CN111628033B - Method for manufacturing photoelectric detection device - Google Patents

Abstract

The application discloses a manufacturing method of a photoelectric detection device, which comprises the following steps: growing an epitaxial layer on the prepared first substrate, and forming a first doped region, a second doped region and a third doped region on one side, far away from the first substrate, of the epitaxial layer, wherein the second doped region is positioned between the first doped region and the third doped region; forming a reflective structure over one side of the epitaxial layer; processing the first substrate to expose the other side of the epitaxial layer; doping the other side to form a fourth doped region; and preparing a first bonding pad, a second bonding pad and a third bonding pad which are respectively connected with the first doping region, the second doping region and the third doping region below the fourth doping region so as to obtain corresponding electrodes. By utilizing the technical scheme provided by the application, a device suitable for detecting photons with longer wavelength can be provided.

Description

Manufacturing method of photoelectric detection device

Technical field

The present application relates to the field of semiconductor technology, and in particular to a method of manufacturing a photoelectric detection device.

Background technique

The description in this section only provides background information related to the disclosure of the present application and does not constitute prior art.

Low-flux photon detection technology is a photon detection technology that can detect light signals with lower light flux density (for example, 10 ^-19 ~ 10 ^-6 W/mm ² ), which can be applied to many fields, such as medical imaging ( In particular, key areas include positron emission tomography (PET), homeland security, high-energy physics experiments and other imaging.

In the field of low-flux photon detection technology, silicon photomultipliers (SiPM) have high detection efficiency, excellent single-photon response and resolution capabilities, small size, easy integration, low operating voltage, and are not susceptible to It has attracted great attention in recent years due to its many advantages such as magnetic field interference, good reliability, and low cost. At present, silicon photomultipliers are mainly manufactured in the following ways: (1) forming a P-type epitaxial layer on a wafer as a substrate; (2) forming a deep N-well (DNW) on the P-type epitaxial layer and forming a deep N-well (DNW) in the middle of the DNW and Multiple N wells (NWELL) are formed at the edge; (3) P wells (PWELL) are formed outside the outermost N well; (4) P+ type doped regions are formed above the middle NWELL and above the NWELL at the edge. N+ type doped region; (5) A shallow trench isolation region (STI) is formed between each P+ type doped region and N+ type doped region, in which the formed P well (PWELL) and P+ type doped region The electrodes that make up the silicon photomultiplier. The silicon photomultiplier manufactured using the above method is shown in Figure 1.

In the process of implementing this application, the inventor discovered that there are at least the following problems in the prior art:

The PN junction in silicon photomultipliers manufactured using existing methods generally consists of a high-concentration P (or N)-type doped region close to the surface of the silicon material and a lower-doped N (or P) well located below it. The junction depth is shallow and the depletion region width is narrow, so the detection efficiency of blue-violet light with shorter wavelength is higher, but the detection efficiency of photons with longer wavelength (such as red light and near-infrared light) is low.

Contents of the invention

The purpose of the embodiments of the present application is to provide a method for manufacturing a photoelectric detection device, so as to provide a device suitable for detecting photons with longer wavelengths.

In order to solve the above technical problems, embodiments of the present application provide a method for manufacturing a photoelectric detection device. The method may include:

Grow an epitaxial layer on the prepared first substrate, wherein both the epitaxial layer and the first substrate are of a first conductivity type;

A first doping region and a second doping region of a second conductivity type opposite to the first conductivity type are formed on a side of the epitaxial layer away from the first substrate and are in the first conductivity type. A third doped region of conductivity type, wherein the second doped region is located between the first doped region and the third doped region, and the first doped region and the first doped region The first region in the substrate and the epitaxial layer corresponding to the first doped region constitutes a first photosensitive element, and the second doped region and the first region in the first substrate and the epitaxial layer The second region corresponding to the second doped region constitutes a second photosensitive element;

Form a reflective structure corresponding to the first photosensitive element above the side of the epitaxial layer;

processing the first substrate to expose another side of the epitaxial layer opposite to the one side;

Perform a doping process on the other side of the epitaxial layer to form a fourth doped region of the first conductivity type;

A first bonding pad, a second bonding pad and a third bonding pad respectively connected to the first doping region, the second doping region and the third doping region are prepared below the fourth doping region. a soldering pad, wherein the first soldering pad constitutes a first electrode used as an output end of the photoelectric detection device, the second soldering pad constitutes a second electrode of the photoelectric detecting device, and the third soldering pad Constituting the third electrode of the photoelectric detection device.

Optionally, the step of forming the first doped region, the second doped region and the third doped region includes:

A first active area, a second active area and a third active area on the outer surface of the epitaxial layer away from the first substrate are determined, wherein the second active area is located on the between the first active area and the third active area;

Using a preset process, a second dopant is doped into the epitaxial layer from the first active region and the second active region to form the first doped region and the second doped region. , and use the preset process to dope a first dopant into the epitaxial layer from the third active region to form the third doped region.

Optionally, the preset process includes an ion implantation process or a diffusion doping process.

Optionally, the step of forming the reflective structure includes:

depositing a first passivation layer on the side of the epitaxial layer;

forming a reflective region on the first passivation layer at a position corresponding to the first doped region;

After forming the reflective region, a second passivation layer is deposited on the first passivation layer, wherein the first passivation layer and the second passivation layer in which the reflective region is formed constitute Describe the reflective structure.

Optionally, before forming the reflective area, the method further includes:

A plurality of first metal interconnection lines respectively connected to the first doping region and the second doping region are formed in the first passivation layer, and in the plurality of first metal interconnection lines A first through hole filled with a first metal is formed below, penetrating the first passivation layer and the epitaxial layer.

Optionally, the steps of preparing the first bonding pad, the second bonding pad and the third bonding pad include:

A third passivation layer is deposited under the fourth doped region, and filling is formed in the third passivation layer at positions corresponding to the first doped region and the first through hole. There is a second through hole of the first metal, wherein the second through hole formed at a position corresponding to the first through hole is connected to the first through hole;

forming a second metal interconnection line below the formed second through hole;

depositing a fourth passivation layer under the third passivation layer in which the second metal interconnection line is formed, and etching the fourth passivation layer to expose the first metal interconnection line A part of the structure, wherein the second metal interconnection lines exposed at positions corresponding to the first doped region, the second doped region and the third doped region respectively form the third A bonding pad, the second bonding pad and the third bonding pad.

Optionally, the method also includes:

Quenching elements connected to the first photosensitive element and the second photosensitive element respectively are prepared above the side of the epitaxial layer.

Optionally, the step of preparing the quenching element includes:

depositing polysilicon on a specific area on the side of the epitaxial layer, and etching and doping the polysilicon to obtain the quenching element;

A third through hole filled with the first metal is formed above the quenching element to connect with the first metal interconnection line.

Optionally, the method also includes:

An isolation region is formed in the epitaxial layer on a side away from the substrate to separate the first doped region, the second doped region and the third doped region.

Optionally, the step of forming the isolation area includes:

An inactive region on the outer surface of the epitaxial layer away from the first substrate is etched to form a trench. The inactive region is located between the first doped region and the first doped region. Between multiple active regions in the three-doped region;

A specific material is filled into the trench to form the isolation region.

Optionally, before forming the first to third doped regions, the method further includes:

A buried layer of the first conductivity type is formed in the first region and/or the second region.

Optionally, before forming the first to third doped regions, the method further includes:

A first well region, a second well region and/or a third well region respectively corresponding to the first doped region, the second doped region and/or the third doped region are formed in the epitaxial layer. well region.

Optionally, before processing the first substrate, the method further includes:

The reflective structure is bonded to the prepared second substrate.

Optionally, the method also includes:

A convex lens is prepared below the fourth doped region at a position corresponding to the first photosensitive element and/or the second photosensitive element.

It can be seen from the technical solutions provided by the above embodiments of the present application that the embodiments of the present application form a first doped region of the second conductivity type, a second doped region of the second conductive type and a second doped region on the side of the epitaxial layer away from the first substrate. A third doped region of the first conductivity type, wherein the second doped region is located between the first doped region and the third doped region, which causes the first doped region and the third doped region to be doped by the second The impurity regions are spaced apart, and only the first pad connected to the first doping region is used as the output end of the photodetection device. Therefore, compared with the case where the first doping region and the third doping region are adjacent, this So that when the manufactured photoelectric detection device is in working state, the width of the depletion region in the PN junction formed inside the first photosensitive element can be increased, and the influence of the internal noise of the device on the PN junction can be reduced, thereby The detection efficiency of photons with longer wavelengths can be improved, and by forming a reflective structure above the side of the epitaxial layer at a position corresponding to the first doped region, it is possible to detect photons passing through the first doped region. The photons are reflected, thereby further improving the photon detection efficiency.

Description of the drawings

In order to explain the embodiments of the present application or the technical solutions in the prior art more clearly, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are only These are some of the embodiments recorded in this application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without exerting any creative effort.

Figure 1 is a schematic structural diagram of a silicon photomultiplier in the prior art;

Figure 2 is a flow chart of a manufacturing method of a photoelectric detection device provided by an embodiment of the present application;

Figure 3 is a schematic diagram of a partial structure of a photoelectric detection device obtained using the manufacturing method in Figure 2;

Figure 4 is a flow chart of another method of manufacturing a photoelectric detection device provided by an embodiment of the present application;

FIG. 5 is a schematic diagram of a partial structure of a photoelectric detection device obtained by using the manufacturing method in FIG. 4 .

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only used to explain some of the embodiments of the present application, not all of them. Examples are not intended to limit the scope or claims of this application. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts should fall within the scope of protection of this application.

It should be noted that when an element is referred to as being "disposed on" another element, it can be directly located on the other element or intervening elements may also be present. When an element is referred to as being "connected/coupled" to another element, it can be directly connected/coupled to the other element or intervening elements may also be present. As used herein, the term "connected/coupled" may include electrical and/or mechanical physical connections/couplings. The term "comprises" as used herein refers to the presence of features, steps or elements but does not exclude the presence or addition of one or more other features, steps or elements. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. The terms "upper" and "lower", "upper" and "lower" used in this article are only relative concepts. Depending on different viewing directions or placement positions, upper or upper may also refer to lower or lower respectively, and vice versa.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

In the description of this application, the terms "first", "second", "third", etc. are only used for descriptive purposes and to distinguish similar objects. There is no order between them, and they cannot be understood as indicating or implies relative importance. Furthermore, in the description of the present application, unless otherwise stated, the meaning of “plurality” is two or more.

In the description of this application, the first conductivity type may refer to P-type doping, which mainly relies on holes to conduct electricity, and the second conductivity type may refer to N-type doping, which mainly relies on electrons to conduct electricity. Alternatively, the first conductivity type Type may refer to N-type doping, and the second conductivity type may refer to P-type doping. In addition, “P+” and “P-” may respectively refer to relatively higher and lower doping concentrations compared to the doping concentration of the P-type doping region, and “N+” and “N-” may refer to respectively Relatively higher and lower doping concentrations compared to the doping concentration of the N-type doped region, for example, the doping concentrations of the P+-type and N+-type doped layers/regions can be 1x10 ¹⁹ ~ 1x10 ²¹ cm ^-3 , The doping concentration of the P-type and N-type doped layers/regions can be 1x10 ¹⁶ ~ 1x10 ¹⁸ cm ^-3 . Unless otherwise stated, doped regions or doped layers with the same conductivity type may have the same or different doping concentrations, and doped regions or doped layers with different conductivity types may also have the same or different doping concentrations. impurity concentration.

The manufacturing method of the photoelectric detection device for photon detection provided by the embodiment of the present application will be described in detail below with reference to the accompanying drawings.

As shown in Figures 2 and 3, one embodiment of the present application provides a method for manufacturing a photoelectric detection device, which may include the following steps:

S1: Grow an epitaxial layer on the prepared first substrate.

After using the first dopant to prepare the first substrate having the first conductivity type (for example, P type), the first dopant may be used to grow a layer on the outer surface of the first substrate that is consistent with the first substrate. The epitaxial layer has the same conductivity type, that is, the epitaxial layer and the first substrate both have the first conductivity type, but the doping concentration in the formed epitaxial layer may be lower than the doping concentration in the first substrate. Regarding how to prepare the substrate and the method of growing the epitaxial layer on the outer surface of the substrate, reference can be made to the existing technology, which will not be described again here.

S2: Form a first doping region and a second doping region of a second conductivity type opposite to the first conductivity type and a third doping region of the first conductivity type on a side of the epitaxial layer away from the first substrate. Miscellaneous area.

After the epitaxial layer is grown on the first substrate, a first doping region of a second conductivity type opposite to the first conductivity type and a second doping region may be formed on a side of the epitaxial layer away from the first substrate. region and a third doped region of the first conductivity type. As shown in FIG. 3 , the formed first doped region, the first substrate and the first region in the epitaxial layer corresponding to the first doped region (that is, the region below the first doped region) may be constituted by The first photosensitive element for detecting photons, the formed second doped region, the first substrate and the second region in the epitaxial layer corresponding to the second doped region (ie, the region below the second doped region ) constitutes a second photosensitive element for detecting photons.

You can perform this step by following the following procedure:

First, regions for forming doping regions, that is, a plurality of active regions, on the outer surface of the epitaxial layer away from the first substrate can be determined. The plurality of active areas may include a first active area, a second active area, and a third active area. Wherein, the second active area is located between the first active area and the third active area. For example, the middle partial area on the outer surface of the epitaxial layer can be determined as the first active area, the edge areas on both sides of the outer surface of the epitaxial layer can be determined as the third active area, and the first active area and Partial areas between the third active areas are determined as second active areas, but are not limited to these locations. In addition, the number, size and specific position of the first active region, the second active region and the third active region can be determined according to the size of the epitaxial layer and combined with actual needs, or can also be determined according to the wells formed in the epitaxial layer. area and/or buried layer.

Then, a second dopant may be doped into the epitaxial layer from the determined first active region and the second active region using a preset process to form a first conductivity type of a second conductivity type opposite to the first conductivity type. a doped region and a second doped region, and a first dopant can be doped into the epitaxial layer from the determined third active region using a preset process to form a third doped region of the first conductivity type. The doping concentration and depth of the formed first doped region, the second doped region and the third doped region can be determined according to actual needs, but the doping concentrations of the three can all be higher than the doping concentration of the epitaxial layer. . The preset process may be an ion implantation process or a diffusion doping process, but is not limited to these two processes. For detailed descriptions of these two processes, reference can be made to the relevant descriptions in the prior art and will not be repeated here.

In addition, an area between a plurality of active areas may be determined as an inactive area. That is to say, the outer surface of the epitaxial layer consists of passive areas and active areas.

S3: Form a reflective structure corresponding to the first photosensitive element above the side of the epitaxial layer.

After forming the first doped region, a reflective structure may be formed over the side of the epitaxial layer. Specifically, a first passivation layer may be deposited on one side of the epitaxial layer, and then a reflective region may be formed on the first passivation layer at a position corresponding to the first doped region, for example, by depositing A metal material with a higher reflectivity or a dielectric material with a multi-layer structure is used to form a reflective region. Finally, a second passivation layer can be deposited on the first passivation layer, wherein the first passivation layer with the reflective region and The second passivation layer forms a reflective structure.

By utilizing the reflective structure, photons incident on the lower side of the photodetection device and passing through the first doped region can be reflected, thereby improving the photon detection efficiency.

In addition, before forming the reflective area, the method may also include:

A plurality of first metal interconnection lines respectively connected to the first doping region and the second doping region are formed in the first passivation layer, and a penetrating first passivation line is formed under the plurality of first metal interconnection lines. A plurality of first through holes of the first metal are filled in the epitaxial layer and the epitaxial layer. Specifically, it can be at a position on the first passivation layer above the edges on both sides of the first doped region and the second doped region and/or above the gap between adjacent doped regions and below the reflective region. Etching is performed to form a first through hole, and a first metal (for example, tungsten, but not limited to this) is filled into the first through hole; and then first metal interconnection lines are respectively formed above the plurality of first through holes. ; Then, a first via hole penetrating the first passivation layer and the epitaxial layer may be formed under each first metal interconnection line, and the first metal may be filled into the formed first via hole. The formed first through hole filled with the first metal forms a connection channel between the first doped region and the second doped region and the subsequently formed corresponding pad.

S4: The first substrate is processed to expose the other side of the epitaxial layer.

After the first to third doped regions are formed on the epitaxial layer, a side of the first substrate facing away from the epitaxial layer may be processed to expose the first to third doped regions in the epitaxial layer. One side of the third doped region is opposite the other side.

Regarding the specific method of processing the first substrate to expose the other side of the epitaxial layer, reference may be made to related processes in the prior art, which will not be described again here.

S5: Perform doping treatment on the other side of the epitaxial layer to form a fourth doped region of the first conductivity type.

After the other side of the epitaxial layer is exposed, a preset process such as an ion implantation process can be used to inject a first dopant into the epitaxial layer from the other side to form a fourth doping region of the first conductivity type. The doping concentration of the doped region is higher than that of the epitaxial layer.

The formed fourth doped region can be used to replace the first substrate, and corresponding regions therein can become part of the first photosensitive element and the second photosensitive element.

S6: Form a first bonding pad, a second bonding pad and a third bonding pad respectively connected to the first doping region, the second doping region and the third doping region under the fourth doping region.

After the first doping region, the second doping region and the third doping region are formed, the first doping region, the second doping region and the third doping region may be formed under the fourth doping region. The first bonding pad, the second bonding pad and the third bonding pad are connected, and the first bonding pad and the first doping region, the second bonding pad and the second doping region, and the third bonding pad and the third doping region are formed. Metal interconnect lines between areas. This step may be specifically performed as follows: a third passivation layer may be deposited below the fourth doped region, at a position below the third doping region and a position corresponding to the first through hole in the third passivation layer. A second through hole is formed, wherein the first through hole penetrating the first passivation layer and the epitaxial layer is connected to the corresponding second through hole formed on the third passivation layer, that is, this second through hole is formed from the second through hole. The formation position penetrates the third passivation layer and the fourth doping region to communicate with the first through holes, and then fills the first metal into the formed second through holes, and then forms a plurality of third through holes under these second through holes. two metal interconnect lines, a fourth passivation layer may then be deposited beneath the third passivation layer, and the fourth passivation layer may be etched to expose a portion of each second metal interconnect line, after being doped with the first The second metal interconnection lines exposed in the regions corresponding to the impurity region to the third doping region respectively constitute the first to third pads. These first through holes and second through holes filled with the first metal and The first metal interconnection line and the second interconnection line realize the connection between each doped region and the corresponding pad.

In addition, a plurality of third passivation layers, second metal interconnect lines and fourth passivation layers may be deposited under the fourth doping region according to the number of the first doped regions and the second doped regions. composed of stacked layers.

In addition, the first soldering pad may constitute a first electrode serving as an output terminal of the photoelectric detection device, and the second soldering pad may constitute a second electrode of the photoelectric detecting device, the polarity of which is the same as that of the first electrode, for example, both Being the cathode, the third pad may constitute a third electrode of the photodetection device, and its polarity is opposite to the first electrode and the second electrode, for example, it is the anode. In practical applications, by applying voltage to the first electrode, the second electrode and the third electrode, the photodetection device can be caused to measure photons emitted from the target object, and according to the measurement result output by the first electrode, the photodetection device can be determined The number of photons measured by the device.

In another embodiment of the present application, as shown in Figures 4 and 5, before step S2, the method may further include the following steps:

S11: Form a buried layer of the first conductivity type corresponding to the first doped region and/or the second doped region in the epitaxial layer.

Before forming the first doped region and/or the second doped region in the epitaxial layer, a buried layer of a first conductivity type (for example, a P-type buried layer or an N-type buried layer) may be formed in the epitaxial layer. The layer may be located beneath the first doped region and/or the second doped region. That is to say, at least one buried layer is first formed in the epitaxial layer, and then the first doped region and/or the second doped region may be formed above the buried layer. Regarding the specific manner of forming the buried layer in the epitaxial layer, reference may be made to the relevant descriptions in the prior art, which will not be described again here.

By forming a buried layer under the first doped region and/or the second doped region, the width of the depletion region in the PN junction within the first photosensitive element and the second photosensitive element can be increased, thereby increasing the photon absorption depth. range and photon detection efficiency.

In another embodiment of the present application, as shown in Figures 4 and 5, before step S2, the method may further include the following steps:

S12: Form a first well region, a second well region and/or a third well region respectively corresponding to the first doping region, the second doping region and/or the third doping region in the epitaxial layer.

Before forming the first doped region, the second doped region and the third doped region on one side of the epitaxial layer, the first well region, the second well region and/or the first well region may be formed at preset positions in the epitaxial layer. or third well region. Wherein, these well regions may be located outside the first doping region, the second doping region and/or the third doping region, and may respectively surround the first doping region, the second doping region and/or the third doping region. at least part of the complex area. specifically:

After determining the positions on the epitaxial layer where the first doping region, the second doping region and the third doping region are to be formed, the first doping region inside the epitaxial layer and the to-be-formed first doping region can be determined based on the determined positions. The first preset position, the second preset position and/or the third preset position corresponding to the positions of the region, the second doped region and/or the third doped region.

Then, the first well region, the second well region and/or the third well region corresponding to the first doping region, the second doping region and/or the third doping region may be respectively formed at these preset positions. Specifically, first ions may be implanted from the first active region and/or the second active region to the first preset position and/or the second preset position in the epitaxial layer to form the first well region and/or the second preset position in the epitaxial layer. Or the second well region, for example, N well, may also perform second ion implantation from the third active region to a third predetermined position in the epitaxial layer to form a third well region, for example, P well. Wherein, the doping concentration of the first well region and the second well region may be the same, but both are lower than that of the first doping region and the second doping region; the doping concentration of the third well region may also be lower than The doping concentration of the third doped region.

In addition, the first preset position to the third preset position can also be determined in advance, and then corresponding well regions are respectively formed at these preset positions, and the first doping region and the second doping region are determined based on the formed well regions. The location of the doped region and the third doped region.

By forming the first well region and the second well region, the first doped region and the second doped region can be protected respectively. By forming the third well region, the connection between the third doped region and the substrate can be enhanced. Conductivity.

It should be noted that step S12 can be executed before or after step S11. Although FIG. 5 shows that the buried layer is below the well region, in fact, the buried layer can also be between adjacent well regions, and there is no limitation here.

In another embodiment of the present application, as shown in Figures 4 and 5, before step S2, the method may further include the following steps:

S13: Form an isolation region for separating the first doped region, the second doped region and the third doped region on a side of the epitaxial layer away from the substrate.

Before forming the first doped region, the second doped region and the third doped region on the side of the epitaxial layer, inactive regions on the outer surface may first be determined and then formed on the inactive regions. quarantine area. Specifically, at least one passive region may be etched to form a trench, and a specific material (eg, oxide or nitride) may be filled into the trench, so that an isolation region (eg, STI) may be formed. The formed isolation region can be directly coupled or separated from the corresponding doped region, thereby improving electrical performance or reducing noise. Correspondingly, in step S2, the position of the active area can be determined according to the position of the inactive area. For example, the area between multiple inactive areas can be determined as the active area, and then an area can be formed on the active area. corresponding doped region.

In another embodiment of the present application, as shown in Figures 4 and 5, before step S3, the method may further include the following steps:

S21: Prepare quenching elements respectively connected to the first photosensitive element and the second photosensitive element above the side of the epitaxial layer.

The quenching element may refer to the following element: when the first photosensitive element and the second photosensitive element produce a certain physical phenomenon (for example, avalanche breakdown phenomenon) due to the detection of a large number of photons, the first photosensitive element and the second photosensitive element Quenching is performed to restore the normal detection capabilities of the first photosensitive element and the second photosensitive element. The quenching element can be a resistor or a field effect transistor, and when the quenching element is a resistor, it can be located above the passive region (or isolation region), and when the quenching element is a field effect transistor, it can be located on the first above both edges of the active area and the second active area. At this time, the first photosensitive element and the second photosensitive element may be single photon avalanche diodes, and the photodetection device may be a back-illuminated silicon photomultiplier.

After obtaining the first photosensitive element and the second photosensitive element by forming the first to third doped regions on one side of the epitaxial layer, the first photosensitive element and the second photosensitive element can be prepared above the side The quenching element corresponding to the element. Specifically, polysilicon can be deposited in a specific area on one side of the epitaxial layer, and the deposited polysilicon can be etched, doped, etc., to obtain a quenching element. The specific area may be located above both side edges of the first active area and the second active area (not shown), or may be located above an inactive area (or isolation area) on the outer surface of the epitaxial layer.

Regarding the specific process of etching and doping polysilicon, reference may be made to relevant descriptions in the prior art.

Then, a third through hole filled with the first metal may be formed above the quenching element, through which the third through hole may be in ohmic contact with the first metal interconnection line, thereby achieving connection with the corresponding first doping region or the second Connection of doped areas.

It should be noted that, although not shown in the figure, a plurality of branches composed of quenching elements, corresponding first doped regions, and first metal interconnection lines connecting the two pass through them. The first metal interconnection lines are connected in parallel and connected to the first pad via the second metal interconnection line.

In another embodiment of the present application, as shown in Figures 4 and 5, before step S4, the method may further include the following steps:

S31: Bond the reflective structure to the prepared second substrate.

After the reflective structure is formed, the reflective structure may be bonded to another prepared substrate (ie, the second substrate). Specifically, the second passivation layer in the reflective structure is bonded to the second substrate, so that the second substrate can support all components including the reflective structure, the first photosensitive element, the second photosensitive element, etc.

In another embodiment of the present application, after step S6, the method may further include the following steps (not shown in the figure):

S61: Prepare a convex lens at a position corresponding to the first photosensitive element and/or the second photosensitive element under the fourth doped region.

After the fourth doped region is formed, a convex lens can be prepared below the fourth doped region at a position corresponding to the first photosensitive element and/or the second photosensitive element to condense light, so that the first photosensitive element and/or the second photosensitive element can be improved. Photon detection efficiency of the second photosensitive element.

The center of the prepared convex lens can be aligned with the center of the first photosensitive element or the second photosensitive element, its optical path can avoid the first metal interconnection line, and when the photoelectric detection device is also provided with a quenching element, its optical path Quenching elements can also be avoided.

Regarding how to prepare a convex lens, reference can be made to the description in the prior art.

It can be seen from the above description that in the embodiment of the present application, a first doped region of the second conductivity type, a second doped region and a second doped region located on the side of the epitaxial layer away from the first substrate are formed. The third doped region on the outside is of the first conductivity type, which causes the first doped region and the third doped region to be separated by the second doped region, and only the first solder connected to the first doped region is The disk serves as the output end of the photodetection device, so compared with the situation where the first doping region and the third doping region are adjacent, this makes it possible to increase the output of the first doping region when the resulting photodetection device is in the working state. The width of the depletion region in the PN junction formed inside the photosensitive element can reduce the impact of device internal noise on the PN junction, thereby improving the detection efficiency of longer wavelength photons. Furthermore, by forming a reflective structure above one side of the epitaxial layer at a position corresponding to the first doped region, photons passing through the first doped region can be reflected, thereby further improving the photon detection efficiency.

It should be noted that only a part of the photodetection device is shown in FIGS. 3 and 5 , and the other part may be symmetrical to the shown part, and the components shown in the figures (for example, the first photosensitive element and the The number of two photosensitive elements) is only illustrative, and the photoelectric detection device may include more first photosensitive elements and second photosensitive elements.

The systems, devices, modules, units, etc. explained in the above embodiments may be implemented by chips and/or entities (for example, discrete components), or by products with certain functions. For the convenience of description, when describing the above device, the functions are divided into various layers and described separately. Of course, when implementing the embodiments of the present application, the functions of each layer can be integrated into one or more chips.

Although the present application provides components as described in the above embodiments or drawings, more or fewer components may be included in the device based on routine or without creative efforts.

Although this application provides method operation steps as described in the above embodiments or flow charts, more or fewer operation steps may be included in the method based on routine or without creative effort. In steps where there is no necessary causal relationship logically, the execution order of these steps is not limited to the execution order provided by the embodiments of the present application.

Each embodiment in this specification is described in a progressive manner. The same and similar parts between the various embodiments can be referred to each other. Each embodiment focuses on its differences from other embodiments.

The above embodiments are described to facilitate understanding and use of the present application by those of ordinary skill in the technical field. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without inventive efforts. Therefore, this application is not limited to the above embodiments. Based on the disclosure of this application, improvements and modifications made by those skilled in the art without departing from the scope of this application should be within the protection scope of this application.

Claims (14)

1. A method of manufacturing a photoelectric detection device, characterized in that the method includes: Grow an epitaxial layer on the prepared first substrate, wherein both the epitaxial layer and the first substrate are of a first conductivity type; A first doping region and a second doping region of a second conductivity type opposite to the first conductivity type are formed on a side of the epitaxial layer away from the first substrate and are in the first conductivity type. A third doped region of conductivity type, wherein the second doped region is located between the first doped region and the third doped region, and the first doped region and the first doped region The first region in the substrate and the epitaxial layer corresponding to the first doped region constitutes a first photosensitive element, and the second doped region and the first region in the first substrate and the epitaxial layer The second region corresponding to the second doped region constitutes a second photosensitive element; Form a reflective structure corresponding to the first photosensitive element above the side of the epitaxial layer; processing the first substrate to expose another side of the epitaxial layer opposite to the one side; Perform a doping process on the other side of the epitaxial layer to form a fourth doped region of the first conductivity type; A first bonding pad, a second bonding pad and a third bonding pad respectively connected to the first doping region, the second doping region and the third doping region are prepared below the fourth doping region. a soldering pad, wherein the first soldering pad constitutes a first electrode used as an output end of the photoelectric detection device, the second soldering pad constitutes a second electrode of the photoelectric detecting device, and the third soldering pad Constituting the third electrode of the photoelectric detection device. 2. The method according to claim 1, wherein the step of forming the first doped region, the second doped region and the third doped region includes: A first active area, a second active area and a third active area on the outer surface of the epitaxial layer away from the first substrate are determined, wherein the second active area is located on the between the first active area and the third active area; Using a preset process, a second dopant is doped into the epitaxial layer from the first active region and the second active region to form the first doped region and the second doped region. , and use the preset process to dope a first dopant into the epitaxial layer from the third active region to form the third doped region. 3. The method of claim 2, wherein the preset process includes an ion implantation process or a diffusion doping process. 4. The method of claim 1, wherein the step of forming the reflective structure includes: depositing a first passivation layer on the side of the epitaxial layer; forming a reflective region on the first passivation layer at a position corresponding to the first doped region; After forming the reflective region, a second passivation layer is deposited on the first passivation layer, wherein the first passivation layer and the second passivation layer in which the reflective region is formed constitute Describe the reflective structure. 5. The method according to claim 4, characterized in that, before forming the reflective area, the method further comprises: A plurality of first metal interconnection lines respectively connected to the first doping region and the second doping region are formed in the first passivation layer, and in the plurality of first metal interconnection lines A plurality of first through holes filled with the first metal are formed below and penetrate the first passivation layer and the epitaxial layer. 6. The method according to claim 5, wherein the step of preparing the first bonding pad, the second bonding pad and the third bonding pad includes: A third passivation layer is deposited under the fourth doped region, and filling is formed in the third passivation layer at positions corresponding to the first doped region and the first through hole. There is a second through hole of the first metal, wherein the second through hole formed at a position corresponding to the first through hole is connected to the first through hole; forming a second metal interconnection line below the formed second through hole; depositing a fourth passivation layer under the third passivation layer in which the second metal interconnection line is formed, and etching the fourth passivation layer to expose the first metal interconnection line A part of the structure, wherein the second metal interconnection lines exposed at positions corresponding to the first doped region, the second doped region and the third doped region respectively form the third A bonding pad, the second bonding pad and the third bonding pad. 7. The method according to claim 6, characterized in that the method further comprises: Quenching elements connected to the first photosensitive element and the second photosensitive element respectively are prepared above the side of the epitaxial layer. 8. The method of claim 7, wherein the step of preparing the quenching element includes: Polysilicon is deposited on the side of the epitaxial layer over both edges of the first active area and the second active area or over the passive area on the outer surface of the epitaxial layer, and the The polysilicon is etched and doped to obtain the quenching element; A third through hole filled with the first metal is formed above the quenching element to connect with the first metal interconnection line. 9. The method according to any one of claims 1-8, characterized in that the method further includes: An isolation region is formed in the epitaxial layer on a side away from the substrate to separate the first doped region, the second doped region and the third doped region. 10. The method of claim 9, wherein the step of forming the isolation region includes: An inactive region on the outer surface of the epitaxial layer away from the first substrate is etched to form a trench. The inactive region is located between the first doped region and the first doped region. Between multiple active regions in the three-doped region; The trench is filled with oxide or nitride to form the isolation region. 11. The method according to any one of claims 1-8 and 10, characterized in that, before forming the first to third doped regions, the method further includes: A buried layer of the first conductivity type is formed in the first region and/or the second region. 12. The method according to any one of claims 1-8 and 10, characterized in that, before forming the first to third doped regions, the method further includes: A first well region, a second well region and/or a third well region respectively corresponding to the first doped region, the second doped region and/or the third doped region are formed in the epitaxial layer. well region. 13. The method according to any one of claims 1-8 and 10, characterized in that, before processing the first substrate, the method further includes: The reflective structure is bonded to the prepared second substrate. 14. The method according to any one of claims 1-8 and 10, characterized in that the method further includes: A convex lens is prepared below the fourth doped region at a position corresponding to the first photosensitive element and/or the second photosensitive element.