JPH029176A - Photoelectric conversion device and semiconductor device - Google Patents

Abstract

PURPOSE:To maintain high photoelectric conversion efficiency while preventing photoelectric conversion characteristics from deteriorating by a method wherein a light reflection layer is provided on the exterior of an electrode on the opposite side of a photoelectric conversion layer via a transparent insulation layer, and light is reflected by the light reflection layer and injected again in the photoelectric conversion element. CONSTITUTION:A plurality of photoelectric conversion elements PD are provided on a rear face of a transparent substrate 1. An element PD has a transparent electrode 3 on a light receiving face of a photoelectric conversion layer 2 and a transparent electrode 4 on its rear face. The conversion layer 2 consists of a first conductive type semiconductor layer 2a, an type-i semiconductor layer 2b, and a second conductive type semiconductor layer 2c. A light reflection layer 6 made of Al of Ag is formed via a transparent insulation layer 5 of an SiO2 film, for example. The reflection layer 6 reflects light which has transmitted through the device PD and injects it in the element PD again. This prevents the element PD characteristics from deteriorating, while maintaining high photoelectric conversion efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photoelectric conversion device and a semiconductor device.

[Conventional technology]

As a photoelectric conversion device, there is conventionally a device as shown in FIG.

In this photoelectric conversion device, a plurality of photoelectric conversion elements (for example, solar cells) PD... are connected to a substrate 101 via an insulating layer 105.
is placed above. Each photoelectric conversion element PD includes a transparent electrode 103 on the light receiving surface of the photoelectric conversion layer 102, and an electrode 104 having a light reflecting effect on the back surface. Photoelectric conversion layer 1
02 is composed of a semiconductor scrap 102a, an i-type semiconductor layer 102b, and a reverse conductivity type semiconductor R102c, and is a so-called p-type semiconductor layer 102c.
It has an in structure. Each photoelectric conversion element PD is connected in series in the same direction. The incident light extends so that the end of the transparent electrode 103 overlaps the end of the light reflective electrode 104 of the adjacent element PD, and each element PD is connected.
03, enters the photoelectric conversion layer 102 and causes a photoelectric conversion effect, and the light that has once passed through the photoelectric conversion layer 102 is also reflected by the electrode 104 and enters the photoelectric conversion layer 102 again, causing a photoelectric conversion effect. Therefore, photoelectric conversion efficiency is good. It is particularly effective for light in the long wavelength region.

[Problem to be solved by the invention]

However, such photoelectric conversion devices have a problem of deterioration of element characteristics.

The electrode 104 is formed using Al (aluminum) or Ag (silver) in order to have light reflectivity. When the electrode 104 is made of these materials, AA and A
g diffuses into the photoelectric conversion layer 102 and deteriorates the device characteristics.

On the other hand, in such a photoelectric conversion device, the photoelectric conversion element PD
The creation of arrays is also becoming popular. Therefore,
A photoelectric conversion device having a configuration suitable for such array formation is desired.

In the above photoelectric conversion device, the transparent electrode 103 and the back electrode 10
4 are made of different materials (electrode 103: 1n, O, etc., electrode 104: AN, Ag), the electrodes react with each other at the connection portion 106 between the photoelectric conversion elements PD, damaging the electrical connection state. Furthermore, if the electrode 104 is made of Al or Ag, the semiconductor layers 102a to 102c thereon
The electrode 104 is coated with the etchant used when forming the transparent electrode 103.
is easily damaged and difficult to apply wet micro-processing technology, making it difficult to mass-produce.

In view of the above circumstances, the present invention provides a photoelectric conversion device that can maintain high photoelectric conversion efficiency while preventing characteristic deterioration of photoelectric conversion elements, is suitable for forming an array of photoelectric conversion elements, and is easy to manufacture. and a semiconductor device.

[Means to solve the problem]

In order to solve the above problem, the photoelectric conversion device according to claim 1 is provided with a charging conversion element having transparent electrodes on the light-receiving surface and the opposite surface of the photoelectric conversion layer, and a transparent insulating layer is provided on the outside of the electrode on the opposite surface. A light-reflecting layer is provided, and the light-reflecting layer reflects the light that has once passed through the photoelectric conversion element and makes it enter the element again.

In the semiconductor device according to claim 2.3, the photoelectric conversion element having transparent electrodes on the light receiving surface and the opposite surface of the photoelectric conversion layer is provided on a light reflective electrode formed on the semiconductor substrate via a transparent insulating layer. The light-reflecting electrode reflects the light that has once passed through the photoelectric conversion element and makes it enter the element again.

In addition to the above, the semiconductor substrate is provided with a MOS transistor, and the transistor is controlled by the output of the photoelectric conversion element.

[For production]

Since a transparent electrode is used as the back electrode of the photoelectric conversion element instead of an electrode made of Aff or Ag, harmful substances will not diffuse into the photoelectric conversion layer from this electrode. Of course, a light-reflecting layer (light-reflecting electrode) is provided to increase photoelectric conversion efficiency, but this
Even if the transparent electrode or transparent insulating layer acts as a barrier and is made of harmful substances such as A4 or A4, which is harmful to the photoelectric conversion layer.
Prevent g from diffusing.

Furthermore, when connecting photoelectric conversion elements in an array, similar transparent electrodes are used to connect the elements, so it is important to avoid mutual reactions between the electrodes that could cause element deterioration. Can be suppressed.

Since a transparent insulating layer is formed on the light reflective electrode,
In the case where a photoelectric conversion element PD is layered on top of the photoelectric conversion element PD,
Even if wet micro-processing technology is applied, the transparent insulating layer acts as a protective film and prevents the light-reflecting electrode from being damaged. Furthermore, since the light-reflecting electrode also serves as a light-reflecting layer, there is no need to create a new light-reflecting layer, and the number of steps can be reduced.

When the semiconductor element is a MOS transistor, the photoelectric conversion element can be controlled without substantially consuming power.

〔Example〕

Hereinafter, examples of a photoelectric conversion device and a semiconductor device according to the present invention will be explained with reference to the accompanying drawings.

FIG. 1 shows an example of a photoelectric conversion device according to claim 1.

In this photoelectric conversion device, a plurality of photoelectric conversion elements (for example, photovoltaic elements) PD... are provided on the back surface of a transparent substrate l. Light enters from the surface of the transparent substrate 1. Each photoelectric conversion element PD has a transparent electrode 3 on the light-receiving surface of the photoelectric conversion layer 2, and a transparent electrode 4 on the back surface (opposite surface). Photoelectric conversion layer 2
are a first conductivity type (for example, P type) semiconductor layer 2a, an i-type semiconductor layer 2b, and a second conductivity type (for example, N type) semiconductor layer 2C.
This is a so-called pin structure. Each photoelectric conversion element PD is connected in series in the same direction. The ends of the transparent electrodes 4 extend so as to overlap the ends of the transparent electrodes 3 of adjacent elements, thereby connecting each element PD.

The transparent electrode 3.4 is made of, for example, Ir+z ○s, SnO
□, made of a transparent conductive material such as ITO (indium tin oxide). Of course, the electrodes 3.4 can be made of the same material, but a film that is easier to etch than the electrode 3 is used for the electrode 4. For example, formation conditions (temperature)
Even the same material can have different etching characteristics by changing the formation method (EB evaporation method and sputtering method).

In this photoelectric conversion device, a light reflecting layer 6 made of AA or Ag
is formed via a transparent insulating layer 5 such as a SiOz film.

This photoelectric conversion device is formed by laminating layers in order starting from the transparent electrode 3 (facing downward in the figure) up to the light reflecting layer 6.

The light-reflecting layer 6 is formed last, and the light-reflecting layer 6 is, for example, A! It can be easily provided by depositing or depositing Ag on the entire surface. This is because the transparent insulating layer 5 is formed thereon, and there is no risk of electrical short-circuiting between the photoelectric conversion elements PD. In the absence of the transparent insulation f'55, forming the light reflecting layer 6 on the entire surface will short-circuit the photoelectric conversion elements PD, so special measures and processes are required to prevent short-circuiting, and molding It takes time and effort. Even if a large number of photoelectric conversion elements PD are arranged in an array, the light reflection layer 6 can be easily formed.

FIG. 2 shows another embodiment of the photoelectric conversion device.

This photoelectric conversion device includes, for example, an insulating layer 17, a light reflecting layer 16, and a transparent insulating layer 15, which are laminated in this order on the surface of a substrate 11 on which a circuit is formed or which is conductive. A large number of photoelectric conversion elements (for example,
A photovoltaic element (PD) is provided.

Each photoelectric conversion element PD has a transparent electrode 13 on the light-receiving surface of the photoelectric conversion layer 12, and a transparent electrode 14 on the back surface (opposite surface). The photoelectric conversion layer 12 is of a second conductivity type (for example, N type)
It is composed of a semiconductor IFi 12a, an i-type semiconductor layer 12b, and a first conductivity type (for example, P-type) layer 12C, and has a so-called pin structure. Each photoelectric conversion element PD is connected in series in the same direction. Each element PD extends so that the end of the transparent electrode 13 overlaps the end of the transparent electrode 14 of an adjacent element.
are connected.

The materials of the transparent electrodes 13, 14, the light reflecting layer 16, and the transparent insulating layer 17 are the same as in the previous embodiment. Also, electrode 13.1
4 can be made of the same material, but the electrode 13 is made of a film that is easier to etch than the electrode 14.

In this photoelectric conversion device, the mold structure starts with the insulating layer 17 (upwards in the figure) and is sequentially laminated up to the transparent electrode 13.

Further, since the transparent insulating layer 15 is provided on the light reflection layer 16 for protection, there is no fear that the light reflection layer 16 will be damaged by the etchant when forming the element PD shadow.

1, one embodiment of the semiconductor device will be described.

FIG. 3 shows an example of a semiconductor device according to claim 2.3. FIG. 4 shows an equivalent circuit of this semiconductor device.

This semiconductor device includes an array DA in which an MOS transistor T and a plurality of photovoltaic elements PD are connected in series in the same direction, and the output voltage induced in the array DA is applied to the gate of a MOS transistor T'. It is now possible to join the In other words, the photovoltaic element array DA allows MO
The MOS transistor T, in which the switching of the S transistor T is controlled, consists of a plurality of MO3I transistor units TU connected in parallel. Each unit TU has a source region 32 and a drain region 33 on the semiconductor substrate 21 -, and a channel region 34 between both head regions 3233 .

Furthermore, this MOS transistor unit TU has an insulated gate electrode 36 made of polysilicon on the channel region 34 with an insulating film 35 interposed therebetween. An insulating layer 35a also serving as a protective film is formed on the gate electrode 36. Each gate electrode 36 is electrically connected together in a place that cannot be seen in the figure.

The P'' layer where the channel region 34 is located and the N'' layer which is the source region 33 are so-called double-diffused impurity regions. Therefore, this transistor T has a high withstand voltage of 4. It has a D-MO3 structure suitable for high-speed operation. In the transistor T of this D-MO3 structure, the channel length is the same as that of the P' layer and N''
It is defined by the difference in diffusion of the eyebrows, and can be shortened without using photolithography technology. Further, the drain electrode 139 is located on the back side of the semiconductor substrate 21, and therefore the transistor T also has a vertical structure. Note that 40 is a guard ring area.

As shown in FIG. 3, the source electrode 38 is formed between each transistor unit TU, and for example,
A light reflective material such as Aβ is used.

A photovoltaic element (solar cell) PD is provided on the source electrode 38 via a transparent insulating layer 25 such as a SiOg film. Each photovoltaic element PD has a photovoltaic layer 2
2 has a transparent electrode 23 on the light receiving surface, and a transparent electrode 24 on the back surface.
have. The photovoltaic layer 22 includes a second conductivity type (for example, N type) semiconductor layer 22a, an i-type semiconductor layer 22b, and a first conductivity type semiconductor layer 22a.
It is composed of a conductive type (for example, P type) layer 22c, and has a so-called pin structure. Each photovoltaic element PD is connected in series in the same direction. The ends of the transparent electrodes 23 extend so as to face the ends of the transparent electrodes 24 of adjacent elements, and the elements PD are connected to each other.

The connection between the array DA and the MO5I-transistor T is such that the conductive layer 24' formed at the same time as the transparent electrode 24 is connected to the source electrode 3.
8, an extension part 24'' extending from the transparent electrode 24 at the left end in the figure is connected to a conductive layer 38' which is in contact with the gate electrode 36.
28 is a transparent insulating layer for protection.

In this semiconductor device, since the source electrode 38 also serves as a light reflective layer, the formation of a light reflective layer can be omitted.

In this semiconductor device, a transistor T is provided on a semiconductor substrate 21.
After forming, transparent insulation J525 is laminated, and then,
The photovoltaic device PD is laminated in order starting from the electrode 24 and ending with the electrode 23 (looking upward in the figure). therefore,
Since the electrode 38 is protected by the transparent insulating layer 28, there is no risk that the electrode 38 will be damaged by the etchant used when forming the photovoltaic element PD.The transparent insulating layer 28 is the last layer laminated. Then, the semiconductor device is completed.

The materials of the transparent electrodes 23, 24 and the transparent insulating layer 25 are the same as in the above embodiment. It should be noted that a film that is more easily etched than the transparent electrode 24 is used for the -transparent heavy state 23.

Note that, as is common in the above examples, the photoelectric conversion layer (
Although amorphous silicon or the like is used for the photovoltaic layer (photovoltaic layer), it is not limited thereto.

This invention is not limited to the above embodiments. The photoelectric conversion equipment or semiconductor device may include only one photoelectric conversion element. Photoelectric conversion layer, transparent electrode, or light reflective layer (
The light-reflecting electrode) may be formed of materials other than those exemplified above, and may not be made of pin material.

〔Effect of the invention〕

As described above, in the photoelectric conversion device and semiconductor device according to the present invention, harmful substances are diffused into the photoelectric conversion layer from the light reflective layer (light reflective electrode) while maintaining high photoelectric conversion efficiency. The light receiving sensitivity and reliability are high.

In addition, even when arrayed, the reliability of connections between photoelectric conversion elements can be improved, and assembly is easy and highly practical.

[Brief explanation of the drawing]

1 and 2 are respectively cross-sectional views of an example of a photoelectric conversion device of the present invention, FIG. 3 is a cross-sectional view of an example of a semiconductor device of the present invention, and FIG. 4 is a cross-sectional view of an example of a semiconductor device of the present invention. FIG. 5, an equivalent circuit diagram of the device, is a cross-sectional view of an example of a conventional photoelectric conversion device. PD...Photoelectric conversion element T...MOS transistor 3.13.23...Transparent electrode on light receiving surface 41
4.24...Transparent electrode on the opposite side 5.15.25.
・Transparent insulating layer 6.16 ・Light reflective layer 38・
・・Light reflective electrode substrate (source electrode)

Claims (1)

[Scope of Claims] A photoelectric conversion element having transparent electrodes is provided on the light receiving surface and the opposite surface of one photoelectric conversion layer, respectively, and a light reflecting layer is provided on the outside of the electrode on the opposite surface with a transparent insulating layer interposed therebetween. . A photoelectric conversion device, wherein the light reflecting layer reflects the light that has once passed through the photoelectric conversion element and makes it enter the element again. A photoelectric conversion element having transparent electrodes on the light-receiving surface and the opposite surface of two photoelectric conversion layers is provided on a light-reflecting electrode formed on a semiconductor substrate via a transparent insulating layer, and the light-reflecting electrode is . A semiconductor device in which light that has once passed through the photoelectric conversion element is reflected and made to enter the same element again. 3. The semiconductor device according to claim 2, wherein the semiconductor substrate is provided with a MOS transistor, and the transistor is controlled by the output of the photoelectric conversion element.