CN216624292U - Photodiode and photodiode detector - Google Patents

Abstract

The utility model provides a photodiode and a photodiode detector. The photodiode includes a first conductive type substrate, a photodiode, a reflective layer, and a second injection region. The first conductive type substrate is provided with a first surface and a second surface which are opposite; one side of the first surface of the first conductive type substrate is a light incident side; the first injection region is positioned in the first conduction type substrate and is exposed from the second surface of the first conduction type substrate; the material of the first injection region is a second conductive type material; the reflecting layer is positioned on one side of the first injection region, which is far away from the second surface of the first conductive type substrate; the second injection region is positioned in the first conductive type substrate and at the periphery of the first injection region, and the material of the second injection region is the first conductive type material. According to the structure, the reflecting layer is arranged on one side of the first injection region, which is away from the first surface of the first conductive type substrate, so that the absorption path of part of incident light is increased, and the generation efficiency of photon-generated carriers is improved.

Description

Photodiode and photodiode detector

Technical Field

The utility model belongs to the technical field of semiconductors, and particularly relates to a photodiode and a photodiode detector.

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.

SUMMERY OF THE UTILITY MODEL

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

a first conductivity type substrate having opposing first and second surfaces; the side where the first surface of the first conductive type substrate is located is a light incidence side;

a first implanted region in the first conductivity-type substrate and exposed from the second surface of the first conductivity-type substrate; the material of the first injection region is a second conductive type material;

the reflecting layer is positioned on one side of the first injection region, which is far away from the second surface of the first conductive type substrate;

a second implantation region located in the first conductive type substrate and at the periphery of the first implantation region; the material of the second injection region is the first conductive type material.

In some embodiments, the reflective layer is flat.

In some embodiments, the reflective layer is a curved structure protruding to a side facing away from the first conductive type substrate.

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

In some embodiments, the reflective layer has a size that corresponds to a size of the first implanted region.

In some embodiments, the reflective layer is a multi-layer dielectric reflective layer formed of high and low 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 first conductivity type substrate has a thickness in a range of 50 μm to 200 μm.

In some embodiments, the photodiode includes a first electrode line and a second electrode line disposed outside of the second surface of the first conductive-type substrate, the first electrode line being electrically connected to the first implantation region; the second electrode wire is electrically connected with the second injection region;

and a first electrode connected with the first electrode wire and a second electrode connected with the second electrode wire are arranged on the side surface of the first conductive type 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.

Based on the technical scheme, the reflecting layer is arranged on the side, away from the first surface of the first conductive type substrate, of the first injection region, so that the side, away from the first surface of the first conductive type substrate, of the first injection 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 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 an embodiment of the present invention;

fig. 3 is a cross-sectional view of a photodiode according to another embodiment of the present invention.

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 utility model.

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

The embodiment of the utility model provides a photodiode. The photodiode includes:

a first conductivity type substrate having opposing first and second surfaces; the side where the first surface of the first conductive type substrate is located is a light incidence side;

a first implanted region in the first conductivity-type substrate and exposed from a first surface of the first conductivity-type substrate;

the reflecting layer is positioned on one side of the first injection region, which is far away from the first surface of the first conductive type substrate;

and the second injection region is positioned in the first conductive type substrate and at the periphery of the first injection region, and the material of the second injection region is the first conductive type material.

According to the photodiode structure, the reflecting layer is arranged on the side, deviating from the first surface of the first conduction type substrate, of the first injection region, so that the side, deviating from the first surface of the first conduction type substrate, of the first injection region can be reflected back, the absorption path of part of incident light (particularly long-wave incident light) can be increased, and the generation efficiency of photon-generated carriers can be improved.

The photodiode provided in the present application is described in detail below with reference to fig. 1 to 3.

As shown in fig. 1 and fig. 2, a photodiode 100 of a photodiode according to an embodiment of the present invention has a passivation layer removed; fig. 2 is a cross-sectional view of the photodiode 100 shown in fig. 1. The photodiode 100 includes a first conductive type substrate 10, a first implantation region 20, a reflection layer 30, and a second implantation region 40. The first conductive type substrate 10 has a first surface 1001 and a second surface 1002 opposite to each other. The first implantation region 20 is located in the first conductive type substrate 10 and exposed from the second surface 1002 of the first conductive type substrate 10. The material of the first implanted region 20 is a second conductivity type material. The reflective layer 30 is located at a side of the first implanted region 20 facing away from the first conductive type substrate 10. The second implantation region 40 is located in the first conductive type substrate 10 and at the periphery of the first implantation region 20, and is spaced apart from the first implantation region 20. The material of the second implanted region 40 is a first conductivity type material.

Here, the side where the first surface 1001 of the first conductivity type 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 first conductivity type substrate 10, and the photodiode 100 is a back-illuminated photodiode. The first implant region 20 has a photosensitive material in the material, and the first implant region 20 forms a photosensitive region, so that a space charge region may be formed in the vicinity of the first implant 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 first conductive type substrate 10 is an N-type substrate, the second implantation region 40 is an N-type implantation region, and the first implantation region 20 is a P-type implantation region. The first and second implantation regions 20 and 40 may be formed by implanting N-type and P-type dopant materials, respectively. Wherein, the doping concentration of the N-type doping material of the second implantation region 40 is higher than that of the N-type doping material in the first conductive type substrate 10.

The second implantation region 40 may be a closed ring-shaped region located at the periphery of the first implantation region 20, but may also be an unclosed ring-shaped region. The dimension of the second implantation region 40 in the thickness direction of the first conductive type substrate 10 may be equal to the dimension of the first implantation region 20 in the thickness direction of the first conductive type substrate 10.

Further, the photodiode 100 includes a first electrode line 50 and a second electrode line 60 disposed outside the second surface 1002 of the first conductive type substrate 10, wherein the first electrode line 50 is electrically connected to the first implantation region 20, and the second electrode line 60 is electrically connected to the second implantation region 40. Portions of the first electrode lines 50 may be routed along near the edge of the first implant region 20 to electrically connect with the first implant region 20 from near the edge of the first implant region 20.

It should be noted that the second implantation region 40 may be exposed from the second surface 1002 of the first conductive type substrate 10 so as to be connected to the second electrode line 60.

Accordingly, the first conductive type substrate 10 is externally provided with a first electrode 81 and a second electrode 82 connected to the first electrode line 50 and the second electrode line 60, respectively, so as to be connected to an external power source or other structures. The first electrode 81 is disposed on the side of the second surface 1002 of the first conductive type substrate 10 and connected to the outer side of the first electrode line 50, and the second electrode 82 is disposed on the side of the second surface 1002 of the first conductive type substrate 10 and connected to the outer side of the second electrode line 60.

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 second surface 1002 of the first conductive type substrate 10 and the exposed surface of the first implantation region 20 from the first conductive type substrate 10 are provided with the dielectric layer 110. The dielectric layer 110 is a flat layer structure. Dielectric layer 110 is formed with a first recess through both upper and lower surfaces of dielectric layer 110 that exposes first implant region 20 and a second recess that exposes second implant region 40. A portion of the first electrode line 50 is disposed in the first groove, and another portion is disposed on a surface of the dielectric layer 110 facing away from the first conductive type substrate 10. A portion of second electrode line 60 is disposed in the second recess, and another portion is disposed on a surface of dielectric layer 110 on a side away from first conductivity-type substrate 10. The first electrode and the second electrode are disposed on a side of the dielectric layer 110 away from the first conductive type substrate 10. The reflective layer 30 is correspondingly disposed on a side of the dielectric layer 110 away from the first implantation region 20. In some embodiments, the reflective layer 30 is flat. The flat reflective layer 30 may be attached to a surface of the first implantation region 20 on a side close to the reflective layer 30.

In some embodiments, the reflective layer 30 has a size that corresponds to the size of the first implanted region 20. For example, the shape and size of the reflective layer 30 may be the same or substantially the same as the shape and size of the first implanted region 20.

In some embodiments, the reflective layer 30 is a multi-layer dielectric reflective layer formed of high and low index materials of different optical thicknesses. For example, the reflective 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 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.

Further, in some embodiments, the side of the first conductive type substrate 10 where the first surface 1001 is located is provided with an anti-reflection layer 70. The anti-reflection layer 70 covers at least the surface of the first implantation region 20. Of course, the remaining first surface 1001 of the first conductivity type substrate 10 may be covered. Antireflection layer 70 may be an antireflection layer structure formed by a plurality of antireflection films having different optical thicknesses, and the thicknesses of the antireflection films may be set according to specific situations, which is not limited in this application.

Further, the side of the first conductive type substrate 10 where the second surface 1002 is located is provided with a passivation layer 90. The passivation layer 90 covers at least the surfaces of the first electrode lines 50, the second electrode lines 60, and the reflective layer 30. Of course, the passivation layer may also cover the remaining second surface 1002 of the first conductive type substrate 10.

It should be noted that, in some embodiments, the photodiode may also be directly mounted without providing the first electrode line and the second electrode line.

As shown in fig. 3, fig. 3 is a cross-sectional view of a photodiode 200 according to another embodiment of the present invention. For ease of understanding, the same reference numerals are used for the same or similar structures of the photodiode 200 shown in fig. 3 as those of the photodiode 100 shown in fig. 1 and 2 described above.

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

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

Of course, the reflective layer 30' may also be provided to be partially bent to the side away from the first conductive-type substrate 10. In addition, the reflective layer 30 has a reflective surface facing the first injection region 20, and the reflective layer 30 may be partially or entirely concave-curved, and the reflective layer having a side facing away from the first injection region 20 is not particularly limited.

In some embodiments, for the dielectric layer 110 'to be disposed, 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 first implantation region 20. A reflective layer 30' is particularly provided on the surface of the raised structure on the side facing away from the first implanted region 20. Accordingly, the passivation layer 90 'forms corresponding recess regions at the protruding structures and the reflective 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 first conductive type substrate is a P-type substrate, the second injection region is a P-type injection region, and the first injection region is an N-type injection region. The first electrode is correspondingly a cathode and the second electrode is an anode.

The present application further provides a photodiode detector. The photodiode detector comprises a plurality of photodiodes 100 or 200, and the photodiodes 100 or 200 are arranged in an array.

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 (10)

1. A photodiode, comprising:

a first conductivity type substrate having opposing first and second surfaces; the side where the first surface of the first conductive type substrate is located is a light incidence side;

a first implanted region in the first conductivity-type substrate and exposed from the second surface of the first conductivity-type substrate; the material of the first injection region is a second conductive type material;

the reflecting layer is positioned on one side of the first injection region, which is deviated from the second surface of the first conductive type substrate;

a second implantation region located in the first conductive type substrate and at the periphery of the first implantation region; the material of the second injection region is the first conductive type material.

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

3. The photodiode of claim 1, wherein at least a portion of the reflective layer is a meander-like structure protruding to a side facing away from the first conductivity type substrate.

4. The photodiode of claim 3, wherein the reflective layer is arcuately curved or spherically coronally curved.

5. The photodiode of claim 1, wherein a size of the reflective layer is identical to a size of the first implanted region.

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

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

8. The photodiode of claim 1, wherein the first conductivity type substrate has a thickness in a range of 50 μ ι η to 200 μ ι η.

9. The photodiode of claim 1, wherein the photodiode comprises first and second electrode lines disposed outside of the second surface of the first conductivity-type substrate, the first electrode lines being electrically connected to the first implant region; the second electrode wire is electrically connected with the second injection region;

and a first electrode connected with the first electrode wire and a second electrode connected with the second electrode wire are arranged on the side surface of the first conductive type substrate.

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

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