CN114300495A

CN114300495A - Photodiode, photoelectric detector and manufacturing method thereof

Info

Publication number: CN114300495A
Application number: CN202111643551.6A
Authority: CN
Inventors: 祁春超; 樊堃; 仇筱乐
Original assignee: Hangzhou Hikvision Digital Technology Co Ltd
Current assignee: Hangzhou Hikvision Digital Technology Co Ltd
Priority date: 2021-12-29
Filing date: 2021-12-29
Publication date: 2022-04-08

Abstract

The invention provides a photodiode, a photodetector and a method for manufacturing the same. The photodiode comprises a substrate, a first doping area, a second doping area, a dielectric layer and a reflecting layer, wherein the substrate is provided with a first surface and a second surface which are mutually deviated, and the substrate is made of a first conductive type material; the first doped region is arranged in the substrate and exposed out of the second surface of the substrate, and the first doped region is made of a first conductive type material; the second doped region is arranged in the substrate and exposed from the second surface of the substrate, and the material of the second doped region is a second conductive type material; the dielectric layer is positioned on the exposed surface of the second doped region from the substrate; the reflecting layer is correspondingly arranged on the surface of the dielectric layer deviating from the second doped region. According to the structure, the reflecting layer is arranged on the surface of the dielectric layer, which deviates from the second doping area, so that light emitted from the second doping area can be reflected back, the absorption path of part of incident light can be increased, and the generation efficiency of photon-generated carriers can be improved.

Description

Photodiode, photoelectric detector and manufacturing method thereof

Technical Field

The invention belongs to the technical field of semiconductors, and particularly relates to a photodiode, a photoelectric detector and a manufacturing method thereof.

Background

Compared with the traditional front-illuminated photodiode detector, the back-illuminated photodiode has the advantages of high mounting reliability, small pixel pitch, easiness in splicing, small crosstalk, good consistency and the like in the application of an array module; since the space charge region of the back-illuminated photodiode is located at the inner side near the front surface, the substrate needs to be thinned to ensure light entering from the back surface. In this way, the absorption path of the incident light in the substrate is easily reduced, and particularly, the absorption efficiency of the long wave is reduced, so that the photo-generated carriers generated in the space charge region are reduced, thereby causing a reduction in the optical responsivity of the semiconductor device having the back-illuminated photodiode.

Disclosure of Invention

According to a first aspect of embodiments of the present invention, there is provided a photodiode comprising:

the substrate is provided with a first surface and a second surface which are mutually deviated, and the material of the substrate is a first conductive type material;

the first doping area is arranged in the substrate and exposed out of the second surface of the substrate, and the first doping area is made of a first conductive type material;

the second doping area is arranged in the substrate and is exposed from the second surface of the substrate;

the dielectric layer is positioned on the surface of the second doped region exposed from the substrate;

and the reflecting layer is correspondingly arranged on the surface of the dielectric layer deviating from the second doped region.

In some embodiments, the light-reflective layer is flat.

In some embodiments, at least a portion of the light-reflective layer is a curved structure that protrudes to a side facing away from the second surface of the substrate.

In some embodiments, the light-reflective layer is arcuately curved or spherically crowned.

In some embodiments, the size of the light reflecting layer is identical to the size of the second doped region.

In some embodiments, the light-reflecting layer is a multi-layer dielectric light-reflecting layer formed of high and low refractive index materials of different optical thicknesses.

In some embodiments, the high refractive index material is HfO2 and the low refractive index material is SiO 2.

In some embodiments, the photodiode comprises a first electrode line, a second electrode line, a first electrode, and a second electrode; the first electrode wire is arranged on one side, away from the substrate, of the second doping region and is electrically connected with the second doping region; the second electrode wire is arranged on one side of the first doping region, which is far away from the substrate, and is electrically connected with the first doping region; the first electrode is arranged on one side of the second surface of the substrate and connected to the outer side of the first electrode wire, and the second electrode is arranged on one side of the second surface of the substrate and connected to the outer side of the second electrode wire.

In some embodiments, the dielectric layer is located on the surface of the first doped region exposed from the substrate, the surface of the second doped region exposed from the substrate, and the second surface of the substrate, and the first electrode and the second electrode are both located on the surface of the dielectric layer facing away from the substrate.

According to a second aspect of embodiments of the present invention, there is provided a photodiode detector comprising a plurality of photodiodes as described above, the plurality of photodiodes being arranged in an array.

According to a third aspect of embodiments of the present invention, there is provided a method of manufacturing a photodetector, including:

providing a substrate, wherein the substrate is provided with a first surface and a second surface which are opposite to each other, and the material of the substrate is a first conductive type material;

injecting a first type doping material into a first preset area on the second surface of the substrate to form a first doping area, wherein the first doping area is exposed from the second surface of the substrate; the material of the first doped region is a first conductive type material;

injecting a second type doping material into a second preset area on the second surface of the substrate to form a second doping area, wherein the second doping area is exposed out of the second surface of the substrate, and the second doping area is made of a second conductive type material;

forming a dielectric layer, wherein the dielectric layer is positioned on the surface of the second doping area exposed from the substrate;

and forming a reflecting layer correspondingly arranged on the surface of the dielectric layer deviating from the second doped region.

In some embodiments, the light-reflecting layer is flat or at least part of the light-reflecting layer is a curved structure protruding to the side of the second surface facing away from the substrate.

In some embodiments, after forming the light reflecting layer, the method comprises:

forming a first electrode wire, a second electrode wire, a first electrode and a second electrode; the first electrode wire is arranged on one side, away from the substrate, of the second doping region and is electrically connected with the second doping region; the second electrode wire is arranged on one side of the first doping region, which is far away from the substrate, and is electrically connected with the first doping region; the first electrode is arranged on one side of the second surface of the substrate and connected to the outer side of the first electrode wire, and the second electrode is arranged on one side of the second surface of the substrate and connected to the outer side of the second electrode wire.

In some embodiments, the dielectric layer is located on a surface of the first doped region exposed from the substrate, a surface of the second doped region exposed from the substrate, and a second surface of the substrate, and the forming the first electrode line, the second electrode line, the first electrode, and the second electrode includes:

forming a first groove exposing the second doping region and a second groove exposing the first doping region in the dielectric layer;

forming a metal layer on the surfaces of the first groove, the second groove and the insulating layer, which are deviated from the substrate;

and etching the metal layer to form the first electrode wire, the second electrode wire, the first electrode and the second electrode.

In some embodiments, the forming the light reflecting layer comprises:

forming a reflecting material layer on one side of the dielectric layer, which is far away from the substrate;

and etching the reflecting material layer to form the reflecting layer.

In some embodiments, at least a portion of the light-reflecting layer is a curved structure protruding toward a side away from the second surface of the substrate, and the forming the dielectric layer includes:

forming a dielectric layer on the surface of the first doped region exposed from the substrate, the surface of the second doped region exposed from the substrate and the second surface of the substrate, wherein a protruding structure corresponding to the second doped region is formed on one side of the dielectric layer, which is far away from the substrate;

the forming of the light reflecting layer includes: and forming a light reflecting layer on the surface of the raised structure.

Based on the technical scheme, the light reflecting layer is arranged on the side, away from the first surface of the substrate, of the second doping region, so that the side, away from the first surface of the substrate, of the second doping region is favorably reflected back, the absorption path of part of incident light (particularly long-wave incident light) is favorably increased, and the generation efficiency of a photon-generated carrier is favorably improved.

Drawings

Fig. 1(a) is a cross-sectional view of a photodiode according to an embodiment of the present invention;

fig. 1(b) is a schematic diagram of a photodiode according to an embodiment of the present invention with a passivation layer removed;

FIG. 2 is a cross-sectional view of a photodiode according to another embodiment of the present invention;

FIG. 3 is a flow chart of a method for fabricating a photodetector according to an embodiment of the present invention;

fig. 4 to 11 are manufacturing process diagrams of the photodetector having the photodiode shown in fig. 1(a) and 1 (b);

fig. 12 to 16 are partial manufacturing process diagrams of the photodetector having the photodiode shown in fig. 2.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

Embodiments of the present invention are described in detail below with reference to the accompanying drawings.

An embodiment of the present invention provides a photodiode, including:

According to the structure, the reflecting layer is arranged on the side, away from the first surface of the substrate, of the second doping region, so that the side, away from the first surface of the substrate, of the second doping region is favorably reflected back, the absorption path of part of incident light (particularly long-wave incident light) is favorably increased, and the generation efficiency of photon-generated carriers is favorably improved.

The photodiode and the method for manufacturing the same provided by the present application are described in detail below with reference to fig. 1(a) to 16.

As shown in fig. 1(a), fig. 1(a) is a cross-sectional view of a photodiode 100 according to an embodiment of the present invention. The photodiode 100 includes a substrate 10, a second doped region 20, a light reflecting layer 30, a first doped region 40, and a dielectric layer 110. The substrate 10 has a first surface 1001 and a second surface 1002 facing away from each other. The first doped region 40 is disposed in the substrate 10 and exposed at the second surface 1002 of the substrate 10, and the material of the first doped region 40 is a first conductive type material. The second doped region 20 is disposed in the substrate 10 and exposed from the second surface 1002 of the substrate 10. A dielectric layer 110 is located on the surface of the second doped region 20 exposed from the substrate 10. The light reflecting layer 30 is correspondingly disposed on the surface of the dielectric layer 110 away from the second doped region 20.

Here, the side where the first surface 1001 of the substrate 10 is located is a light incident side, incident light may be incident into the photodiode 100 from the first surface 1001 of the substrate 10, and the photodiode 100 is a back-illuminated photodiode. The material of the second doped region 20 has a photosensitive material therein, and the second doped region 20 forms a photosensitive region, so that a space charge region can be formed in the vicinity of the second doped region 20.

Here, the first conductivity type is N-type, and the second conductivity type is P-type. The first conductive type material is an N-type material, and the second conductive type material is a P-type material. Accordingly, the substrate 10 is an N-type substrate. The first doped region 40 is an N-type doped region and the second doped region 20 is a P-type doped region. The first doped region 40 and the second doped region 20 can be formed by implanting N-type and P-type doping materials, respectively. Wherein, the doping concentration of the N-type doping material of the first doping region 40 is higher than that of the N-type doping material in the substrate 10.

Here, the first doping region 40 may be located at the periphery of the second doping region 20. For example, the first doping region 40 may be a closed ring-shaped region located at the periphery of the second doping region 20, but may also be an unclosed ring-shaped region. A dimension of the first doped region 40 in a thickness direction of the substrate 10 may be greater than a dimension of the second doped region 20 in the thickness direction of the substrate 10.

Dielectric layer 110 may be a dielectric layer disposed on second surface 1002 of substrate 10, the exposed surface of second doped region 20 from substrate 10, and the exposed surface of first doped region 40 from substrate 10.

Further, as shown in fig. 1(b), the photodiode 100 includes a first electrode line 50 and a second electrode line 60. The first electrode lines 50 are disposed on a side of the second doped region 20 away from the substrate 10 and electrically connected to the second doped region 20. The second electrode lines 60 are disposed on a side of the first doped region 40 facing away from the substrate 10 and electrically connected to the first doped region 40. Portions of the first electrode lines 50 may be routed along near the edge of the second doped region 20 to electrically connect with the second doped region 20 from near the edge of the second doped region 20.

Further, as shown in fig. 1(b), the photodiode 100 further includes a first electrode 81 and a second electrode 82 for connecting with an external power source or other external structures. The first electrode 81 is disposed on the second surface 1002 of the substrate 10 and connected to the outer side of the first electrode line 50, and the second electrode 82 is disposed on the second surface 1002 of the substrate 10 and connected to the outer side of the second electrode line 60. For the dielectric layer 110 disposed on the second surface 1002 of the substrate 10, the surface of the second doped region 20 exposed from the substrate 10, and the surface of the first doped region 40 exposed from the substrate 10, both the first electrode 81 and the second electrode 82 may be disposed on the surface of the dielectric layer 110 facing away from the substrate 10 or may partially penetrate through the dielectric layer 110, and the other portion is disposed on the surface of the dielectric layer 110 facing away from the substrate 10.

Here, the first electrode line 50 is an anode conductive line, and the first electrode 81 is an anode. Here, the second electrode line 60 is a cathode conductive line, and the second electrode 82 is a cathode.

In some embodiments, the light-reflective layer 30 is flat. The flat reflective layer 30 may be disposed on a surface of the dielectric layer 110 adjacent to the side of the reflective layer 30.

In some embodiments, the size of the light reflecting layer 30 is identical to the size of the second doped region 20. For example, the shape and size of the light reflecting layer 30 may be the same as or substantially the same as those of the second doped region 20.

In some embodiments, the light reflecting layer 30 is a multi-layer dielectric light reflecting layer formed of high and low refractive index materials of different optical thicknesses. For example, the light reflecting layer 30 may include a high refractive index layer and a low refractive index layer stacked together with the high refractive index layer. The high refractive index layer is formed of a high refractive index material, and the low refractive index layer is formed of a low refractive index material.

In some embodiments, the high refractive index material is HfO2 and the low refractive index material is SiO 2. Of course, in other embodiments, the high refractive index material and the low refractive index material may be other materials, which is not limited in this application and may be set according to specific situations.

In other embodiments, the light-reflective layer may also be a single layer dielectric structure. For example, tungsten metal or a new material having a high reflectance may be used.

In some embodiments, the thickness of the first conductive type substrate 10 ranges from 50 μm to 200 μm.

It should be noted that, for the light reflecting layer 30 having a metal or other conductive material, a dielectric layer may be used as an insulating material layer between the second doped region 20 and the light reflecting layer 30. In addition, in some embodiments, an insulating film layer may be further formed on the surface of the second doped region 20 during the fabrication of the second doped region 20, and the insulating film layer may also be used as an insulating material layer between the second doped region 20 and the light-reflecting layer 30.

Further, in some embodiments, the side of the substrate 10 on which the first surface 1001 is located is provided with an anti-reflection layer 70. The anti-reflection layer 70 covers at least the area of the first surface 1001 of the substrate 10 opposite to the second doped region 20, but may cover the entire area of the first surface 1001 of the substrate 10. The antireflection layer 70 may be an antireflection layer structure formed by multiple antireflection films with different optical thicknesses, and the thickness of each antireflection film may be set according to specific situations, which is not limited in this application.

Further, the side of the substrate 10 where the second surface 1002 is located is provided with a passivation layer 90. The passivation layer 90 at least covers the first electrode lines 61, the second electrode lines 60, the surface of the light reflecting layer 30 away from the second doped region 20 and away from the dielectric layer 110, and the surface of the dielectric layer 110 on the side away from the substrate 10.

As shown in fig. 2, the present application further provides a photodiode 200. For ease of understanding, the photodiode 200 shown in fig. 2 has the same structure as the photodiode 100 shown in fig. 1(a) described above, and the same reference numerals are used.

Different from the photodiode 100, the light reflecting layer 30 'of the photodiode 200 is curved, and the light reflecting layer 30' is specifically a curved structure protruding to the side away from the first surface 1001 of the substrate 10, so as to better reflect and converge incident light and further improve the generation efficiency of photo-generated carriers.

It should be noted that, the whole light reflecting layer 30' may be curved, such as bow-shaped curve, spherical crown-shaped curve, etc., so that the whole light reflecting layer has a certain curvature to better reflect and converge the incident light.

Of course, the light-reflecting layer 30' may also be arranged to be partially curved to the side of the first surface 1001 facing away from the substrate 10. In addition, the light reflecting layer 30 'has a reflecting surface facing the second doped region 20, and the light reflecting layer 30' may be partially or entirely concave-curved, and the side of the light reflecting layer facing away from the second doped region 20 is not particularly limited.

A side of the dielectric layer 110' facing away from the first conductive type substrate 10 is formed with a protruding structure corresponding to the second doped region 20. The light-reflecting layer 30' is particularly provided on the surface of the raised structure on the side facing away from the second doped region 20. Accordingly, the passivation layer 90 'forms corresponding recess regions at the protruding structures and the light reflection layer 30'.

As shown in fig. 3, the present application further provides a photodiode detector, where the photodiode detector includes a plurality of

photodiodes

100 or 200 as described above, and the

photodiodes

100 or 200 are arranged in an array.

The present application further provides a method for manufacturing a photodetector. As shown in fig. 2, the method of manufacturing the photodetector includes steps S101 to S109 as follows:

in step S101, providing a substrate having a first surface and a second surface facing away from each other, wherein the substrate is made of a first conductive type material;

in step S103, a first type doping material is implanted into a first predetermined region of the second surface of the substrate to form a first doping region, and the first doping region is exposed from the second surface of the substrate; the material of the first doped region is a first conductive type material;

in step S105, a second type doping material is implanted into a second predetermined region on the second surface of the substrate to form a second doping region, the second doping region is exposed from the second surface of the substrate, and the second doping region is made of a second conductive type material;

in step S107, a dielectric layer is formed, where the dielectric layer is located on the exposed surface of the second doped region from the substrate;

in step S109, a light-reflecting layer is formed and correspondingly disposed on the surface of the dielectric layer away from the second doped region.

The following describes the manufacturing method of the photodetector in detail with reference to fig. 4 to 11.

As shown in fig. 4, in step S101, a substrate 10 is provided, the substrate 10 having a first surface 1001 and a second surface 1002 facing away from each other, the material of the substrate 10 being a first conductive type material.

As shown in fig. 5, in step S103, a first type doping material is implanted into a first predetermined region of the second surface 1002 of the substrate 10 to form a first doping region 40, and the first doping region 40 is exposed from the second surface 1002 of the substrate 10. The first doping region 40 has a doping concentration higher than that of the substrate 10.

As shown in fig. 6, in step S105, a second type doping material is implanted into a second predetermined region of the second surface 1002 of the substrate 10 to form a second doping region 20. The second doped region 20 is exposed from the second surface 1002 of the substrate 10, and the material of the second doped region 20 is a second conductive type material.

Here, the first conductivity type is N-type, and the second conductivity type is P-type. The first conductive type material is an N-type material, and the second conductive type material is a P-type material. Accordingly, the substrate 10 is an N-type substrate. The first doped region 40 is an N-type doped region and the second doped region 20 is a P-type doped region. The first doping region 40 has a doping concentration of the N-type doping material higher than that of the substrate 10. The first type doped material is N type doped material, and the second type doped material is P type doped material.

As shown in fig. 7, in step S107, a dielectric layer 110 is formed. The dielectric layer 110 is a layer of insulating material disposed on the second surface 1002 of the substrate 10, the exposed surface of the second doped region 20 from the substrate 10, and the exposed surface of the first doped region 40 from the substrate 10.

The dielectric layer 110 may be silicon dioxide or other insulating material. The metal layer can be formed by chemical vapor deposition.

In some other embodiments, the dielectric layer may also be an insulating film layer formed on the surface of the second doped region when the second doped region is fabricated. As long as the dielectric layer is ensured on the surface of the second doped region 20 exposed from the substrate 10 to facilitate the subsequent disposition of the light-reflecting layer.

Dielectric layer 110 here is a flat layer structure.

As shown in fig. 8, in step S109, a light reflecting layer 30 is formed on a side of the dielectric layer 110 away from the second doped region 20. The light reflecting layer 30 is disposed corresponding to the second doped region 20.

The light-reflecting layer 30 is flat.

In some embodiments, the size of the light reflecting layer 30 is identical to the size of the second doped region 20.

In some embodiments, this step S109 may be implemented by the following steps S1091 and S1092:

in step S1091, a reflective material layer is formed on the side of dielectric layer 110 facing away from substrate 10.

The layer of reflective material covers the entire surface of dielectric layer 110 on the side facing away from substrate 10. May be formed by means of vapor deposition. For embodiments in which the light-emitting layer 30 is a multi-layer medium formed by alternating high and low refractive index materials of different optical thicknesses, each may be formed by means of a corresponding vapor deposition.

In step S1092, the reflective material layer is etched to form the reflective layer 30.

And etching away the part of the reflecting material layer outside the region corresponding to the light reflecting layer 30, thereby forming the light reflecting layer 30.

In other embodiments, of course, a protective layer may be disposed on the surface of the dielectric layer except the area corresponding to the reflective layer, and the protective layer may expose the area corresponding to the reflective layer, and then a material for forming the reflective material layer is deposited in the area corresponding to the reflective layer, so as to form the reflective layer, and then the protective layer is removed.

After step S109, the method comprises the following step S110:

in step S110, a first electrode line 50, a second electrode line 60, a first electrode and a second electrode are formed. The first electrode lines 50 are disposed on a side of the second doped region 20 away from the substrate 10 and electrically connected to the second doped region 20. Portions of the first electrode lines 50 may be routed along near the edge of the second doped region 20 to electrically connect with the second doped region 20 from near the edge of the second doped region 20. The second electrode line 60 is disposed on a side of the first doped region 40 away from the substrate 10 and electrically connected to the first doped region 40. The first electrode is disposed on the second surface 1002 of the substrate 10 and connected to the outer side of the first electrode line 50. The second electrode is disposed on the side of the second surface 1002 of the substrate 10 and connected to the outer side of the second electrode line 60.

The above step S110 can be realized by the following steps S1101 to S1103:

in step S1101, a first groove exposing the second doped region 20 and a second groove exposing the first doped region are formed in the dielectric layer 110.

The first groove and the second groove may be formed by laser drilling, or may be formed by other drilling methods, which is not limited in this application.

In step S1102, a metal layer is formed on the surfaces of the first recess, the second recess and the dielectric layer 110 away from the substrate 10.

In step S1103, the metal layer is etched to form a first electrode line 50, a second electrode line 60, a first electrode, and a second electrode.

After step S110, the method further comprises the following step S120:

a passivation layer 90 is formed on the side of the substrate 10 where the second surface 1002 is located. The passivation layer 90 at least covers the first electrode line 61, the second electrode line 60, the surface of the light reflecting layer 30 away from the second doped region 20 and away from the dielectric layer 110, and the surface of the dielectric layer 110 on the side away from the substrate 10.

The first and second electrodes are exposed from the passivation layer 90 to be electrically connected to other external structures.

After step S120, the method further comprises the following step S130:

in step S130, an antireflection layer 70 is formed on the first surface 1001 of the substrate 10.

The side of the substrate 10 on which the first surface 1001 is located is provided with an anti-reflection layer 70. The anti-reflection layer 70 covers at least the area of the first surface 1001 of the substrate 10 opposite to the second doped region 20, but may cover the entire area of the first surface 1001 of the substrate 10. The antireflection layer 70 may be an antireflection layer structure formed by multiple antireflection films with different optical thicknesses, and the thickness of each antireflection film may be set according to specific situations, which is not limited in this application.

A method of manufacturing the photodetector will be described with reference to fig. 12 to 16. The steps in the manufacturing method of the photodetector are substantially the same as those in the manufacturing method of the photodetector described above, and the steps before the dielectric layer 110' is provided are the same as those in the manufacturing method of the photodetector described above, and reference may be made to the above-mentioned description. The following description mainly deals with differences.

In step S107, a dielectric layer 110' is formed, as shown in fig. 12.

The side of the dielectric layer 110' facing away from the substrate 10 is formed with a raised structure 111 corresponding to the second doped region 20. The protruding structure can be arranged according to the shape of the light reflecting layer.

The dielectric layer 110 is a layer of insulating material disposed on the second surface 1002 of the substrate 10, the exposed surface of the second doped region 20 from the substrate 10, and the exposed surface of the first doped region 40 from the substrate 10.

In specific implementation, an insulating material layer with a larger thickness may be formed first, and then the insulating material layer is etched to form the dielectric layer 110' with a raised structure.

In some other embodiments, the dielectric layer may also be an insulating film layer formed on the surface of the second doped region when the second doped region is fabricated. It is sufficient to ensure that the dielectric layer is located on the surface of the second doped region 20 exposed from the substrate 10, and the outer surface thereof is formed with corresponding protrusions to facilitate the subsequent arrangement of the light-reflecting layer.

In step S109, a light reflecting layer 30' is formed on the surface of the protruding structure.

At least part of the light-reflecting layer 30' is a meander-like structure protruding to the side facing away from the substrate 10. The specific structure of the reflective layer 30' can be found in the above description related to the embodiment shown in fig. 2, and will not be described herein again.

Further, the passivation layer 90 'formed in the subsequent step forms corresponding recess regions at the protrusion structures and the light reflection layer 30'.

It should be noted that, in some other embodiments, the first conductivity type may also be P-type, and the second conductivity type may be N-type. Correspondingly, the substrate is a P-type substrate, the first doped region is a P-type doped region, and the second doped region is an N-type doped region. The first electrode is correspondingly a cathode and the second electrode is an anode.

Those skilled in the art will appreciate that the drawings are merely schematic representations of one preferred embodiment and that the blocks or flow diagrams in the drawings are not necessarily required to practice the present invention. The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and the present invention shall be covered thereby. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims

1. A photodiode, comprising:

the first doping area is arranged in the substrate and exposed from the second surface of the substrate, and the material of the first doping area is a first conductive type material;

the second doping area is arranged in the substrate and exposed from the second surface of the substrate, and the material of the second doping area is a second conductive type material;

2. The photodiode of claim 1, wherein the light reflecting layer is flat.

3. The photodiode of claim 1, wherein at least a portion of the light-reflecting layer is a curved structure that protrudes toward a side of the second surface facing away from the substrate.

4. The photodiode of claim 3, wherein the light reflecting layer is arcuately curved or spherically crowned.

5. The photodiode of claim 1, wherein the light reflecting layer has a size corresponding to a size of the second doped region.

6. The photodiode of claim 1, wherein the light reflecting layer is a multi-layer dielectric light reflecting layer formed of high refractive index material and low refractive index material of different optical thicknesses.

7. The photodiode of claim 6, wherein the high index material is HfO₂The low refractive index material is SiO₂。

8. The photodiode of claim 1, wherein the photodiode comprises a first electrode line, a second electrode line, a first electrode, and a second electrode; the first electrode wire is arranged on one side, away from the substrate, of the second doping region and is electrically connected with the second doping region; the second electrode wire is arranged on one side of the first doping region, which is far away from the substrate, and is electrically connected with the first doping region; the first electrode is arranged on one side of the second surface of the substrate and connected to the outer side of the first electrode wire, and the second electrode is arranged on one side of the second surface of the substrate and connected to the outer side of the second electrode wire.

9. The photodiode of claim 8, wherein the dielectric layer is located on a surface of the first doped region exposed from the substrate, a surface of the second doped region exposed from the substrate, and a second surface of the substrate, and wherein the first and second electrodes are both located on a surface of the dielectric layer facing away from the substrate.

10. A photodiode detector, comprising a plurality of photodiodes according to any one of claims 1 to 9 arranged in an array.

11. A method of fabricating a photodetector, comprising:

12. The method of claim 11, wherein the light-reflecting layer is flat or at least a portion of the light-reflecting layer is a curved structure that projects away from the second surface of the substrate.

13. The method of manufacturing a photodetector of claim 11, wherein after forming the light reflecting layer, the method comprises:

14. The method of claim 13, wherein the dielectric layer is disposed on a surface of the first doped region exposed from the substrate, a surface of the second doped region exposed from the substrate, and a second surface of the substrate, and wherein forming the first electrode line, the second electrode line, the first electrode, and the second electrode comprises:

forming a metal layer on the surfaces of the first groove, the second groove and the dielectric layer, which are deviated from the substrate;

15. The method of manufacturing a photodetector of claim 14, wherein the forming of the light reflecting layer comprises:

and etching the reflecting material layer to form the reflecting layer.

16. The method of manufacturing a photodetector of claim 14, wherein at least a portion of the light reflecting layer is a curved structure protruding toward a side facing away from the second surface of the substrate, and the forming the dielectric layer comprises: