note that such a configuration is known, which is a configuration of the light guide path, in the presence of which an opaque film is provided between the light path element and the side surface to prevent the light path element from coming into contact with the insulating film (see, for example, Patent Laid-Open Japan No. 2002-118245). If an opaque film is provided, it is possible to reduce the amount of light that leaks from the side surface 204, which causes scattered light radiation. In addition, if the opaque film is a film having a metallic luster (metal film or a similar film), reflection from the metal occurs in this opaque film, and therefore, incident light can be directed to the light receiving surface inside the element to create a light path. However, when an opaque film is positioned between the light path element 220 and the side surface 204, light that does not enter the light path element 220 but enters the insulating film 200 is noticeably worse used since this light did not enter into the element 220 to create a light path. On the other hand, if an opaque ribbon is not provided, then when the light path element 220 is in contact with the side surface 204 of the insulating film 200, light entering the insulating film 200 will enter the insulating film 200 into the 220 element creating a light path, as a result of which it is possible to increase the efficiency of light use.

The material (transparent material) of the light path element 220 may be an organic material or an inorganic material. However, inorganic materials are desirable since inorganic materials are chemically stable. Examples of resins include a resin based on a siloxane system and polyimide or similar resins. Suitable inorganic materials are silicon nitride (Si ₃ N ₄ ), silicon oxynitride (SiO _x N _y ) and titanium oxide (TiO ₂ ). The light path element 220 may be made of a single material or may be made of several materials. Below, approximate values of the refractive indices of those materials that are given as examples of the materials of the element 220 for creating the light path and the insulating film 200 will be mentioned. These values are 1.4-1.5 for silicon oxide, 1.6-1.9 for oxynitride silicon, 1.8-2.3 for silicon nitride, 2.5-2.7 for titanium oxide and 1.4-1.6 for borosilicate glass, phosphosilicate glass and borophosphosilicate glass (BSS, FSS and BFSS). Note that the significant digits of the refractive index values mentioned here are two digits, and the second decimal digit after the decimal point is discarded as a result of rounding. The above values are only an example, and even in the case of the same materials, the ratio of the components of non-stoichiometric composition or density of the material changes due to a change in the method of film formation, as a result of which the refractive index can be properly set. Note that the refractive index of a conventional resin is 1.3 - 1.6, and even a resin with a high refractive index has a corresponding value of 1.6-1.8, and the effective refractive index can be increased by introducing a high inorganic material into the resin refraction, such as metal oxide or the like. Examples of high refractive index inorganic materials introduced into the resin include titanium oxide, tantalum oxide, niobium oxide, tungsten oxide, zirconium oxide, zinc oxide, indium oxide and hafnium oxidation, or the like.

Although the details with respect to the embodiment will be described below, it is still noted that in the present invention, the light path element 220 has refractive index distributions that are formed by a first high refractive index region and a second high refractive index region having a higher refractive index than the refraction of the first region of a high refractive index. This refractive index distribution is formed within the region (middle region and peripheral region) occupied by the same material as constituting at least part of the light path element 220. In practice, the refractive index of the element 220 to create the light path is equal to or greater than 1.6. In addition, in practice, the difference between the maximum value and the minimum value of the refractive indices in the distribution of refractive indices characteristic of the area occupied by the aforementioned one material is equal to or greater than 0.025, and may be equal to or greater than 0.050. Note that, as a rule, the difference between the maximum value and the minimum value of refractive indices is equal to or less than 0.50, and practically equal to or less than 0.25. With such a distribution of the refractive index, the boundary between the first region of the high refractive index and the second region of the high refractive index may or may not be clearly observable. For example, if the refractive index changes smoothly from the central axis to the insulating film 200, then the boundary between the first region of the high refractive index and the second region of the high refractive index will not be clearly observed. In this case, the boundary between the first region of the high refractive index and the second region of the high refractive index can be determined as follows. In particular, an intermediate value is obtained between the maximum value and the minimum value of the refractive indices of a portion made of the same material within the element 220 to create a light path (i.e., (maximum value + minimum value) / 2). With this distribution of the refractive index within the light path element 220, the line connecting the point serving as this intermediate value can be defined as the boundary between the first region of the high refractive index and the second region of the high refractive index. Needless to say, the first region of the high refractive index includes a portion whose refractive index is minimal, and the second region of the high refractive index includes a portion whose maximum refractive index.

Note that the term “same (same) material” means materials having the same stoichiometric composition. Accordingly, a material whose composition differs from stoichiometric (i.e., having a different, non-stoichiometric composition), and a material whose crystallinity, material density, inclusion density (lower than that of the main material), impurity material (whose concentration is equal to or less than 1 wt.%) and the density of the impurities are different, can be called one and the same material. For example, although the ratio of the components of the stoichiometric composition of silicon nitride is Si: N = 3: 4, materials whose actual ratios between Si and N are mutually different within the range where the ratios of the components of the stoichiometric composition are the same can be considered the same material . In addition, for example, monocrystalline silicon and polysilicon (polycrystalline silicon) are considered as the same material. Note that materials having a different stoichiometric composition are not the same material. For example, although both titanium monoxide (TiO) and titanium dioxide (TiO ₂ ) are oxide and titanium compounds (i.e., titanium oxide), these materials are stoichiometrically different. As described above, silicon nitride has a significantly higher refractive index than the refractive index of silicon oxide, and also has a wider range of available refractive index than silicon oxynitride, and therefore is suitable as a material having the above refractive index distribution. In the case of using silicon nitride as the light path element 220, the above refractive index distributions can be formed by changing the method of forming silicon nitride film during film formation. In addition, in the case of using a resin in which the metal oxide particles are dispersed to form the light path element 220, the aforementioned refractive index distributions can also be formed by varying the density of the high refractive index inorganic material introduced into the resin. Although the distribution of the refractive index in the light path element 220 can be formed using materials that are different from each other, this invention shows a distinct advantage in the case where the distribution of the refractive index in the light path element 220 is formed using the same material as described above.

The method of forming the element 220 to create the light path and the insulating film 200 is not limited to any particular method. As a rule, you can apply the first method of formation, in the implementation of which - after the formation of the insulating film 200 having a section 201 of the opening, due to the fact that the insulating film that does not have a section 201 of the opening is subjected to etching, the material of the element 220 to create a light path besieged on the section 201 of the opening, thereby forming an element 220 to create a light path. In addition, you can apply the second method of formation, in which the process of providing the opening is repeated due to the fact that the insulating layers are etched each time that each insulating layer constituting the insulating film 200 is formed and the deposition process of the material of the element 220 is carried out to create a light path in the opening. In addition, you can apply the third method of formation, in the implementation of which - after the previous placement of the element 220 to create the light path - place part of the insulating layers of the insulating film 200 around the element 220 to create the light path. You can also apply the fourth method of formation, in the implementation of which - after forming an insulating film that does not have a portion 201 of the opening, improve the part of the insulating film corresponding to the element 220 to create the light path, thereby forming the element 220 to create the light path.

Regarding the example of FIG. 1, an example is shown here in which the first formation method is applied. The twelfth insulating layer 216 forms part of the insulating film 200 and forms the bottom surface 203 of the opening portion 201. The twelfth insulating layer 216 is located on the upper portion of the light receiving surface 111 and on the upper portion of the portion of the gate electrode 218. The area of the twelfth insulating layer 216 in the plane direction is larger than the bottom surface area 203. The area of the twelfth insulating layer 216 in the plane direction is smaller than the area of the first insulating layer 205 and the second insulating layer 206. In this case, the bottom surface 203 of the opening portion 201 is in the range where the third insulating layer 207 exists. In other words, the third insulating layer 207 located within the third plane 1003. The bottom surface of the opening portion 201 (third plane 1003) may be closer to the semiconductor substrate 100 than the first wiring layer 2171.

The twelfth insulating layer 216 can serve as a means of stopping the etching during the formation of the opening portion 201 in the multilayer insulating film 200. In order for the twelfth insulating layer 216 to serve as the means of stopping the etching, a material different from the layer that is in contact with the upper surface is used the twelfth insulating layer 216 (in this case, it is the material of the third insulating layer 207 made of BFSS). FIG. 1 illustrates a mode in which — during the formation of the opening portion 201 — as a result of the twelfth insulating layer 216 being subjected to some etching, the bottom surface 203 is closer to the side of the photoelectric conversion section 110 than the upper surface of the twelfth insulating layer 216. As a result, , the twelfth insulating layer 216 forms a small portion of the side surface 204 located closer to the bottom surface 203. The twelfth insulating layer 216, serving as a means of stopping the etching, may not be subjected to etching at all, in which case the twelfth insulating layer 216 forms only the bottom surface 203.

If a layer is provided between the second insulating layer 206 and the photoelectric conversion section 110 (in this case, the first insulating layer 205 made of silicon nitride) having a refractive index between the refractive index of the second insulating layer 206 and the refractive index of the photoelectric conversion section 110, the transmission from the light path element 220 to the photoelectric conversion section 110 is improved.

As described above, at least the light path element 220 and the insulating film 200 have a light guide path configuration, and the light entering the photoelectric conversion element 1 extends in principle to the photoelectric conversion section 110 through the light path element 220. A transparent film 319 is provided above the light path element 220 and the insulating film 200A.

On the side of the light-receiving surface 111, which is opposite to the transparent film 319, in the following order from the side of the transparent film 319, a second layer 320 with an average refractive index, a layer 321 with a low refractive index, a first layer 322 with an average refractive index, a second layer 323 a lens substrate, a second lens body layer 324, a second lens body coating layer 325, a flattened film 326, a color filter layer 327, a first lens substrate layer 328 and a first lens body layer 329. Although the details of these layers will be described below, we note that, without introducing restrictions on this configuration, it is possible to implement its various modifications. For example, at least one of the first layer 329 of the lens body (and the first layer 328 of the lens substrate) and the second layer 324 of the lens body (and the second layer 323 of the lens substrate) can be excluded. If the second layer 324 of the lens body (and the second layer 323 of the lens substrate) is eliminated, the flattened film 326 can also be eliminated. In addition, the color filter layer 327 can be excluded, or it is possible that the color filter layer 327 also serves as a flattened film films 326.

The transparent film 319 controls the distance (the path of light) from the outer surface of the photoelectric conversion element 1 (in this case, from the surface of the first layer 329 of the lens body) to the insulating film 200 and the light path element 220. A typical thickness of the transparent film 319 is equal to or greater than 0.080 microns. On the other hand, with excessive thickening of the transparent film 319, the amount of light incident on the light path element 220 is reduced. The thickness of the transparent film 319 is equal to or less than the depth of the opening portion 201, and may also not exceed half the depth of the opening portion 201. A typical thickness of the transparent film 319 is equal to or less than 0.50 μm.

Although the material of the transparent film 319 may differ from the material of the element 220 to create the light path, it is desirable that both of them be the same material. If the material of the transparent film 319 and the material of the element 220 to create the light path are the same, the element 220 to create the light path and the transparent film 319 are made as a whole, and therefore the boundary between the element 220 to create the light path and the transparent film 319 may not be distinctly observable. As described above, the light path element 220 is located on the inner side of the opening portion 201 (between the second plane 1002 and the third plane 1003), and the transparent film 319 is located on the outside of the opening portion 201. Accordingly, the light path element 220 and the transparent film 319 can be distinguished by determining whether there is transparent material on the inside of the opening portion 201 or on the outside of the opening portion 201. The distinction between the inner side and the outer side of the opening portion 201 can be achieved by imaginarily extending the top surface 202 of the insulating film 200 upward above the opening portion 201 (the upper edges of the side surface 204 are imaginary connected by a straight line) by means of the observed cross-sectional image of the photoelectric conversion element 1.

The foregoing description is made in the context of a general understanding of the photovoltaic conversion elements 1. Next, with reference to FIG. 2-10, an embodiment of the distribution of the refractive index, which is characteristic of the light path element 220, will be described. Note that in FIG. 2 and 4-9 only the substrate 100 shown in FIG. 1, a portion from a first plane 1001 to a second plane 1002 and a transparent film 319. Regarding the areas above the transparent film 319, we note that their configuration is normal and can also be changed accordingly, so their description will be omitted. In addition, in these figures, an element or portion having the same function is denoted by the same reference numeral, and a detailed description thereof will be omitted.

First Embodiment

In FIG. 2A is a cross-sectional drawing in a direction perpendicular to the main surface 101 (and the light receiving surface 111) of the portion of the photoelectric conversion element 1 in accordance with the first embodiment, and FIG. 2B is a cross-sectional drawing in a direction parallel to the main surface 101 (and the light receiving surface 111) of the portion of the photoelectric conversion element 1 in accordance with the first embodiment.

In addition to the first plane 1001, the second plane 1002, and the third plane 1003 described with reference to FIG. 1, in FIG. 2A shows a fourth plane 1004, a fifth plane 1005 and a sixth plane 1006. The fourth plane 1004 is located between the second plane 1002 and the third plane 1003 and is a plane that is at the same distance from the second plane 1002 and the third plane 1003. That is, the fourth plane 1004 is located in the middle between the second plane 1002 and the third plane 1003. The fifth plane 1005 is located between the second plane 1002 and the fourth plane 1004, and the sixth plane 1006 is located between the third plane 1003 and the fourth plane 1004. That is, the fifth plane 1005 is a plane that represents the upper portion of the light path element 220 (half the input side) and, for convenience, is taken in this case as a plane at the same distance from the second plane 1002 and the fourth plane 1004 Similarly, the sixth plane 1006 is a plane representing the lower portion of the light path element 220 (half the output side) and, for convenience, is taken in this case as a plane, finding I am at the same distance from the third plane 1003 and the fourth plane 1004.

View S1 in FIG. 2B illustrates a cross-section in a second plane 1002, view S2 illustrates a cross-section in a fifth plane 1005, view S3 illustrates a cross-section in a fourth plane 1004, and view S4 illustrates a cross-section in a sixth plane 1006. View S5 illustrates the closest to the light path element 220 side of the third plane 1003, and in particular, illustrates a cross section at the lower edge of the portion that makes up the third insulating layer 207 of the side surface 204.

The light path element 220 has at least a middle portion 222 and a peripheral portion 221. A peripheral portion 221 is located between the middle portion 222 and the insulating film 200.

The peripheral portion 221 surrounds the middle portion 222. The peripheral portion 221 is made of the same material as the middle portion 222. At least between the portion of the peripheral portion 221 and the portion of the middle portion 222 there is no portion made of material different from the material of the peripheral portion 221 and the middle section 222, and the same material extends from the middle section 222 to the peripheral section 221. Accordingly, it can be said that the peripheral section 221 is inseparable from the middle section 222. It is desirable that between all riferiynym portion 221 and all of the intermediate portion 222 portion was formed of a material different from the material of these portions. With regard to the example shown in FIG. 2, it is desirable that the peripheral portion 221 is in contact with the insulating film 200.

In this embodiment, the refractive index of the middle portion 222 is greater than the refractive index of the insulating film 200. The refractive index of the peripheral portion 221 is greater than the refractive index of the middle portion 222. Accordingly, the refractive index of the peripheral portion 221 is also greater than the refractive index of the insulating film 200.

Thus, the light path element 220 is made of a high refractive index material having a higher refractive index than the refractive index of the insulating film 200. The high refractive index material has a refractive index distribution whose configuration includes a first region of high refractive index and a second region a high refractive index having a higher refractive index than the refractive index of the first region of the high refractive index laziness. In this embodiment, the middle portion 222 represents the first high refractive index region, and the peripheral portion 221 represents the second high refractive index region. FIG. 2A illustrates a situation in which there is a noticeable difference between the refractive indices of the middle portion 222 and the peripheral portion 221. For example, if the refractive index of the middle portion 222 is 1.83 and the refractive index of the peripheral portion 221 is 1.90, when viewed through electron microscope of the observed image of the cross section of the element 220 to create a light path in the direction perpendicular to the main surface 101, you can notice that in the image there is a difference between the average section 222 and peripheral section 221.

To form the distribution of the refractive index when using silicon nitride, you can apply, for example, the following methods. As for the first method, first, a first silicon nitride film is formed on the side surface 204 by increasing the amount of silicon components relative to the nitride components of the film-forming material. After that, a second silicon nitride film is formed on top of the first silicon nitride film by reducing, compared with the formation of the first silicon nitride film, the number of silicon components relative to the number of nitride components of the film-forming material. Moreover, one of the number of silicon components and the number of nitride components, or both, can be different during the formation of the first silicon nitride film and during the formation of the second silicon nitride film. According to this first method, it is possible to form the light path element 220 in which the first silicon nitride film constitutes the peripheral portion 221 and the second silicon nitride film constitutes the middle portion 222. That is why even if the ratio of the components in the stoichiometric composition is Si: N = 3: 4, then regarding the non-stoichiometric composition, in which the ratio of silicon to nitrogen (Si / N) is relatively large, it can be noted that such a composition has a higher refractive index than the refractive index neither chloride of silicon, wherein the silicon to nitrogen ratio (Si / N) is relatively small. As for silicon nitride, obtained by the usual method of film formation, such as the method of chemical vapor deposition (CVD), the ratio of silicon to nitrogen is from 1/2 to 3/2, and usually from 3/5 to 1. Note that the refractive index of silicon nitride, in which the ratio of silicon to nitrogen is 3/4, in other words, the refractive index of silicon nitride for that silicon nitride, the actual composition of which coincides with the stoichiometric composition, can be 2.0.

As for the second method, first, a first silicon nitride film is formed, the adhesive ability and density of the material of which are large, on the side surface 204 by reducing the energy supplied to the film-forming material. After that, on top of the first film of silicon nitride, a second film of silicon nitride is formed, the penetration of which is high and the density of the material is low, by increasing the energy supplied to the film-forming material. Thus, it is possible to form the light path element 220 in which the first silicon nitride film constitutes the peripheral portion 221 and the second silicon nitride film constitutes the middle portion 222. That is why a dense silicon nitride film in which the density of the material is relatively high has a higher index refraction than a coarse-grained film in which the density of silicon nitride is relatively low.

The closer the peripheral portion 221 to the light receiving surface 111, the smaller the thickness of the peripheral portion 221. becomes. Details will be explained with reference to FIG. 2B. The values DS1, DS2, DS3, DS4 and DS5 represent the width (diameter) of the opening portion 201 in cross sections S1 to S5. In this embodiment, the side surface 204 shown in FIG. 1 has a straight taper shape with respect to the light receiving surface 111, and has a ratio of DS1> DS2> DS3> DS4> DS5.

The values DL1, DL2, DL3, DL4 and DL5 represent the width (diameter) of the middle portion 222 in cross sections S1 to S5. The central axis passes through the middle section 222, and this middle section 222 constantly extends along the central axis without gaps. In this embodiment, the middle portion 222 is in the shape of a truncated cone, and the outer surface of the middle portion 222 (the surface on the side of the peripheral portion 221) has a straight taper shape with respect to the light receiving surface 111. The outer surface of the middle portion 222 is concentric with the central axis and has an axial symmetry around the axis of rotation, and also has the relation DL1 <DL2 <DL3 <DL4 <DL5. Note that DL5 is a value smaller than DS5, but extremely close to DS5.

Values TH1, TH2, TH3 and TH4 represent the thickness (width) of the peripheral portion 221 in cross sections S1-S4. In this embodiment, the inner surface of the peripheral portion 221 (the surface on the side of the middle portion 222) and the outer surface of the peripheral portion 221 (the surface on the side of the insulating film 200) are inverse taper shape with respect to the light receiving surface 111. The ratio TH1> TH2> is maintained TH3> TH4> TH5. In this case, the value TH5 (not shown) represents the thickness of the peripheral portion 221 in the cross section S5, represents a value equivalent to the value (DS5-DL5) / 2, and is a value extremely close to 0. Thus, the peripheral portion 221 is constantly extends along the side surface 204 of the insulating film 200 without breaks.

Кроме того, минимальное значение толщины периферийного участка 221 меньше, чем $$\lambda /4\sqrt{(n_1^2-n_0^2)}$$

Толщина периферийного участка 221 имеет максимальное значение на верхнем участке элемента 220 для создания светового тракта (от второй плоскости 1002 до четвертой плоскости 1004). Кроме того, толщина периферийного участка 221 имеет минимальное значение на нижнем участке элемента 220 для создания светового тракта (от четвертой плоскости 1004 до третьей плоскости 1003).In this case, although the ratio (TH1 / TH5) between the maximum value (TH1) and the minimum value (TH5) of the thickness of the peripheral portion 221 is almost infinite, the minimum thickness value of the peripheral portion 221 is equal to or less than half the maximum value (i.e., (maximum value) / (minimum value) ≥ 2. Assuming that the wavelength of the light incident on the light path element 220 is λ, the refractive index of the insulating film 200 is n ₀ and the refractive index of the peripheral portion 221 is n ₁ , the maximum know ix peripheral portion thickness 221 is greater than $$\lambda /2\sqrt{(n_{\mathrm{one}}^2-{\mathrm{<figure-callout\; id="0"\; label="n"\; filenames="00000012.png"\; state="\{\{state\}\}">n</figure-callout>}}_0^2)}$$

In addition, the minimum thickness of the peripheral portion 221 is less than $$\lambda /\mathrm{four}\sqrt{(n_{\mathrm{one}}^2-{\mathrm{<figure-callout\; id="0"\; label="n"\; filenames="00000012.png"\; state="\{\{state\}\}">n</figure-callout>}}_0^2)}$$

The thickness of the peripheral portion 221 has a maximum value in the upper portion of the element 220 to create a light path (from the second plane 1002 to the fourth plane 1004). In addition, the thickness of the peripheral portion 221 has a minimum value in the lower portion of the element 220 to create a light path (from the fourth plane 1004 to the third plane 1003).

Even in the part of the peripheral portion 221, where its thickness is between the minimum value and the maximum value, the thickness in the plane located closer to the light receiving surface 111 is equal to or less than 1/2. In the example shown in FIG. 2A and 2B, the thickness (TH3) of the peripheral portion 221 in the fourth plane 1004 is 1/2 the thickness (TH1) of the peripheral portion 221 in the second plane 1002. In addition, the thickness (TH4) of the peripheral portion 221 in the sixth plane 1006 is less than 1/2 of the thickness (TH2) of the peripheral portion 221 in the fifth plane 1005.

FIG. 3A illustrates field strength distributions at a time when light enters the element 220 to create the light path parallel to the central axis of the element 220 to create the light path, in this embodiment. More specifically, the three field strength distributions are field strength distributions within a plane parallel to the light receiving surface 111, in three positions that differ in height within the light path element 220. The position of the transverse axis indicates the height within the element 220 to create a light path.

Guided by the concepts of wave optics, we can imagine that light tends to concentrate in the region with a high refractive index. Therefore, the field strength of the peripheral portion 221 is greater than the field strength of the middle portion 222, in a position where the thickness of the peripheral portion 221 having a greater refractive index than the refractive index of the middle portion 222 is large. In addition, from the light path element 220 to the insulating film 200 having a lower refractive index than the refractive index of the peripheral portion 221, light leakage is unlikely to occur. Therefore, it is believed that there is suppression of light loss.

In this embodiment, the thickness of the peripheral portion 221 gradually decreases as the peripheral portion 221 approaches the photoelectric conversion portion 110. Therefore, light, the amount of which is at the same level as in the position where the thickness is large, cannot propagate along the peripheral section 221 in that part where the thickness of the peripheral section 221 is small. Accordingly, light whose propagation through the peripheral portion 221 is prevented makes a transition to the middle portion 222. In this embodiment, the same material extends to the peripheral portion 221 and the middle portion 222, and therefore light loss is suppressed at this transition. Generally speaking, it can be understood that the refractive index undergoes an abrupt change at the interface between different materials. On the other hand, the peripheral portion 221 and the middle portion 222 are made of the same material, and therefore, the refractive index at the boundary between the peripheral portion 221 and the middle portion 222 varies monotonously.

When light is emitted from the wider middle portion 222, diffraction between the light path element 220 and the photoelectric conversion portion 110 is prevented, unlike when light is emitted from the narrower peripheral portion 221. Therefore, it is assumed that loss suppression occurs due to the fact that the light emitted from the light path element 220 undergoes diffraction and its passage to the photoelectric conversion section 110 prevents i.

As described above, in this embodiment, it can be assumed that light propagation suppresses light losses between the light path element 220 and the insulating film 200 within the light path element 220, as well as between the light path element 220 and the portion 110 photovoltaic conversion, and accordingly, the sensitivity increases.

As shown in this embodiment, it is desirable that the thickness of the peripheral portion 221 decreases continuously as the peripheral portion 221 approaches the light receiving surface 111. That is, it is desirable that the thickness of the peripheral section 221 decreases monotonically in a narrow sense as the distance to the light receiving surface 111 decreases. In fact, the thickness of the peripheral portion 221 decreases stepwise as the peripheral portion 221 approaches the light receiving surface 111. That is, the thickness of the peripheral portion 221 can be made monotonically decreasing in the broad sense as the distance to the light receiving surface 111 decreases. At the same time, it can be assumed that, with an abruptly decreasing thickness of the peripheral section 221, the aforementioned transition to the middle section 222 is relatively small in that part of the peripheral section 221 where the thickness is constant. Therefore, it can be assumed that when the thickness of the peripheral portion 221 decreases suddenly, the transition to the insulating film 200 is facilitated in addition to the transition to the middle portion 222, and accordingly, losses occur.

FIG. 3B illustrates sensitivity during a change in the angle of incidence relative to the central axis of the element 220 to create a light path in this embodiment. Note that this mode is provided as a comparative example in which the light path element 220 does not have a refractive index distribution. As can be understood from FIG. 3B, in accordance with this embodiment, sensitivity to light incident under inclination is increased. As a result of this, the linearity of the value of F can be improved. Note that when light enters the photoelectric conversion element 1 parallel to its central axis, a focal point is formed on the inner portion of the element 200 to create a light path, and it is also possible to form a focal point between the second plane 1002 and the fourth plane 1004. As a rule, when light enters the photoelectric conversion element 1 parallel to its central axis, a focal point is formed within the middle portion 222. On the other hand, torons, when light enters the photoelectric conversion element 1 at an angle to its central axis, the focal point is essentially formed within the peripheral section 223.

If the insulating film 200 is a multilayer film, the refractive index of part of the layers of this multilayer film may have a value not less than the refractive index of the middle portion 222 of the element 220 to create the light path, and may also have a value not less than the refractive index peripheral portion 221. Such a layer that has a refractive index not less than the refractive index of the first region of a high refractive index will be called an insulating layer with a high refraction index. On the other hand, the remaining layer of the multilayer film having a lower refractive index than the refractive index of the middle portion 222 of the light path element 220, in other words, having a refractive index lower than the refractive index of the first region of the high refractive index, will be referred to as an insulating layer with a low refractive index.

On the one hand, in the case of this embodiment, the third insulating layer 207, the fifth insulating layer 209, the seventh insulating layer 211, the ninth insulating layer 213 and the eleventh insulating layer 215 of the insulating film 200, which are made of silicon oxide or silicate glass and form a side surface 204 sections 201 of the opening are insulating layers with a low refractive index. Insulating layers with a low refractive index surround the element 220 to create a light path. For example, in the case where the refractive index of the middle portion 222 is 1.83 and the refractive index of the peripheral portion 221 is 1.90, when the refractive indices of the third insulating layer 207, the fifth insulating layer 209, the seventh insulating layer 211, the ninth insulating layer 213 and of the eleventh insulating layer 215 are 1.46, these insulating layers are insulating layers with a low refractive index. Note that the second insulating layer 206 is also an insulating layer with a low refractive index, but does not constitute the side surface 204 of the opening portion 201. Although the side surface 204 is shown in FIG. 2B in cross sections S1 to S5, in more detail, the side surface 204 in each of the cross sections is respectively formed by different insulating layers, as can be understood from FIG. 2A. In particular, the side surface 204 in the cross section S1 is formed by the eleventh insulating layer 215, the side surface 204 in the cross section S2 is formed by the ninth insulating layer 213, the side surface 204 in cross section S3 is formed by the seventh insulating layer 211, and the side surface 204 in cross sections S4 and S5 is formed by a third insulating layer 207. On the other hand, since the peripheral portion 221 and the middle portion 222 are made of silicon nitride and, respectively, the insulating film 200, the fourth insulating layer 208, estoy insulating layer 210, the eighth insulating layer 212 and tenth insulating layer 214, which are made of silicon nitride and form the side surface 204 of the opening portion 201, are insulating layers with high refractive index. These high refractive index insulating layers surround element 220 to create a light path. For example, in the case where the refractive index of the middle portion 222 is 1.83 and the refractive index of the peripheral portion 221 is 1.90, when the refractive indices of the fourth insulating layer 208, the sixth insulating layer 210, the eighth insulating layer 212 and the tenth insulating layer 214 are equal 2.03, these insulating layers are insulating layers with a high refractive index. Note that the first insulating layer 205 is also an insulating layer with a high refractive index, but does not constitute the side surface 204 of the opening portion 201. Thus, in this example, the high refractive index insulating layer is made of the same material as the peripheral portion 221 and the middle portion 222, and the low refractive index insulating layer is made of a material different from the materials of the peripheral portion 221 and the middle portion 222.

, толщина изолирующего слоя с низким показателем преломления может не превышать λ/2 $$n_{0H}$$

, а также может не превышать λ/4 $$n_{0H}$$

. Толщина изолирующего слоя с высоким показателем преломления, как правило, равна или больше, чем 0,010 мкм, а также равна или меньше 0,10 мкм.However, it is undesirable for the layer having a refractive index not less than the refractive index of such a light path element 220 (high refractive index layer) to comprise the majority of the side surface 204 of the opening portion 201. The reason is that the propagation of light entering the element 220 to create the light path within the insulating layer with a high refractive index and leakage from the opening portion 201 are likely. Therefore, the side surface 204 of the opening portion 201, which is an insulating layer with a high refractive index, occupies less than half the area of the entire side surface 204 of the opening portion 201, and may occupy less than 1/4 of this area. In other words, in a multilayer film, a layer having a refractive index less than the refractive index of the light path element 220 (insulating layer with a low refractive index) occupies at least half the area of the entire side surface 204 of the opening portion 201, and may occupy at least 3 / 4 of this surface. The area of the side surface 204 that each layer occupies can be adjusted by appropriately setting the thickness of each layer or the angle of the side surface 204. The thickness of one insulating layer with a low refractive index is usually equal to or greater than 0.10 μm, and also equal to or less than 0.60 microns. When it is assumed that the wavelength of the light entering the light path element 220 is λ, and the refractive index of the insulating layer with a low refractive index is $$n_{0H}$$

, the thickness of the insulating layer with a low refractive index may not exceed λ / 2 $$n_{0H}$$

, and may also not exceed λ / 4 $$n_{0H}$$

. The thickness of the insulating layer with a high refractive index is usually equal to or greater than 0.010 μm, and also equal to or less than 0.10 μm.

Second Embodiment

In FIG. 4A is a cross-sectional drawing in a direction perpendicular to the main surface 101 (and the light receiving surface 111) of a part of the photoelectric conversion elements 1 in accordance with the second embodiment, and FIG. 4B is a cross-sectional drawing in a direction parallel to the main surface 101 (and the light receiving surface 111) of a portion of the photoelectric conversion elements 1 in accordance with the second embodiment.

In this embodiment, also the middle portion 222 represents the first high refractive index region, and the peripheral portion 221 represents the second high refractive index region having a higher refractive index, the refractive index of the first high refractive index region (middle portion 222).

The definitions of the first plane 1001, the second plane 1002, the third plane 1003, the fourth plane 1004, the fifth plane 1005, the sixth plane 1006, the values S1-S5, DS1-DS5, DL1-DL5 and TH1-TH5 are the same as those given in connection with FIG. 2A and 2B, and therefore, a description thereof will be omitted.

In this embodiment, also, similarly to that described in connection with the first embodiment, the side surface 204 has a straight taper shape. On the other hand, the middle portion 222 has a cylindrical shape, and the outer surface of the middle portion 222 (the surface on the side of the peripheral portion 221) is perpendicular to the light receiving surface 111. The relation DL1 = DL2 = DL3 = DL4 = DL5 is maintained. In addition, although the inner surface of the peripheral portion 221 (the surface on the side of the middle portion 222) is perpendicular to the light receiving surface 111, the outer surface of the peripheral portion 221 (the surface on the side of the insulating film 200) has a shape with inverse taper with respect to the light receiving surface 111. The ratio TH1 is maintained. > TH2> TH3> TH4> TH5.

A modification (not shown) of this embodiment will now be described. The lateral surface 204 of the insulating film 200 may not be conical, but may be perpendicular to the light receiving surface 111 (DS1 = DS2 = DS3 = DS4 = DS5). In this case, the outer surface of the middle portion 222 should have a shape with a straight taper with respect to the light receiving surface 111 (DLl <DL2 <DL3 <DL4 <DL5). In addition, the side surface 204 of the insulating film 200 may be in the form of a reverse taper, and then the ratio DS1 <DS2 <DS3 <DS4 <DS5 can be maintained. In this case, the outer surface of the middle portion 222 should have a straight taper shape that is less inclined than the side surface 204 with respect to the light receiving surface 111. That is, the ratio DS1-DLl> DS2-DL2> DS3-DL3> DS4 is maintained -DL4> DS5-DL5, as a result of which the relation TH1> TH2> TH3> TH4> TH5 can be realized.

Third Embodiment

In FIG. 5A is a cross-sectional drawing in a direction perpendicular to the main surface 101 (and the light receiving surface 111) of the part of the photoelectric conversion elements 1 in accordance with the third embodiment, and FIG. 5B is a cross-sectional drawing in a direction parallel to the main surface 101 (and the light receiving surface 111) of a part of the photoelectric conversion elements 1 in accordance with the third embodiment.

In this embodiment, also the middle portion 222 represents the first high refractive index region, and the peripheral portion 221 represents the second high refractive index region having a higher refractive index, the refractive index of the first high refractive index region (middle portion 222).

The definitions of the first plane 1001, the second plane 1002, the third plane 1003, the fourth plane 1004, the fifth plane 1005, the sixth plane 1006, the values S1-S5, DS1-DS5, DL1-DL5 and TH1-TH5 are the same as those given in connection with FIG. 2A and 2B, and therefore, a description thereof will be omitted.

In this embodiment, also, similarly to that described in connection with the first embodiment, the side surface 204 has a straight taper shape. On the other hand, part of the upper portion of the middle portion 222 (part from the second plane 1002 to the fifth plane 1005) has a cylindrical shape. The rest of the upper section of the middle section 222 (part from the fifth plane 1005 to the fourth plane 1004) and the lower section of the middle section 222 have the shape of a regular truncated cone. The relation DL1 = DL2 <DL3 <DL4 <DL5 is maintained. In addition, the outer surface of the peripheral portion 221 (the surface on the side of the insulating film 200) has a shape with inverse taper with respect to the light receiving surface 111. The relation TH1> TH2> TH3> TH4> TH5 is maintained.

Fourth Embodiment

In FIG. 6A is a cross-sectional drawing in a direction perpendicular to the main surface 101 (and the light receiving surface 111) of the part of the photoelectric conversion elements 1 in accordance with the fourth embodiment, and FIG. 6B is a cross-sectional drawing in a direction parallel to the main surface 101 (and the light receiving surface 111) of the portion of the photoelectric conversion element 1 in accordance with the fourth embodiment.

In this embodiment, also the middle portion 222 represents the first high refractive index region, and the peripheral portion 221 represents the second high refractive index region having a higher refractive index than the refractive index of the first high refractive index region (middle portion 222).

The definitions of the first plane 1001, the second plane 1002, the third plane 1003, the fourth plane 1004, the fifth plane 1005, the sixth plane 1006, the values S1-S5, DS1-DS5, DL1-DL3 and TH1-TH3 are the same as those given in connection with FIG. 2A and 2B, and therefore, a description thereof will be omitted.

In this embodiment, also, similarly to that described in connection with the first embodiment, the side surface 204 has a straight taper shape and the ratio DS1 DS2> DS3> DS4> DS5 is maintained. On the other hand, this embodiment differs from the first to third embodiments in that the peripheral portion 221 and the middle portion 222 are located between the second plane 1002 and the sixth plane 1006, and not between the sixth plane 1006 and the third plane 1003. In this embodiment , the light path creating element 220 has a radiation portion 2221 having a lower refractive index than the refractive index of the peripheral portion 221. The refractive index of the radiation portion 2221 is larger than the pr breaking of the insulating film 200, and, as a rule, is the same as the refractive index of the middle portion 222. Accordingly, in this embodiment, the middle portion 222 and the emission portion 2221 constitute the first high refractive index region, and the peripheral portion 221 represents the second region a high refractive index having a higher refractive index than the refractive index of the first region of the high refractive index (middle portion 222).

The radiation section 2221 is located between the third plane 1003 and the sixth plane 1006. That is, the radiation section 2221 is located between the middle section 222 and the photoelectric conversion section 110, and more specifically, is located between the bottom surface 203 shown in FIG. 1 and the middle portion 222. The radiation portion 2221 is made of the same material as the middle portion 222 (and the peripheral portion 221) and is inextricable with the middle portion 222. The values DL4 and DL5 shown in FIG. 6B indicate the width (diameter) of the radiation portion 2221. The radiation portion 2221 has the shape of a reverse truncated cone.

In this embodiment, also, similarly to that described in connection with the third embodiment, the portion of the upper portion of the middle portion 222 (the portion from the second plane 1002 to the fifth plane 1005) has a cylindrical shape. In addition, the rest of the upper section of the middle section 222 and part of the lower section of the middle section 222 (part from the fourth plane 1004 to the sixth plane 1006) have the shape of a regular truncated cone.

The rest of the upper section of the middle section 222 (part from the fifth plane 1005 to the fourth plane 1004) and the lower section of the middle section 222 (section from the fourth plane 1004 to the sixth plane 1006) have the shape of a regular truncated cone. The relation DL1 = DL2 <DL3 <DL4 <DL5 is maintained. Note that the radiation section 2221 is in contact with the insulating film 200, and the relations DL4 = DS4 and DL5 = DS5 are maintained. In addition, the ratio TH1> TH2> TH3> TH4 is maintained.

Fifth Embodiment

In FIG. 7A is a cross-sectional drawing in a direction perpendicular to the main surface 101 (and the light receiving surface 111) of the part of the photoelectric conversion elements 1 in accordance with the fifth embodiment, and FIG. 7B is a cross-sectional drawing in a direction parallel to the main surface 101 (and the light receiving surface 111) of a part of the photoelectric conversion elements 1 in accordance with the fifth embodiment.

In this embodiment, also the middle portion 222 represents the first high refractive index region, and the peripheral portion 221 represents the second high refractive index region having a higher refractive index, the refractive index of the first high refractive index region (middle portion 222).

The definitions of the first plane 1001, the second plane 1002, the third plane 1003, the fourth plane 1004, the fifth plane 1005, the sixth plane 1006, the values S1-S5, DS1-DS5, DL3-DL5 and TH3-TH5 are the same as those given in connection with FIG. 2A and 2B, and therefore, a description thereof will be omitted.

In this embodiment, also, similarly to that described in connection with the first embodiment, the side surface 204 has a straight taper shape and the ratio DS1> DS2> DS3> DS4> DS5 is maintained. On the other hand, this embodiment differs from the first to fourth embodiments in that the peripheral portion 221 and the middle portion 222 are located between the fifth plane 1005 and the third plane 1003, and not between the second plane 1002 and the fifth plane 1005.

In this embodiment, the light path creating member 220 has an incidence portion 2212 having a greater refractive index than the refractive index of the middle portion 222. The refractive index of the incidence portion 2212 is greater than the refractive index of the insulating film 200, and is typically the same as the refractive index of the peripheral portion 221. Accordingly, in this embodiment, the middle portion 222 represents the first region of the high refractive index, and the peripheral portion 221 and ca. 2212 fall constitute the second region of high refractive index having a larger refractive index than the refractive index of the first high refractive index region (middle portion 222).

The drop section 2212 is located between the second plane 1002 and the fifth plane 1005. That is, the drop section 2212 is located between the transparent film 319 and the peripheral section 221. The drop section 2212 is made of the same material as the peripheral section 221 (and the middle section 222), and is inextricable with the peripheral portion 221. The values DL1 and DL2 shown in FIG. 7B, the width (diameter) of the drop portion 2212 is displayed. The fall section 2212 has the shape of a reverse truncated cone.

In this embodiment, the middle portion 222 has a cone shape, but may also have a truncated cone shape. The ratio DL3 <DL4 <DL5 is maintained. Note that the drop portion 2212 is in contact with the insulating film 200, and the relations DL4 = DS4 and DL5 = DS5 are maintained. The ratio TH1> TH2> TH3> TH4 is also maintained. A middle portion 222 having such a cone shape or a truncated cone shape can be formed using a method of manufacturing a Spindt device for emitting electrons (i.e., using rotary shadowing).

Sixth Embodiment

In FIG. 8A is a cross-sectional drawing in a direction perpendicular to the main surface 101 (and the light receiving surface 111) of the part of the photoelectric conversion elements 1 in accordance with the sixth embodiment, and FIG. 8B is a cross-sectional drawing in a direction parallel to the main surface 101 (and the light receiving surface 111) of the portion of the photoelectric conversion elements 1 in accordance with the sixth embodiment. In this embodiment, also the middle portion 222 represents the first high refractive index region, and the peripheral portion 221 represents the second high refractive index region having a higher refractive index, the refractive index of the first high refractive index region (middle portion 222).

The definitions of the first plane 1001, the second plane 1002, the third plane 1003, the fourth plane 1004, the fifth plane 1005, the sixth plane 1006, the values S1-S5, DS1-DS5, DL1-DL4 and TH1-TH4 are the same as those given in connection with FIG. 2A and 2B, and therefore, a description thereof will be omitted.

In this embodiment, the light path element 220 has a radiation portion 2211. The radiation portion 2211 is inseparable from the peripheral portion 221 and is made of the same material as the peripheral portion 221. The refractive index of the radiation portion 2211 is greater than the refractive index of the middle portion 222. The thickness of the radiation portion 2211 is small. In this embodiment, the middle portion 222 represents the first high refractive index region, and the peripheral portion 221 and the radiation portion 2211 constitute the second high refractive index region having a higher refractive index than the refractive index of the first high refractive index region (middle portion 222). The value TH5 in FIG. 8B displays the width (diameter) of the radiation portion 2211, and in this case, the equality TH5 = DS5 is maintained.

In the above-described first to sixth embodiments, a mode is described in which the peripheral portion 221 is in contact with the side surface 204 of the insulating film 200. However, one or more layers constituting part of the light path element 220 may lie between the peripheral portion 221 and the side surface 204 of the insulating film 200, while the peripheral portion 221 will not be in contact with the side surface 204 of the insulating film 200.

For example, the light path element 220 may have a low refractive index layer (not shown) having a refractive index lower than the refractive index of the peripheral portion 221 and located between the peripheral portion 221 and the insulating film 200. The refractive index of this low layer the refractive index is greater than the refractive index of the insulating film 200, and may be less than the refractive index of the middle portion 222. Note that the material of the layer with a low refractive index can be the same as the material of the peripheral section 221 (and the middle section 222), or may differ from it. With such a low refractive index layer, light loss can be reduced. In addition, this low refractive index layer may surround the peripheral portion 221.

In addition, for example, the light path element 220 may have a layer with a high refractive index (not shown) between the peripheral portion 221 and the insulating film 200 having a higher refractive index than the refractive index of the peripheral portion 221 and made of a material different from the material peripheral portion 221. However, it can be assumed that with an excessive increase in the refractive index of such a layer with a high refractive index compared to the refractive index of the peripheral the first portion 221 and / or the excessive increase in the thickness of a high refractive index, light entering the member 220 to create a light path, will focus on this layer with a high refractive index. As a result of this, essentially, the advantage in accordance with this embodiment cannot be achieved. Therefore, it is desirable that the difference in refractive index between the peripheral section 221 and the layer with a high refractive index is less than the difference in refractive index between the peripheral section 221 and the middle section 222. It is also desirable that the thickness of the layer with a high refractive index be less in an arbitrary cross section, than the thickness of the peripheral portion 221. Such a layer with a high refractive index or a layer with a low refractive index can perform a function that determines the shape of the periphery ynogo portion 221 or to increase the adhesion portion 201 of the opening member 220 to create a light path. In addition, in the case of using an organic material (resin) as the materials of the peripheral portion 221 and the middle portion 222, the high refractive index layer or the low refractive index layer described above serves as a protective layer (passivation layer) with respect to the organic materials. It is desirable to use silicon nitride as the material of such a protective layer.

Note that on the inner side of the middle portion 222, there may exist a region consisting of a material different from that of which the middle portion 222 is made, or a cavity that is surrounded by a middle portion 222. However, when the refractive index of such a region is less than the index the refraction of the middle portion 222, or when the refractive index of this region is greater than the refractive index of the peripheral portion 221, it is desirable to exclude such a region as much as possible.

A transparent film 319 will now be described, which is a common feature for the first through sixth embodiments. As shown in FIG. 2 and 4-8, a transparent film 319 is applied to the upper surface 202 of the insulating film 200. The transparent film 319 is made of the same material as the peripheral portion 221 and the middle portion 222, and has a greater refractive index than the refractive index of the insulating film 200 ( in this case, the eleventh insulating layer 215). The refractive index of the transparent film 319 is greater than the refractive index of the middle portion 222, and may be the same as the refractive index of the peripheral portion 221. In particular, assuming that the refractive index of the transparent film 319 is n ₃ , the refractive index of the middle portion 222 is n ₂ , and the refractive index of the peripheral portion 221 is n ₁ , it is desirable that the ratio (n ₁ + n ₂ ) / 2 <n ₃ <(3n ₁ -n ₂ ) / 2 is maintained.

A detailed description will now be given of the transparent film 319. As shown in the first embodiment (FIG. 2), the second embodiment (FIG. 4), the third embodiment (FIG. 5), the fourth embodiment (FIG. 6) and the sixth embodiment implementation (Fig. 8), the transparent film 319 has a first region 3191 and a second region 3192. The second region 3192 of the transparent film 319 is made inextricably with the middle section 222, which is the first region of a high refractive index. The first region 3191 of the transparent film 319 is inseparable from the peripheral portion 221, which is the second high refractive index region, and is located on the insulating film 200. The refractive index of the first region 3191 is greater than the refractive index of the second region 3192, and the transparent film 319 has some distribution refractive index. The first region 3191 surrounds the second region 3192. If there is light that has spread in the direction of the upper surface 202 of the insulating film 200 and not the opening portion 201, then the transparent film 319 can direct this light to the light path 220. In particular, before entering the insulating film 200, light tries to propagate within the transparent film 319 (first region 3191) having a higher refractive index than the insulating film 200 having a lower refractive index in order to get into the first region 3191 of the transparent film 319. The light propagating through the transparent film 319 enters the peripheral portion 221 made of the same material as the first region 3191 of the low loss transparent film 319. Therefore, it is possible to increase the light utilization efficiency. To obtain such an advantage, under the assumption that the wavelength of the light incident on the light path element 220 is λ, and the refractive index of the transparent film 319 is n ₃ , the thickness of the transparent film 319 must be within the range of λ / 4 n ₃ or more to 2λ / n ₃ or less. In the fifth embodiment shown in FIG. 7, the transparent film 319 is inextricable with the drop portion 2212, and this transparent film 319 has the same refractive index as the drop portion 2212. The transparent film 319 essentially does not have a refractive index distribution. As described above, in the case where the transparent film 319 has a first region 3191 and a second region 3192, it is desirable that the light can be concentrated in a first region 3191 made inextricably with the peripheral portion 221.

Seventh Embodiment

This embodiment is an embodiment in which the large / small ratio between the peripheral portion 221 and the middle portion 222 that existed in the first embodiment is reversed, and a principle description will be given with reference to FIG. 9A and 9B.

The light path element 220 has at least a middle portion 224 and a peripheral portion 223. The peripheral portion 223 is located between the middle portion 224 and the insulating film 200. The peripheral portion 223 surrounds the middle portion 224. Although the peripheral portion 223 may be made of material different from the material of the middle portion 224, it is desirable that the peripheral portion 223 be made of the same material as the middle portion 224. It is desirable that at least between the portion of the peripheral portion 223 and the portion the middle portion 224 there was no portion made of material different from the materials of the peripheral portion 223 and the middle portion 224, and the same material continued from the middle portion 224 to the peripheral portion 223. In this case, it can be said that the peripheral portion 223 is inextricable with the middle section 224. It is desirable that between the entire peripheral section 223 and the entire middle section 224 there is no section of material different from the materials of both of these sections.

In this embodiment, the refractive index of the peripheral portion 223 is greater than the refractive index of the insulating film 200. Then, the refractive index of the middle portion 224 is greater than the refractive index of the peripheral portion 223. Therefore, the refractive index of the middle portion 224 is also greater than the refractive index of the insulating film 200. In particular, in this embodiment, the peripheral portion 223 represents the first high refractive index region, and the middle portion 224 represents toruyu region of high refractive index having a larger refractive index than the first high refractive index region (peripheral portion 223).

The thickness of the peripheral portion 223 gradually decreases as the peripheral portion 223 approaches the light receiving surface 111. Details of this will be described with reference to FIG. 9B. The values DS1, DS2, DS3, DS4 and DS5 represent the width (diameter) of the opening portion 201 in cross sections S1-S5. In this embodiment, the side surface 204 shown in FIG. 9A has a straight taper shape with respect to the light receiving surface 111, and the dependence DS1> DS2> DS3> DS4> DS5 is maintained.

Values DH1, DH2, DH3, DH4 and DH5 represent the width (diameter) of the middle portion 224 in cross sections S1-S5. In this embodiment, the middle portion 224 has the shape of a truncated cone, and the outer surface of the middle portion 224 (the surface on the side of the peripheral portion 223) has a shape with a straight taper with respect to the light receiving surface 111. The dependence DH1 <DH2 <DH3 <DH4 <DH5 is maintained. . Values TL1, TL2, TL3, TL4 and TL5 represent the thickness (width) of the peripheral portion 223 in cross sections S1-S5. In this embodiment, the inner surface of the peripheral portion 223 (the surface on the side of the middle portion 224) and the outer surface of the peripheral portion 223 (the surface on the side of the insulating film 200) are inversely tapering with respect to the light receiving surface 111. The dependence TL1> TL2> is maintained TL3> TL4> TL5.

Кроме того, минимальное значение толщины периферийного участка 221 меньше, чем $$\lambda /4\sqrt{(n_1^2-n_0^2)}$$

. Толщина периферийного участка 223 имеет максимальное значение на верхнем участке элемента 220 для создания светового тракта (от второй плоскости 1002 до четвертой плоскости 1004). Кроме того, толщина периферийного участка 223 имеет минимальное значение на нижнем участке элемента 220 для создания светового тракта (от четвертой плоскости 1004 до третьей плоскости 1003).In this case, although the ratio (TL1 / TL5) between the maximum value (TL1) and the minimum value (TL5) of the thickness of the peripheral portion 223 is generally infinite, the minimum thickness value of the peripheral portion 223 is at least equal to or less than half the maximum value (i.e. (maximum value / minimum value)> 2). Assuming that the wavelength of the light entering the light path element 220 is λ and the refractive index of the insulating film 200 is n ₀ , and the refractive index of the peripheral portion 223 is n ₁ , the maximum thickness of the peripheral portion 223 is greater than $$\lambda /2\sqrt{(n_{\mathrm{one}}^2-{\mathrm{<figure-callout\; id="0"\; label="n"\; filenames="00000012.png"\; state="\{\{state\}\}">n</figure-callout>}}_0^2)}$$

In addition, the minimum thickness of the peripheral portion 221 is less than $$\lambda /\mathrm{four}\sqrt{(n_{\mathrm{one}}^2-{\mathrm{<figure-callout\; id="0"\; label="n"\; filenames="00000012.png"\; state="\{\{state\}\}">n</figure-callout>}}_0^2)}$$

. The thickness of the peripheral portion 223 has a maximum value in the upper portion of the element 220 to create a light path (from the second plane 1002 to the fourth plane 1004). In addition, the thickness of the peripheral portion 223 has a minimum value in the lower portion of the element 220 to create a light path (from the fourth plane 1004 to the third plane 1003).

Even in the part of the peripheral portion 223, where its thickness is between the minimum value and the maximum value, the thickness in the plane located closer to the light receiving surface 111 is equal to or less than 1/2. In the example shown in FIG. 9A and 9B, the thickness of the peripheral portion 223 in the fourth plane 1004 (TL3) is 1/2 the thickness of the peripheral portion 223 in the second plane 1002 (TL1). In addition, the thickness of the peripheral section 223 in the sixth plane 1006 (TL4) is less than 1/2 the thickness of the peripheral section 223 in the fifth plane 1005 (TL2).

FIG. 10 illustrates field strength distributions at a time when light enters the element 220 to create a light path parallel to the central axis of the element 220 to create a light path, in this embodiment. In more detail, the three field strength distributions are the field strength distributions within a plane parallel to the light receiving surface 111, in three positions that differ in height within the light path element 220. The position of the transverse axis indicates the height within the element 220 to create a light path.

Guided by the concepts of wave optics, we can imagine that light tends to concentrate in the region with a high refractive index. Therefore, the field strength of the middle portion 224 is greater than the field strength of the peripheral portion 223, in a position where the thickness of the middle portion 224 having a greater refractive index than the refractive index of the peripheral portion 223 is large. In addition, most of the light propagates through the middle portion 224, whereby the amount of light that is leaked from the element 220 to create the light path to the insulating film 200 can be reduced. Therefore, it is believed that light loss is suppressed. Accordingly, the efficiency of using the light incident on the photoelectric conversion element 1 parallel to its central axis can be improved in comparison with the first through sixth embodiments. The light parallel to the center axis of the photoelectric conversion element 1 is essentially light introduced perpendicular to the light receiving surface of the photoelectric conversion section 110 and is light that typically incident on the photoelectric conversion section 110. Accordingly, it is possible to obtain photoelectric converting elements 1 having high sensitivity.

The author of the present invention and other persons have conducted a sensitivity study when light enters the element 220 to create a light path parallel to the central axis of the element 220 to create a light path in accordance with three models constructed under the assumption that the wavelength of incident light is 550 nm (green light ), the refractive index of the insulating film 200 is 1.46, and the refractive index of the element 220 to create the light path is from 1.83 to 1.90. The first model is a model in which the refractive index of the middle portion and the refractive index of the peripheral portion are both 1.83, and the light path element 220 does not have a refractive index distribution. The second model is a model in which the refractive index of the middle portion and the refractive index of the peripheral portion are both 1.90, and the light path element 220 does not have a refractive index distribution. The third model is a model corresponding to this embodiment in which the refractive index of the middle portion 224 is 1.90 and the refractive index of the peripheral portion 223 is 1.83. If the normalized sensitivity according to the first model was 1.00, then the normalized sensitivity of the third model would be 1.05, and the normalized sensitivity of the second model would be 1.04. Thus, the third model can increase the sensitivity of the photoelectric converting elements 1 by setting the refractive index of the middle portion 224 higher than the refractive index of the peripheral portion 223 relating to the first model, or by setting the index of the peripheral portion 223 lower than the refractive index of the middle portion 224 relating to the second model.

Note that a layout that modifies the seventh embodiment can be applied in which the large / small ratio between the peripheral portion 221 and the middle portion 222 that existed in the first to sixth embodiments is reversed. For example, an arrangement is possible in which the peripheral portion 221 is taken as the first high refractive index region, and the middle portion 222 and the radiation portion 2221 are taken as the second high refractive index region having a higher refractive index than the first high refractive index region (peripheral portion 221) , in accordance with the fourth embodiment. Alternatively, an arrangement is possible in which the peripheral portion 221 and the incidence portion 2212 are taken as the first high refractive index region and the middle portion 222 is taken as the second high refractive index region having a higher refractive index than the first high refractive index region (peripheral portion 221), in accordance with the fifth embodiment. In addition, an arrangement is possible in which the peripheral portion 222 and the radiation portion 2211 are taken as the first high refractive index region and the middle portion 222 is taken as the second high refractive index region having a higher refractive index than the first high refractive index region (peripheral portion 221 ), in accordance with the sixth embodiment.

In addition, the transparent film 319 has a first region 3193 and a second region 3194. The second region 3194 of the transparent film 319 is made inextricably with the middle portion 224, which is the first region of a high refractive index. The first region 3193 of the transparent film 319 is made inextricably with the peripheral portion 223, which is the second high refractive index region, and is located on the insulating film 200. The refractive index of the second region 3194 is greater than the refractive index of the first region 3193, and the transparent film 319 has some distribution refractive index. The first region 3193 surrounds the second region 3194. Thus, the light incident on the transparent film 319 can be directed to the middle portion 224 of the element 220 to create the light path, and the light utilization efficiency can be improved.

The seventh embodiment provides a mode in which the peripheral portion 221 is in contact with the side surface 204 of the insulating film 200. However, similarly to the first to sixth embodiments, one or more layers constituting part of the light path creating element may lie between the peripheral portion 223 and the side surface 204 of the insulating film 200, and the peripheral portion 223 will not be in contact with the side surface 204 of the insulating film 200.

For example, in one embodiment, the light guide path may have a low refractive index layer (not shown) having a lower refractive index than the refractive index of the peripheral portion 223, between the peripheral portion 221 and the insulating film 200. The refractive index of this low refractive index layer greater than the refractive index of the insulating film 200, and may be less than the refractive index of the middle portion 224. Note that the material of the layer with a low refractive index is e thus that the peripheral portion of the material 223 (and the middle portion 224) or may differ from it. With such a low refractive index layer, light loss can be reduced. In addition, this low refractive index layer may surround the peripheral portion 223.

In addition, for example, the configuration of the light guide channel may have a layer with a high refractive index (not shown) having a higher refractive index than the refractive index of the peripheral section 223, and made of a material different from the material of the peripheral section 223. However, we can assume that with an excessive increase in the refractive index of such a layer with a high refractive index compared with the refractive index of the peripheral section 223 and / or with an excessive increase in thickness c With a high refractive index, light entering the light path element 220 will concentrate on this high refractive index layer. As a result of this, essentially, the advantage in accordance with this embodiment cannot be achieved. Therefore, it is desirable that the difference in the refractive index between the peripheral section 223 and the high refractive index layer is less than the difference in the refractive index between the peripheral section 223 and the middle section 224. It is also desirable that the thickness of the layer with the high refractive index be smaller in an arbitrary cross section, than the thickness of the peripheral portion 221. Such a layer with a high refractive index or a layer with a low refractive index can perform a function that determines the shape of the periphery ynogo portion 221 or to increase the adhesion portion 201 of the opening member 220 to create a light path. In addition, in the case of using an organic material (resin) as the materials of the peripheral portion 221 and the middle portion 222, the high refractive index layer or the low refractive index layer described above serves as a protective layer (passivation layer) with respect to the organic materials. It is desirable to use silicon nitride as the material of such a protective layer.

To form the distribution of the refractive index when using silicon nitride, you can apply, for example, the following methods. As for the first method, first, a first silicon nitride film is formed on the side surface 204 by reducing the amount of silicon components relative to the nitride components of the film-forming material. After that, a second silicon nitride film is formed on top of the first silicon nitride film by increasing — compared with the formation of the first silicon nitride film — the amount of silicon components relative to the nitride components of the film-forming material. Moreover, one of the number of silicon components and the number of nitride components, or both, can be different during the formation of the first silicon nitride film and during the formation of the second silicon nitride film. According to this first method, it is possible to form a light path element 220 in which the first silicon nitride film constitutes the peripheral portion 223 and the second silicon nitride film constitutes the middle portion 224. That is why even if the ratio of the components in the stoichiometric composition is Si: N = 3: 4, then regarding the non-stoichiometric composition in which the ratio of silicon to nitrogen (Si / N) is relatively large, it can be noted that such a composition has a higher refractive index than the refractive index of nitride to belt, in which the ratio of silicon to nitrogen (Si / N) is relatively small

As for the second method, first, a first silicon nitride film is formed, the material density of which is low, on top of the side surface 204 by a relative increase in the energy supplied to the film-forming material. After that, a second silicon nitride film is formed, the material density of which is higher than that of the first silicon nitride film, by reducing the energy supplied to the film-forming material compared to the formation of the first silicon nitride film. Thus, it is possible to form the light path element 220 in which the first silicon nitride film constitutes the peripheral portion 223 and the second silicon nitride film constitutes the middle portion 224. That is why a dense silicon nitride film in which the density of the material is relatively high has a higher index refraction than a coarse-grained nitride film in which the density of silicon nitride is relatively low.

Details of Photovoltaic Converting Elements

A detailed description of an example of photovoltaic conversion elements 1 will be given with reference to FIG. 1. An N ⁺ type semiconductor region 112 is embedded in a semiconductor substrate 100 made of N-type silicon. For a circle including a lower portion of an N ⁺ type semiconductor region 112, an N-type conductor region 113 is provided. For the lower portion, an N-type conductor region 113 is provided with a P-type semiconductor region 114. An N ⁺ -type semiconductor region 112 serves as a charge storage region. The N ⁺ type semiconductor region 112, the N-type conductor region 113, and the P-type semiconductor region 114 form part of the photoelectric conversion section 110.

The surface of the input side (the upper surface in Fig. 1) of the first layer 328 of the lens substrate has a convex ideal spherical surface or an aspherical surface towards the input side (collectively referred to as a "curved surface" in the following text), i.e. has the shape of a convex lens. Thus, the light entering the lens body layer 329 approaches the central axis and condenses. The lens substrate layer 328 and the lens body layer 329 are mutually made of the same organic material (resin), the lens substrate layer 328 and the lens body layer 329 being in contact with each other. That is, the lens substrate layer 328 and the lens body layer 329 are substantially integrally formed. It is often difficult to observe the boundary between the lens substrate layer 328 and the lens body layer 329. In this case, the plane connecting the edges of the curved surface region with the layer 329 of the lens body can be set as an imaginary boundary. Note that an arrangement is possible in which the first layer 329 of the lens body and the layer 327 of the color filter are in contact with each other due to the absence of the first layer 328 of the lens substrate.

The material properties (in particular, the refractive index) and the shape of the curved surface (in particular, its curvature, height and width) of the first layer 329 of the lens body have a huge impact on the position of the focal point. Generally speaking, the greater the curvature given, the farther the position of the focal point from the first plane 1001. The material properties (in particular, the refractive index) and the thickness of the lens substrate layer 328 affect the distance that light is closer to the central axis within layer 328 lens substrates, and these features, respectively, constitute one of the factors for determining the focal point. A typical refractive index of the first layer 329 of the lens body is from 1.6 to 2.0.

The color filter layer 327 is made of an organic material (resin), including a coloring material. Although paint may be used as a coloring material, pigment may also be used. The material properties (in particular, the refractive index) and the thickness of the color filter layer 327 affect the distance that light reflected on the interface between the lens substrate layer 328 and the color filter layer 327 becomes closer to the central axis within the color filter layer 327 , and these features, respectively, constitute one of the factors for determining the focal point 500. A typical layer thickness 327 of a color filter is from 0.1 to 1.0 μm, and a typical refractive index is from 1.4 d about 1.6.

The flattened film 326 consists of organic material (resin) and has the function of adjusting the distance between the first layer 329 of the lens body and the second layer 324 of the lens body. In addition, the flattened film 326 is flattened to such an extent that it takes the form of a curved surface of the second layer 324 of the lens body, and has the function of suppressing the inclination of the light path in the layer 327 of the color filter, the first layer 328 of the lens substrate and the first layer 329 of the lens body. The thickness of the thinnest portion of the flattened film 326, as a rule, is from 0.1 to 0.5 μm, and the refractive index of the flattened film is from 1.4 to 1.5.

The second lens holder layer 323 and the second lens body layer 324 are made of silicon nitride, and the second lens body layer 324 has the shape of a convex lens (flat-convex lens shape). Note that the refractive index of the second layer 324 of the lens body is greater than the refractive index of the flattened film 326. Therefore, additional condensation of light condensing in the first layer 329 of the lens body is possible.

The second lens body coating layer 325 is made of silicon oxide and has a refractive index between the refractive index of the second lens body layer 324 and the refractive index of the flattened film 326. Thus, if the second lens body coating layer 325 has a refractive index between the refractive index of the second layer 324 of the lens body and the refractive index of the flattened film 326, the amount of light incident from the flattened film 326 on the second layer 324 of the lens body increases. That is why it is possible to suppress reflection at the interface between the tapered film 326 and the second layer 324 of the lens body, which can occur if a second layer 325 of the coating of the lens body is not provided, and the transmittance can be increased.

In one embodiment, the thickness of the second lens body coating layer 325 is less than the thickness of the second lens body layer 324, and the thickness of the second lens body layer 324 is equal to or less than 1/2. The thickness of the second coating layer 325 of the lens body is (M-0.5) / 4n ₃₂₅ - (M + 0.5) / 4n ₃₂₅ times greater than the wavelength of the incident light, and this thickness can also be M / 4n ₃₂₅ times longer than the wavelength of the incident light. Here, M is an odd number, and n ₃₂₅ is the refractive index of the second coating layer 325 of the lens body. M is 1 or 3. If the thickness of the second coating layer 325 of the lens body is set in this way, interference due to reflected light on the surface of the second lens body layer 324 can be reduced, and the amount of reflected light on the surface of the second body coating layer 325 can be reduced. lenses, and therefore the function of suppressing reflection - from the point of view of fiber optics - is performed.

The first middle refractive index layer 322 is provided between the second lens substrate layer 323 and the low refractive index layer 321, and the second middle refractive index layer 320 is provided between the low refractive index layer 321 and the transparent film 319. The materials of the first average refractive index layer 322 the refractive index and the second average refractive index layer 320 are composed of silicon oxynitride, and the material layer 321 with a low refractive index is silicon oxide.

The upper surface of the first average refractive index layer 322 forms an interface along with the lower surface of the second lens substrate layer 323, and the refractive index of the first average refractive index layer 322 is less than the refractive index of the second lens substrate layer 323. The upper surface of the low refractive index layer 321 forms an interface with the lower surface of the first average refractive index layer 322, and the refractive index of the low refractive index layer 321 is less than the refractive index of the first average refractive index layer 322. Therefore, the first average refractive index layer 322 has a refractive index between the refractive index of the second lens substrate layer 323 and the refractive index of the low refractive index layer 321. The upper surface of the second middle refractive index layer 320 forms an interface along with the lower surface of the low refractive index layer 321, and the refractive index of the second average refractive index layer 320 is greater than the refractive index of the low refractive index layer 321. The lower surface of the second average refractive index layer 320 forms an interface along with the upper surface of the transparent film 319, and the refractive index of the second average refractive index layer 320 is less than the refractive index of the transparent film 319. Therefore, the second average refractive index layer 320 has an index the refractive index between the refractive index of the low refractive index layer 321 and the refractive index of the transparent film 319. Thus, the refractive index is any o of the first layer 322 with an average refractive index and the second layer 320 with an average refractive index less than the refractive indices of the second layer 323 of the lens substrate and the second layer 324 of the lens body, and therefore the first layer 322 with an average refractive index, layer 321 with a low refractive index and the second medium refractive index layer 320 can be collectively referred to as a low refractive index film. Note that at least one of the first average refractive index layer 322 and the second average refractive index layer 320 can be excluded from the low refractive index film, and the low refractive index film can be mistaken for a single-layer film or a two-layer film. Note that a film with a low refractive index can also be excluded.

The refractive index of the film 321 with a low refractive index is less than the refractive index of the first layer 322 with an average refractive index, and therefore the light is reflected in accordance with the Shell law towards the central axis of the opening portion 201 and to the light path 220 to create the light path within the layer 321 low refractive index. Therefore, the amount of light entering the opening portion 201 (into the light path element 220) can be increased. Even if there is no first refractive index layer 322, the refractive index of the low refractive index film 321 is less than the refractive index of the first average refractive index layer 322, and therefore, the same refraction can occur. However, in accordance with the difference in the refractive index between the second layer 323 of the lens substrate and the low refractive index layer 321, reflection of incident light may occur on the interface between the second layer 323 of the lens substrate and the low refractive index layer 321. In addition, in accordance with the difference in refractive index between the low refractive index layer 321 and the transparent film 319, reflection of incident light may occur on the interface between the low refractive index layer 321 and the transparent film 319. The reflectance R can be represented by the expression R = (n ₃₂₁ -n ₃₁₉ ) ² / (n ₃₂₁ + n ₃₁₉ ) ² . In this case, n ₃₂₁ is the refractive index of the low refractive index layer 321, and n ₃₁₉ is the refractive index of the transparent film 319. In the example of FIG. 1, both the difference in the refractive index between the second layer 323 of the lens substrate and the first layer 322 with an average refractive index, and the difference in the refractive index between the first layer 322 with an average refractive index and the layer 321 with a low refractive index is smaller than the difference in the refractive index between the second layer 323 the lens substrate and a low refractive index layer 321. Accordingly, transmission from the second lens substrate layer 323 to the low refractive index layer 321 can be improved, and the amount of light entering the low refractive index layer 321 can be increased. The refractive index of the transparent film 319 is greater than the refractive index of the second layer 320 with an average refractive index, and therefore, the light is refracted according to the Shell law in the direction from the central axes of the opening portion 201 and the light path inside the transparent film 319. Therefore, the light flux falling onto the peripheral portion 221 (or peripheral portion 223) can be increased. In addition, since the angle with respect to the side surface 204 can be reduced, the flux of light incident on the side surface 204 at an angle of incidence not less than the critical angle can be increased, and the amount of light leaking from the side surface 204 of the opening portion 201 can be reduced. Even if the second layer 320 with the average refractive index is excluded, such refraction can occur because the refractive index of the low refractive index layer 321 may become lower than the refractive index of the transparent film 319. In the example of FIG. 1, as the difference in the refractive index between the low refractive index layer 321 and the second average refractive index layer 320, the difference in the refractive index between the second medium refractive index layer 320 and the transparent film 319 is smaller than the difference in refractive index between the 321 sec layer low refractive index and transparent film 319. Accordingly, transmission from the low refractive index layer 321 to the transparent film 319 can be improved, and the amount of light incident on the transparent film 319 You can increase.

In one embodiment, the thickness of the first layer 322 with an average refractive index is (M-0.5) / 4n ₃₂₂ - (M + 0.5) 4n ₃₂₂ times the wavelength of the incident light, and this thickness can also be in M / 4n ₃₂₂ times the wavelength of the incident light. Here, M is an odd number, and n ₃₂₂ is the refractive index of the first layer 322 with an average refractive index. M is 1 or 3. If the thickness of the first layer 322 with an average refractive index is set in this way, it is possible to reduce the interference of reflected light on the interface between the first layer 322 with an average refractive index and the second layer 323 of the lens substrate, and it is also possible to reduce the number reflected light at the interface between the first layer 322 with an average refractive index and the layer 321 with a low refractive index; accordingly, it is possible to fulfill the function of suppressing reflection from the point of view of wave optics.

Similarly, the thickness of the second layer 320 with an average refractive index of (M-0.5) / 4n ₃₂₀ is (M + 0.5) / 4n ₃₂₀ times the wavelength of the incident light, and the thickness of this layer can be in M / 4n ₃₂₀ times the wavelength of the incident light. Here M is an odd number, and n ₃₂₀ is the refractive index. M is 1 or 3.

In order to increase the refraction in order to pass the light closer to the central axis within the film with a low refractive index in the range where the thickness of each layer is limited, it is desirable to set the thickness of the first layer 322 with an average refractive index and the thickness of the layer 321 with a low refractive index as follows. Firstly, the relative refractive index between the second layer 323 of the lens substrate and the first layer 322 with an average refractive index is compared and the relative refractive index between the first layer 322 with an average refractive index and the low refractive index layer 321. The thickness of the medium (one of the first layer 322 with an average refractive index and the layer 321 with a low refractive index) on the output side, where the relative refractive index is greater, is set as exceeding the thickness of the medium (the other of the first layer 322 with an average refractive index and the layer 321 with a low refractive index) on the input side, where the relative refractive index is less. Note that the relative refractive index referred to here is the ratio (refractive index of the medium on the input side) / (refractive index of the medium on the output side), and its value is greater than 1 in this embodiment. Note that when in the previous description it was simply a question of a "refractive index", this meant that we mean the absolute refractive index. According to Shell's law, the larger the relative refractive index, the larger the exit angle, as a result of which the emitted light can be further approximated to the central soybean by increasing the thickness of the medium on the output side, where the relative refractive index is greater. For example, if the refractive index of the second layer 323 of the lens substrate is 2.00, the refractive index of the first layer 322 with an average refractive index is 1.72, and the refractive index of the low refractive index layer 321 is 1.46, then the relation 2 00 / 1.72 <1.72 / 1.46. Accordingly, the thickness of the low refractive index layer 321 should be increased in comparison with the thickness of the first average refractive index layer 322.

Photoelectric conversion device

and image reading system

Now, with reference to FIG. 11, an example of a photoelectric conversion device 10 and an image reading system 30 will be described. The photoelectric conversion device 10 can be used, for example, as an image sensor, a distance sensor or a photometric sensor. The photoelectric conversion device 10 may also have numerous functions from among the functions of an image sensor, a distance sensor or a photometric sensor.

The image pickup system 30 includes a photoelectric conversion device 10, and a signal processing device 20 may also be integrated into it, into which an electrical signal output from the photoelectric conversion device 10 is input to process this electrical signal. In FIG. 11 is a drawing illustrating an example of an image reading system 30. From the outputs OUT1 and OUT2 of the photoelectric conversion device 10, electrical signals are generated. Although an example is provided in which there are two dispensing routes according to the outputs EX1 and EX2, the number of dispensing routes may be one, or may be three or more. Electrical signals are input to the input VX of the device 20 for processing signals. The electrical signals may be current signals or voltage signals, and may also be analog signals or digital signals. Instead of electrical signals, light signals can be used.

In the case of using the photoelectric conversion device 10 as an image sensor, the signal processing device 20 is configured to provide image signals from output OUT3 by inputting electrical signals to input IN. In the case of using the photoelectric conversion device 10 as a distance sensor for detecting a focal point, the signal processing device 20 is configured to provide a drive signal to output the OUT 3 to drive the lens provided in front of the photoelectric conversion device 10 by inputting electrical signals to the input VX. In the case of using the photoelectric conversion device 10 as a photometric sensor, the signal processing device 20 is configured to provide a control signal for controlling the shutter to adjust the exposure time from output OUT3 by inputting electrical signals to input IN. Note that the aforementioned shutter may be a mechanical shutter or an electronic shutter, and in the case of an electronic shutter, the photoelectric conversion device 10 is substantially controllable. In particular, it is convenient to use the photoelectric conversion device 10 in accordance with this invention as an image sensor, obtaining satisfactory images with it.

An example of a photovoltaic conversion device 10 in the image reading system 30 shown in FIG. 11. In this example, a photoelectric conversion device is used as the image sensor, which provides amplification of pixel signals and serves as a photoelectric conversion device 10. In FIG. 11, the photoelectric conversion device 10 includes a pixel region 611, a vertical scan circuit 612, two readout circuits 613, two horizontal scan circuits 614 and two output amplifiers 615. The non-pixel region will be referred to as the peripheral region.

In the region of 611 pixels, a large number of photoelectric conversion elements 1 are arranged in the form of a two-dimensional formation. Each of the photoelectric conversion elements 1 is equivalent to one pixel. The interval between the central axes of mutually adjacent photoelectric converting elements 1 (pixel pitch) is usually equal to or less than 10 μm, equal to or less than 5.0 μm, and may not exceed 2.0 μm. In the field of peripheral circuits, read circuits 613 and, for example, a column amplifier, a color display system (SCO) scheme, etc., are provided that subject a signal read by the vertical signal bus from a pixel in a row selected by the vertical scan circuit 612 addition or similar operation. For each column, or for every few columns, a column amplifier, a SSC scheme, a summing scheme, etc. are provided. The horizontal scanning circuits generate signals for sequentially reading the signals of the reading circuits 613. The output amplifiers amplify and provide signals in the columns selected by the horizontal scanning circuits 614.

The above configuration is only an example of the configuration of the photovoltaic conversion device 10, and the present invention is not limited thereto. Reading circuits 613, horizontal scanning circuits 614 and output amplifiers 615 form the delivery routes (from outputs EX1 and EX22) of the two systems, and therefore they are located at some point in time so that one is above the region of 611 pixels, the other is below it, and it turns out to be concluded between them.

Examples of a typical image reading system 30 include filming apparatuses, such as cameras for taking acting samples, working moments and promotional photographs, video cameras, etc. The image reading system 30 may also include a transport unit (not shown) that provides transportation of the photovoltaic conversion device 10. Examples of the transport unit include wheels with an electric motor, a piston engine, a rotary piston engine, or the like as a power source, and also include propulsion devices such as propellers, turbo engines, rocket engines, etc. Such an image reading system including a transport unit can be implemented by installing a photovoltaic conversion device 10 and a signal processing device 20 on a car, railway carriage, ship, plane, satellite or similar object.

As described above, using the present invention, which has first through seventh embodiments, it is possible to obtain photovoltaic conversion elements having high light utilization efficiency. In particular, in the first to sixth embodiments included in the first aspect of the present invention, it is possible to provide photovoltaic cells with increased linearity of F. In addition, in the seventh embodiment included in the second aspect of the present invention, it is possible to provide photovoltaic cells with hypersensitivity to light parallel to the central axis.

Although the present invention has been described with reference to possible embodiments, it should be clear that the invention is not limited to the described possible embodiments. The scope of the claims of the following claims should be construed in the broadest sense as encompassing all such modifications and equivalent structures.

Claims (28)

1. Photovoltaic conversion element containing
plot of photovoltaic conversion and
an element for creating a light path to said photoelectric conversion section deposited on said photoelectric conversion section and surrounded by an insulating film,
wherein said element includes
first section and
a second portion having the same stoichiometric composition as said first portion, and also having a higher refractive index than the refractive index of said first portion,
and wherein said second section is made inextricably with said first section and surrounds said first section, and the refractive index of said first section is greater than the refractive index of said insulating film, within a plane parallel to the light receiving surface of said photoelectric conversion section, and within another a plane parallel to said light receiving surface and being closer to said light receiving surface than said some th plane
and wherein the thickness of said second portion within said other plane is less than the thickness of said second portion within said certain plane. 2. A photovoltaic conversion element containing
plot of photovoltaic conversion and
an element for creating a light path to said photoelectric conversion section deposited on said photoelectric conversion section and surrounded by an insulating film, said insulating film including a first insulating layer and a second insulating layer of silicon oxide or silicate glass,
wherein said element includes
the first portion of silicon nitride and
a second portion of silicon nitride having a higher density of silicon nitride than the density of silicon nitride in said first portion,
and wherein said second section is located between said first section and said first insulating layer, and said second section is made inextricably with said first section and surrounds said first section within a plane parallel to the light receiving surface of said photoelectric conversion section,
and wherein said second section is located between said first section and said second insulating layer, and, in addition, said second section is made inextricably with said first insulating section and surrounds said first section within another plane parallel to the light receiving surface of said photoelectric conversion section and located closer to said light receiving surface than said certain plane,
and wherein the thickness of said second section within said other plane is less than the thickness of said second section within said certain plane. 3. Photovoltaic conversion element containing
plot of photovoltaic conversion and
an element for creating a light path to said photoelectric conversion section deposited on said photoelectric conversion section and surrounded by an insulating film, said insulating film including a first insulating layer and a second insulating layer of silicon oxide or silicate glass,
wherein said element includes
the first portion of silicon nitride and
a second silicon nitride section having a larger silicon index for nitride than the silicon index for nitride of said first section,
and wherein said second section is located between said first section and said first insulating layer and said second section is made inextricably with said first section and surrounds said first section within a plane parallel to the light receiving surface of said photoelectric conversion section,
and wherein said second portion is located between said first portion and said second insulating layer and said second portion is inseparable from said first portion and surrounds said first portion within another plane parallel to said light receiving surface of the photoelectric conversion section and being closer to said light receiving surface than the mentioned some plane,
and wherein the thickness of said second section within said other plane is less than the thickness of said second section within said certain plane. 4. A photovoltaic conversion element containing
plot of photovoltaic conversion and
an element for creating a light path to said photoelectric conversion section deposited on said photoelectric conversion section and surrounded by an insulating film,
wherein said element includes
first section and
a second portion having a lower refractive index than the refractive index of said first portion,
and wherein said second section is made inextricably with said first section and surrounds said first section, and the refractive index of said second section is greater than the refractive index of said insulating film, within a plane parallel to the light receiving surface of said photoelectric conversion section, and within another a plane parallel to said light receiving surface and being closer to said light receiving surface than said some th plane
and wherein the thickness of said second portion within said other plane is less than the thickness of said second portion within said certain plane. 5. Photovoltaic conversion element containing
plot of photovoltaic conversion and
an element for creating a light path to said photoelectric conversion section deposited on said photoelectric conversion section and surrounded by an insulating film, said insulating film including a first insulating layer and a second insulating layer of silicon oxide or silicate glass,
wherein said element includes
the first portion of silicon nitride and
a second portion of silicon nitride having a lower density of said silicon nitride than the density of said first portion,
and wherein said second section is located between said first section and said first insulating layer and said second section is made inextricably with said first section and surrounds said first section within a plane parallel to the light receiving surface of said photoelectric conversion section,
and wherein said second section is located between said first section and said second insulating layer, and said second section is inseparable from said first section and surrounds said first section within another plane parallel to said light receiving surface and being closer to said light receiving surface than said some plane
and wherein the thickness of said second section within said other plane is less than the thickness of said second section within said certain plane. 6. Photovoltaic conversion element containing
plot of photovoltaic conversion and
an element for creating a light path to said photoelectric conversion section deposited on said photoelectric conversion section and surrounded by an insulating film, said insulating film including a first insulating layer and a second insulating layer of silicon oxide or silicate glass,
wherein said element includes
the first portion of silicon nitride and
a second silicon nitride section having a silicon index for nitride lower than a silicon index for nitride of said first section,
and wherein said second section is located between said first section and said first insulating layer and said second section is made inextricably with said first section and surrounds said first section within a plane parallel to the light receiving surface of said photoelectric conversion section,
and wherein said second section is located between said first section and said second insulating layer and said second section is inseparable from said first section and surrounds said first section within another plane parallel to the light receiving surface of said photoelectric conversion section and being closer to said light receiving surface than the mentioned some plane,
and wherein the thickness of said second section within said other plane is less than the thickness of said second section within said certain plane. 7. The photovoltaic conversion element according to claim 4, in which said second section has the same stoichiometric composition as said first section. 8. The photovoltaic conversion element according to any one of claims 1 to 6, in which the refractive indices of said first portion and said second portion continuously vary from an axis perpendicular to said light receiving surface and passing through said first portion towards said insulating film within said some plane and said other plane. 9. The photovoltaic conversion element according to any one of claims 1 to 6, in which the thickness of said second section within said other plane is equal to or less than half the thickness of said second section within said certain plane. 10. The photovoltaic conversion element according to claim 9, in which said element is provided within a portion of the opening of said insulating film, which has a side surface that is inextricably extending from the upper surface of said insulating film and a lower surface that is inextricable with said side surface, and wherein a plane including said light receiving surface is taken as a first plane, and a plane including said upper surface parallel to said first plane, n inyata for the second plane, wherein the plane of said bottom is positioned between said first plane and said second plane within a third plane parallel to said first plane,
and wherein the plane located at the same distance from said second plane and said third plane parallel to said third plane is taken as the fourth plane,
and wherein the plane located at the same distance from said second plane and said fourth plane parallel to said first plane is taken as the fifth plane,
and wherein the plane located at the same distance from said third plane and said fourth plane parallel to said first plane is taken as the sixth plane,
and wherein said certain plane is said fifth plane or is located between said fourth plane and said fifth plane, and said other plane is located between said third plane and said fourth plane. 11. The photovoltaic converting element according to any one of claims 1 to 6, in which, if we take the length of the light entering the said element equal to λ, the refractive index of said insulating film is n ₀ and the refractive index of said second section is n ₁ , then the maximum the thickness value of said second portion is greater than $$\lambda /2\sqrt{(n_{\mathrm{one}}^2-n_0^2)}$$

and the minimum thickness value of said second portion is less than $$\lambda /\mathrm{four}\sqrt{(n_{\mathrm{one}}^2-n_0^2)}$$

. 12. The photovoltaic conversion element according to claim 1 or 4, wherein said insulating film is a multilayer film including
the first and second insulating layers with a high refractive index, each of which has a refractive index not less than the refractive indices of at least one of said first section and said second section, and surround said element, and
the first and second insulating layers with a low refractive index, each of which has a refractive index less than the refractive indices of both of said first section and said second section, and surround said element,
and wherein the thickness of each of said first and second insulating layers with a high refractive index is less than the thickness of each of said first and second insulating layers with a low refractive index,
and wherein said first low refractive index insulating layer is disposed between said first low refractive index insulating layer and said second low refractive index insulating layer,
and said first insulating layer with a low refractive index is located within said certain plane, and said second insulating layer with a low refractive index is located within said other plane, and wherein the thickness of said second portion within said other plane is equal to or less than half the thickness said second portion within said plane. 13. The photovoltaic conversion element according to any one of claims 2, 3, 5, and 6, wherein said insulating film includes third and fourth insulating layers of silicon nitride, each of which surrounds said element and each has a thickness equal to or greater than 0.01 μm, as well as equal to or less than 0.10 μm, the first insulating layer being located between said third insulating layer and said fourth insulating layer, and the thickness of said second portion within said other plane is equal to or less than half the thickness of said second portion within said plane. 14. The photovoltaic conversion element according to any one of claims 1 to 3, in which said element includes a third region having the same stoichiometric composition as said second region and having a refractive index higher than the refractive index of said first region, between said first section and said section of photoelectric conversion, or a photoelectric conversion element according to any one of claims 4 to 6, in which said element for creating a light path to said section of photoelectric eskogo conversion includes a third portion having the same stoichiometric composition as that of said second portion, and also having a smaller refractive index less than the refractive index of said first portion between said first portion and said photoelectric conversion portion. 15. The photovoltaic conversion element according to any one of claims 1 to 6, wherein said second portion is in contact with said insulating film, or a layer with a low refractive index having a lower refractive index than the index is provided between said second portion and said insulating film refraction of said second portion. 16. The photovoltaic conversion element according to any one of claims 1 to 6, containing
a high refractive index layer having a stoichiometric composition different from said second portion and having a greater refractive index than the refractive index of said second portion between said second portion and said insulating film. 17. The photovoltaic conversion element according to any one of claims 1 to 6, in which the width of said element within said other plane is less than the width of said element within said certain plane, said second portion extending inextricably along said insulating film between said certain plane and said other plane, and the thickness of said second section continuously decreases as the said second section approaches said light-receiving surface. 18. The photovoltaic conversion element according to any one of claims 1 to 3, in which a transparent film is provided, which has the same stoichiometric composition as said first portion, and extends from the top of said element to the top of said insulating film,
and wherein said transparent film includes
a first region inextricable with said second region, and
a second region inextricable with said first region,
and wherein said first region surrounds said second region within a plane parallel to said light receiving surface,
and wherein the refractive index of said first region is higher than the refractive index of said second region, or
the photoelectric conversion element according to any one of claims 4 to 6, wherein a transparent film is provided that has the same stoichiometric composition as said first portion and extends from the top of said element to the top of said insulating film,
and wherein said transparent film includes a first region made inextricably with said second region, and
a second region inextricable with said first region,
and wherein said first region surrounds said second region within a plane parallel to said light receiving surface,
and the refractive index of said first region is greater than the refractive index of said second region. 19. The photovoltaic conversion element according to any one of claims 1 to 6, in which there are many layers of electrical wiring mutually connected by a plug layer within said insulating film, and on the side of said portion of the photoelectric conversion opposite to said element, a first lens body layer is provided and a second layer of the lens body located between the first layer of the lens body and said element. 20. The photovoltaic conversion element according to claim 1 or 7, wherein the materials of said first portion and said second portion are silicon nitride or resin. 21. The photovoltaic conversion device, in which a plurality of pixels are arranged corresponding to the photovoltaic conversion elements according to claim 1 or 7, and the interval of axes passing through said first portion within said plane and said other plane perpendicular to said light receiving surface of each of the mutually adjacent photoelectric converting elements equal to or less than 5.0 microns. 22. A photovoltaic converting device in which a plurality of pixels are arranged corresponding to the photovoltaic converting elements of claim 8, and an interval of axes passing through said first portion within said certain plane and said other plane perpendicular to said light receiving surface of each of mutually adjacent photovoltaic converting elements is equal to or less than 5.0 microns. 23. A photovoltaic converting device in which a plurality of pixels are arranged corresponding to the photovoltaic converting elements of claim 10, and an interval of axes passing through said first portion within said said plane and said other plane perpendicular to said light receiving surface of each of mutually adjacent photovoltaic converting elements is equal to or less than 5.0 microns. 24. A photovoltaic converting device in which a plurality of pixels are arranged corresponding to the photovoltaic converting elements according to claim 12, and the interval of axes passing through said first portion within said certain plane and said other plane perpendicular to said light receiving surface of each of mutually adjacent photovoltaic converting elements is equal to or less than 5.0 microns. 25. A photovoltaic converting device in which a plurality of pixels are arranged corresponding to the photovoltaic converting elements according to claim 13, and the interval of axes passing through said first portion within said certain plane and said other plane perpendicular to said light receiving surface of each of mutually adjacent photovoltaic converting elements is equal to or less than 5.0 microns. 26. A photovoltaic converting device in which a plurality of pixels are arranged corresponding to the photovoltaic converting elements according to claim 17, and the interval of axes passing through said first portion within said certain plane and said other plane perpendicular to said light receiving surface of each of mutually adjacent photovoltaic converting elements is equal to or less than 5.0 microns. 27. A system for reading images containing
a photovoltaic conversion device in which a plurality of photovoltaic conversion elements according to claim 19 is arranged, and a signal processing device, to which a signal output from said photovoltaic conversion device is inputted, and where said signal is processed. 28. A system for reading images containing
a photoelectric conversion device in which a plurality of photoelectric conversion elements according to any one of claims 1 to 7 and 10 are arranged, and
a signal processing device where an electrical signal output from said photoelectric conversion device is inputted, and where said signal is processed.

Images