CN118867029A - Single photon avalanche diode and its manufacturing method and photodetector - Google Patents

Abstract

The present invention discloses a single-photon avalanche diode, a manufacturing method thereof, and a photoelectric detector. An isolation region is set to divide a first doping region, a second doping region, a third doping region, and a fourth doping region into electrically isolated preset equal parts, and a hierarchical structure of the first doping region, the second doping region, the third doping region, and the fourth doping region is set. Edge breakdown is used to improve detection efficiency, and a SPAD that relies on edge breakdown to work is obtained. Without reducing the overall size of the SPAD, the imaging resolution of the SPAD array chip is improved and the detection efficiency is guaranteed.

Description

Single photon avalanche diode and its manufacturing method and photodetector

Technical Field

The present invention relates to the field of photoelectric detection technology, and in particular to a single-photon avalanche diode and a manufacturing method thereof, and a photoelectric detector.

Background Art

Single-photon avalanche diode (SPAD) is an important optoelectronic device that can detect single photons. SPAD devices with different structures are constantly being born, and their performance is constantly improving. The working principle of SPAD is to apply a reverse bias greater than the breakdown voltage (BV) to it, so that it is in Geiger mode. When a single photon is incident, photogenerated carriers will be generated to trigger an avalanche, and SPAD will obtain extremely high current gain, thereby realizing sensitive detection of single photons. For SPAD array chips, if you want to improve the image resolution on the same chip size, you need to reduce the device size. However, when the device size is reduced to below 10um, higher requirements are placed on the design and manufacturing process of the device.

Summary of the invention

The main purpose of the present invention is to provide a single-photon avalanche diode and a manufacturing method thereof and a single-photon avalanche detector, and to design a SPAD device with position resolution capability, which can be used as multiple sub-SPADs to improve the imaging resolution of the SPAD array chip without reducing the overall size of the SPAD.

To achieve the above object, the present invention provides a single photon avalanche diode, comprising:

A substrate of a first doping type, wherein an active region is electrically isolated by a first isolation region in the substrate;

The active region is provided with a first doping region and a second doping region of a second doping type, and is further provided with a third doping region and a fourth doping region of the first doping type, the first doping type is opposite to the second doping type, the doping concentration of the first doping region is higher than that of the second doping region, the doping concentration of the fourth doping region is higher than that of the third doping region and the substrate, the doping concentration of the third doping region gradually increases in a direction away from the upper surface of the active region, and the first doping region and the fourth doping region are used as an anode contact region and a cathode contact region respectively according to the doping type;

The third doping region extends from the upper surface of the active region to the inside of the active region, the second doping region extends from the upper surface of the third doping region to the inside of the third doping region, and is surrounded by the third doping region whose width and depth are both greater than the second doping region, the first doping region extends from the upper surface of the second doping region to the inside of the second doping region, and is surrounded by the second doping region whose width and depth are both greater than the first doping region, the fourth doping region extends from the upper surface of the active region to the inside of the active region along the entire edge of the first isolation region, and a side of the fourth doping region facing away from the first isolation region is connected to a side of the third doping region close to the first isolation region;

A second isolation region is also provided in the substrate, and the second isolation region divides the first doped region, the second doped region, the third doped region and the fourth doped region into preset equal parts which are electrically isolated from each other, so that the active region is divided into sub-regions of the preset equal parts, and the structure in each sub-region constitutes a sub-single-photon avalanche diode.

Optionally, the depth of the fourth doping region is less than the depth of the third doping region, and a fifth doping region of the first doping type is also provided in the active region, the doping concentration of the fifth doping region is less than the doping concentration of the fourth doping region, the fifth doping region extends along the entire edge of the first isolation region, from the upper surface of the fourth doping region to the lower surface of the active region, the side of the fifth doping region facing away from the first isolation region is connected to the third doping region, and the depth of the fifth doping region is greater than the depth of the third doping region.

Optionally, the first isolation region and the second isolation region are isolation regions formed by deep trench isolation.

Optionally, the orthographic projection of the active area on the upper surface of the substrate is a rectangle, and the orthographic projection of the second isolation area on the upper surface of the substrate is a cross, so as to divide the first doped area, the second doped area, the third doped area and the fourth doped area into four equal parts that are electrically isolated from each other.

Optionally, the first doping type is p-type doping, and the second doping type is n-type doping.

In addition, to achieve the above objectives, the present invention also provides a method for manufacturing a single-photon avalanche diode, which is used to manufacture the single-photon avalanche diode as described above, comprising:

Providing the substrate, and defining the active area on the substrate;

Performing ion implantation in the active region to form a first ion implantation region, a second ion implantation region, a third ion implantation region and a fourth ion implantation region on the substrate, wherein the first ion implantation region extends from the upper surface of the active region to the interior of the active region, the second ion implantation region extends from the upper surface of the third ion implantation region to the interior of the third ion implantation region and is surrounded by the third ion implantation region having a width and a depth greater than that of the second ion implantation region, the first ion implantation region extends from the upper surface of the second ion implantation region to the interior of the second ion implantation region and is surrounded by the second ion implantation region having a width and a depth greater than that of the first ion implantation region, the fourth ion implantation region extends from the upper surface of the active region to the interior of the active region along the entire edge of a side of the third ion implantation region away from the second ion implantation region, and the side of the fourth ion implantation region away from the third ion implantation region reaches the edge of the active region;

The first isolation region is fabricated on the substrate along the outer edge of the active region, and the second isolation region is fabricated on the substrate, wherein the second isolation region electrically isolates the first ion implantation region, the second ion implantation region, the third ion implantation region and the fourth ion implantation region into preset equal parts, and the first ion implantation region, the second ion implantation region, the third ion implantation region and the fourth ion implantation region isolated by the second isolation region serve as the first doping region, the second doping region, the third doping region and the fourth doping region, respectively.

Optionally, the step of performing ion implantation in the active region to form a first ion implantation region, a second ion implantation region and a third ion implantation region on the substrate includes:

Performing ion implantation of the first doping type on the active area to form a fifth ion implantation area;

Performing ion implantation of the second doping type in the fifth ion implantation region to form a sixth ion implantation region in the fifth ion implantation region, and a portion of the fifth ion implantation region not covered by the sixth ion implantation region serves as the third ion implantation region;

Ions of the second doping type are implanted in the sixth ion implantation region to form a first ion implantation region in the sixth ion implantation region, and a portion of the sixth ion implantation region not covered by the first ion implantation region serves as the second ion implantation region.

Optionally, the steps of making the first isolation region and the second isolation region include:

Thinning is performed in the manufacturing area of the first isolation region and the second isolation region on the substrate wafer, and then a deep trench isolation that fully penetrates the substrate is manufactured to form the first isolation region and the second isolation region.

Optionally, metal wiring is performed first, and then the first isolation region and the second isolation region are manufactured.

In addition, to achieve the above objectives, the present invention also provides a photodetector, comprising the single photon avalanche diode as described above.

Compared with the prior art, the beneficial effects of the present invention include: in order to improve the imaging resolution of the SPAD array chip without reducing the overall size of the SPAD, the single SPAD proposed in the embodiment of the present invention can be divided into multiple sub-SPADs that can independently perform single-photon detection, thereby realizing position-sensitive detection of the entire SPAD and improving the resolution of the SPAD array. In the embodiment of the present invention, the SPAD is divided into preset equal parts by setting a second isolation region, so that each sub-region can be used as a sub-SPAD respectively; since the second isolation region may generate carriers near it due to leakage current and other reasons and trigger avalanche, resulting in an increase in the dark count rate, the embodiment of the present invention sets a third doping region with a doping concentration that gradually increases from the upper surface to the lower surface, so that the area where the lower surface of the first doping region is connected to the side (the side away from the second isolation region) is more prone to avalanche, while suppressing the probability of avalanche in the area of the lower surface of the first doping region close to the second isolation region, that is, using edge breakdown to improve detection. efficiency; setting the second doping region to be a doping region with the same doping type as the first doping region but with a lower doping concentration can also adjust the electric field direction of edge breakdown of the first doping region and the third doping region; that is, different from the practice of suppressing edge breakdown in traditional SPAD structures, the embodiment of the present invention uses edge breakdown to improve detection efficiency and obtains a SPAD that relies on edge breakdown, so that the SPAD can obtain a smaller size (the size of the sub-SPAD is smaller than the original SPAD) and higher performance, thereby improving the imaging resolution of the SPAD array chip and ensuring detection efficiency without reducing the overall size of the SPAD.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a cross-sectional schematic diagram of a single photon avalanche diode according to an embodiment of the present invention;

FIG2 is a top view of a single photon avalanche diode according to an embodiment of the present invention;

FIG3 is a cross-sectional schematic diagram of another single photon avalanche diode involved in an embodiment of the present invention;

FIG4 is a cross-sectional schematic diagram of a single photon avalanche diode during fabrication according to an embodiment of the present invention;

FIG5 is a schematic flow chart of a method for manufacturing a single photon avalanche diode according to an embodiment of the present invention;

FIG6 is a cross-sectional schematic diagram of another single photon avalanche diode during the manufacturing process according to an embodiment of the present invention.

Description of reference numerals:

1-first doping region; 2-second doping region; 3-third doping region; 4-fourth doping region; 5-first isolation region; 6-second isolation region; 7-substrate; 8-fifth doping region; 9-first ion implantation region; 10-second ion implantation region; 11-third ion implantation region; 12-fourth ion implantation region; 13-eighth ion implantation region.

DETAILED DESCRIPTION

In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

FIG1 is a schematic cross-sectional view of a single-photon avalanche diode according to an embodiment of the present invention, and FIG2 is a top view of a single-photon avalanche diode according to an embodiment of the present invention. Referring to FIG1 and FIG2, an embodiment of the present invention relates to a single-photon avalanche diode, the single-photon avalanche diode comprising a substrate 7 of a first doping type, in which an active region is electrically isolated by a first isolation region 5; the active region is provided with a first doping region 1 and a second doping region 2 of a second doping type, and a third doping region 3 and a fourth doping region 4 of a first doping type, the first doping type is opposite to the second doping type, the doping concentration of the first doping region 1 is higher than that of the second doping region 2, the doping concentration of the fourth doping region 4 is higher than that of the third doping region 3 (that is, higher than the maximum doping concentration of the third doping region 3) and the substrate 7, the doping concentration of the third doping region 3 gradually increases in a direction away from the upper surface of the active region (the side where the third doping region 3 extends from the surface of the active region to the inside of the active region is the upper surface of the active region), and the first doping region 1 and the fourth doping region 4 are used as an anode contact region and a cathode contact region respectively according to the doping type.

The third doping region 3 extends from the upper surface of the active region to the inside of the active region, the second doping region 2 extends from the upper surface of the third doping region 3 (the side of the third doping region 3 facing away from the upper surface of the active region is the lower surface, and the upper surface and the lower surface are opposite surfaces) to the inside of the third doping region 3, and is surrounded by the third doping region 3 whose width and depth are both greater than the second doping region 2, the first doping region 1 extends from the upper surface of the second doping region 2 (the side of the second doping region 2 facing away from the upper surface of the active region is the lower surface, and the upper surface and the lower surface are opposite surfaces) to the inside of the second doping region 2, and is surrounded by the second doping region 2 whose width and depth are both greater than the first doping region 1, the fourth doping region 4 extends from the upper surface of the active region to the inside of the active region along the entire edge of the first isolation region 5, and the side of the fourth doping region 4 facing away from the first isolation region 5 is connected to the side of the third doping region 3 close to the first isolation region 5;

A second isolation region 6 is also provided in the substrate 7, and the second isolation region 6 divides the first doping region 1, the second doping region 2, the third doping region 3 and the fourth doping region 4 into preset equal parts which are electrically isolated from each other, so that the active region is divided into sub-regions of preset equal parts, and the structure in each sub-region constitutes a sub-single photon avalanche diode (sub-SPAD).

It should be noted that FIG. 1 and FIG. 2 are schematic diagrams drawn based on the example that the preset equal parts are set to 4 equal parts and the positive projection of the active area on the upper surface of the substrate 7 is a rectangle; with reference to FIG. 2, the positive projection of the active area on the upper surface of the substrate 7 is a rectangle, and the positive projection of the second isolation region 6 on the upper surface of the substrate 7 is a cross, so that the first doping region 1, the second doping region 2, the third doping region 3 and the fourth doping region 4 are divided into 4 equal parts that are electrically isolated from each other. In a specific embodiment, the preset equal parts can be set as needed, for example, set to 2 equal parts, 3 equal parts, 4 equal parts, etc., and according to the different settings of the preset equal parts, the shape of the positive projection of the second isolation region 6 on the upper surface of the substrate 7 is also different. For example, when the preset equal parts are set to 2 equal parts, the shape of the positive projection of the second isolation region 6 on the upper surface of the substrate 7 is a narrow and long rectangle (ignoring its width, it can be regarded as a line); the shape of the positive projection of the active area on the upper surface of the substrate 7 can also be a circle or other shapes, which is not limited in this embodiment.

In a specific embodiment, the substrate 7 can be a silicon substrate; the first doping type is p-type doping (for example, doped with boron or boron difluoride), and the second doping type is n-type doping (for example, doped with phosphorus or arsenic); or, the first doping type is n-type doping, and the second doping type is p-type doping. When the first doping type is p-type doping, the first doping region 1 serves as a cathode contact region, and the fourth doping region 4 serves as an anode contact region. When the first doping type is n-type doping, the first doping region 1 serves as an anode contact region, and the fourth doping region 4 serves as a cathode contact region.

In a feasible implementation, when using SPAD to make a photodetector, the anode contact area of each sub-SPAD can be connected together, and then the cathode contact area of each sub-SPAD is respectively connected to a set of quenching circuits.

In a feasible embodiment, the first doping region 1 can be heavily doped, and the second doping region 2 can be moderately doped, so that the doping concentration of the first doping region 1 is higher than that of the second doping region 2; the fourth doping region 4 can be heavily doped, and the third doping region 3 and the substrate 7 can be moderately doped, so that the doping concentration of the fourth doping region 4 is higher than that of the third doping region 3 and the substrate 7; the third doping region 3 can achieve a gradually increasing doping concentration in the direction away from the upper surface of the active region through reverse doping.

The embodiment of the present invention mainly describes a single single-photon avalanche diode. It can be understood that more than one single-photon avalanche diode can be integrated on the same substrate 7, and other devices can also be formed. The devices are isolated by isolation regions. In this embodiment, the isolation region used to isolate the single single-photon avalanche diode from other devices is called the first isolation region 5, and the isolation region used to isolate the sub-single-photon avalanche diode in the single single-photon avalanche diode is called the second isolation region 6. The isolation region can be implemented by any isolation structure that can electrically isolate the isolated parts. For example, it can be implemented by deep trench isolation that penetrates the substrate 7 in the depth direction.

In order to improve the imaging resolution of the SPAD array chip without reducing the overall size of the SPAD, the single SPAD proposed in the embodiment of the present invention can be divided into multiple sub-SPADs that can independently perform single photon detection, thereby realizing position-sensitive detection of the entire SPAD and improving the resolution of the SPAD array. In the embodiment of the present invention, the SPAD is divided into preset equal parts by setting the second isolation region 6, so that each sub-region can be used as a sub-SPAD respectively; because the second isolation region 6 may generate carriers near it due to leakage current and other reasons and trigger avalanche, resulting in an increase in dark count rate, the embodiment of the present invention sets a third doping region 3 with a doping concentration gradually increasing from the upper surface to the lower surface, so that the area where the lower surface of the first doping region 1 is connected to the side (the side away from the second isolation region 6) is more likely to avalanche, and the probability of avalanche occurring in the area of the lower surface of the first doping region 1 close to the second isolation region 6 is suppressed, that is, edge breakdown is used to improve the detection efficiency; the second doping region 2 is set to be a doping region with the same doping type as the first doping region 1 but a lower doping concentration, and the electric field direction of the edge breakdown of the first doping region 1 and the third doping region 3 can also be regulated; that is, different from the method of suppressing edge breakdown in traditional SPAD structures, the embodiment of the present invention uses edge breakdown to improve the detection efficiency, obtains a SPAD that relies on edge breakdown, and enables the SPAD to have a smaller size (the size of the sub-SPAD is smaller than the original SPAD) and higher performance. It can be understood that since each sub-SPAD can independently detect incident photons, position-sensitive detection of the entire SPAD is achieved, so that the resolution of the SPAD array is improved by a preset multiple. For example, if the preset multiple is 4, the resolution of the SPAD array is improved by 4 times.

FIG3 is a cross-sectional schematic diagram of a single-photon avalanche diode according to another embodiment of the present invention. Referring to FIG3 , the single-photon avalanche diode according to another embodiment is different from the single-photon avalanche diode shown in FIG1 in that a fifth doping region 8 of the first doping type is further provided in the active region, the depth of the fourth doping region 4 is less than the depth of the third doping region 3, the doping concentration of the fifth doping region 8 is less than the doping concentration of the fourth doping region 4, the fifth doping region 8 extends along the entire edge of the first isolation region 5 from the upper surface of the fourth doping region 4 to the lower surface of the active region, the side portion of the fifth doping region 8 facing away from the first isolation region 5 is connected to the third doping region 3, and the depth of the fifth doping region 8 is greater than the depth of the third doping region 3.

In this embodiment, taking the first doping type as p-type doping as an example, the fifth doping region 8 is used to guide the anode potential of the SPAD to the bottom of the substrate 7, further ensuring that the direction of the electric field is toward the edge breakdown region of the first doping region 1, thereby further improving the detection efficiency of the SPAD. In addition, the fifth doping region 8 can also prevent the non-photogenerated carriers generated near the first isolation region 5 from entering the avalanche region, resulting in a higher dark count rate.

The embodiment of the present invention also relates to a method for manufacturing a single photon avalanche diode, which can be used to manufacture the single photon avalanche diode described in the above embodiment. It should be understood that the manufacture of the single photon avalanche diode described in the above embodiment is not limited to the method described below.

FIG4 is a cross-sectional schematic diagram of a single photon avalanche diode manufacturing process according to an embodiment of the present invention. FIG5 is a flow chart of a single photon avalanche diode manufacturing method according to an embodiment of the present invention. Referring to FIG1 to FIG5, in an embodiment of the present invention, the single photon avalanche diode manufacturing method includes the following steps:

Step S1: providing a substrate 7, and defining an active area on the substrate 7;

Step S2: performing ion implantation in the active area to form a first ion implantation area 9, a second ion implantation area 10, a third ion implantation area 11 and a fourth ion implantation area 12 on the substrate 7, wherein the first ion implantation area 9 extends from the upper surface of the active area to the inside of the active area, the second ion implantation area 10 extends from the upper surface of the third ion implantation area 11 to the inside of the third ion implantation area 11, and is surrounded by the third ion implantation area 11 whose width and depth are both greater than the second ion implantation area 10, the first ion implantation area 9 extends from the upper surface of the second ion implantation area 10 to the inside of the second ion implantation area 10, and is surrounded by the second ion implantation area 10 whose width and depth are both greater than the first ion implantation area 9, the fourth ion implantation area 12 extends from the upper surface of the active area to the inside of the active area along the entire edge of a side of the third ion implantation area 11 away from the second ion implantation area 10, and the side of the fourth ion implantation area 12 away from the third ion implantation area 11 reaches the edge of the active area;

Step S3: A first isolation region 5 is formed on the substrate 7 along the outer edge of the active region, and a second isolation region 6 is formed on the substrate 7. The second isolation region 6 electrically isolates the first ion implantation region 9, the second ion implantation region 10, the third ion implantation region 11 and the fourth ion implantation region 12 into preset equal parts. The first ion implantation region 9, the second ion implantation region 10, the third ion implantation region 11 and the fourth ion implantation region 12 isolated by the second isolation region 6 are respectively used as the first doping region 1, the second doping region 2, the third doping region 3 and the fourth doping region 4.

In step S2, the doping type of the first ion implantation area 9 and the second ion implantation area 10 is the second doping type, and the doping type of the third ion implantation area 11 and the fourth ion implantation area 12 is the first doping type. The doping concentration of the ions implanted in the first ion implantation area 9 is higher than the doping concentration of the ions implanted in the second ion implantation area 10. The doping concentration of the ions implanted in the fourth ion implantation area 12 is higher than the maximum doping concentration of the ions implanted in the third ion implantation area 11, and higher than the doping concentration of the substrate 7. The third ion implantation area 11 can be implanted in a reverse doping manner so that the doping concentration of the fourth ion implantation area 12 gradually increases in a direction away from the upper surface of the active area.

In a feasible implementation, in step S3, when making the first isolation region 5 and the second isolation region 6, thinning can be performed in the manufacturing area of the first isolation region 5 and the second isolation region 6 on the substrate 7 wafer (the area where the first isolation region 5 and the second isolation region 6 need to be manufactured), and then a deep trench isolation that fully penetrates the substrate 7 is manufactured to form the first isolation region 5 and the second isolation region 6. By thinning the wafer first, it is possible to penetrate the substrate 7 when manufacturing the deep trench isolation.

In one feasible implementation, in step S2, when ion implantation is performed in the active region to form the first ion implantation region 9, the second ion implantation region 10 and the third ion implantation region 11 on the substrate 7, ion implantation of the first doping type may be performed on the active region first to form a fifth ion implantation region (the region in which the first ion implantation region 9, the second ion implantation region 10 and the third ion implantation region 11 in FIG. 4 are combined, and are not marked with reference numerals); and then ion implantation of the second doping type is performed in the fifth ion implantation region to form a sixth ion implantation region in the fifth ion implantation region (the region in which the first ion implantation region 9, the second ion implantation region 10 and the third ion implantation region 11 in FIG. 4 are combined, and are not marked with reference numerals); The combined area of the sub-implantation area 9 and the second ion implantation area 10 is not marked with a reference numeral), and the portion of the fifth ion implantation area not covered by the sixth ion implantation area is used as the third ion implantation area 11, and the depth and width of the fifth ion implantation area are both greater than those of the sixth ion implantation area; then, ion implantation of the second doping type is performed in the sixth ion implantation area to form a first ion implantation area 9 in the sixth ion implantation area, and the portion of the sixth ion implantation area not covered by the first ion implantation area 9 is used as the second ion implantation area 10, and the width and depth of the sixth ion implantation area are both greater than those of the first ion implantation area 9.

FIG6 is a cross-sectional schematic diagram of a single-photon avalanche diode manufacturing process according to an embodiment of the present invention. In a feasible implementation, referring to FIG6 , in step S2, ion implantation is performed in the active region, and before the fourth ion implantation region 12 is formed on the substrate 7, ion implantation can be performed in the active region first to form a seventh ion implantation region (the region in FIG6 where the fourth ion implantation region 12 and the eighth ion implantation region 13 are combined, and not marked with a reference numeral), the seventh ion implantation region extends from the upper surface of the active region to the inside of the active region along the entire edge of the side of the third ion implantation region 11 away from the second ion implantation region 10, the side of the seventh ion implantation region away from the third ion implantation region 11 reaches the edge of the active region, and the depth of the seventh ion implantation region is greater than the depth of the third ion implantation region 11. Then, the fourth ion implantation region 12 is implanted into the seventh ion implantation region. The width of the fourth ion implantation region 12 is the same as that of the seventh ion implantation region, and the depth is lower than that of the seventh ion implantation region. The portion of the seventh ion implantation region not covered by the fourth ion implantation region 12 serves as the eighth ion implantation region 13. After manufacturing the second isolation region 6, the eighth ion implantation region 13 isolated by the second isolation region 6 is used as the fifth doping region 8.

In a feasible implementation, in step S3, metal wiring can be performed first, and then the first isolation region 5 and the second isolation region 6 can be manufactured, and the manufacturing of the first isolation region 5 and the second isolation region 6 does not need to damage the metal wiring. The metal wiring refers to connecting the single-photon avalanche diode with other devices that need to be connected using metal wires, such as connecting with a quenching circuit, a readout circuit, etc.

On the basis of the above embodiments, an embodiment of the present invention further provides a photodetector, which includes any single photon avalanche diode in the above embodiments.

It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other. For the method disclosed in the embodiment, since it corresponds to the structure disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the structural description.

It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims (10)

1. A single photon avalanche diode, comprising: A substrate of a first doping type, wherein an active region is electrically isolated by a first isolation region in the substrate; The active region is provided with a first doping region and a second doping region of a second doping type, and is further provided with a third doping region and a fourth doping region of the first doping type, the first doping type is opposite to the second doping type, the doping concentration of the first doping region is higher than that of the second doping region, the doping concentration of the fourth doping region is higher than that of the third doping region and the substrate, the doping concentration of the third doping region gradually increases in a direction away from the upper surface of the active region, and the first doping region and the fourth doping region serve as an anode contact region and a cathode contact region respectively according to the doping type; The third doping region extends from the upper surface of the active region to the inside of the active region, the second doping region extends from the upper surface of the third doping region to the inside of the third doping region, and is surrounded by the third doping region whose width and depth are both greater than the second doping region, the first doping region extends from the upper surface of the second doping region to the inside of the second doping region, and is surrounded by the second doping region whose width and depth are both greater than the first doping region, the fourth doping region extends from the upper surface of the active region to the inside of the active region along the entire edge of the first isolation region, and a side of the fourth doping region facing away from the first isolation region is connected to a side of the third doping region close to the first isolation region; A second isolation region is also provided in the substrate, and the second isolation region divides the first doped region, the second doped region, the third doped region and the fourth doped region into preset equal parts which are electrically isolated from each other, so that the active region is divided into sub-regions of the preset equal parts, and the structure in each sub-region constitutes a sub-single-photon avalanche diode. 2. The single-photon avalanche diode as described in claim 1 is characterized in that the depth of the fourth doping region is less than the depth of the third doping region, and a fifth doping region of the first doping type is also provided in the active region, the doping concentration of the fifth doping region is less than the doping concentration of the fourth doping region, the fifth doping region extends along the entire edge of the first isolation region, from the upper surface of the fourth doping region to the lower surface of the active region, the side of the fifth doping region facing away from the first isolation region is connected to the third doping region, and the depth of the fifth doping region is greater than the depth of the third doping region. 3 . The single photon avalanche diode according to claim 1 , wherein the first isolation region and the second isolation region are isolation regions formed by deep trench isolation. 4. The single-photon avalanche diode as described in claim 1 is characterized in that the orthographic projection of the active area on the upper surface of the substrate is a rectangle, and the orthographic projection of the second isolation area on the upper surface of the substrate is a cross, so as to divide the first doped area, the second doped area, the third doped area and the fourth doped area into four equal parts that are electrically isolated from each other. 5 . The single photon avalanche diode according to claim 1 , wherein the first doping type is p-type doping, and the second doping type is n-type doping. 6. A method for manufacturing a single photon avalanche diode, characterized in that it is used to manufacture the single photon avalanche diode according to any one of claims 1 to 5, comprising: Providing the substrate, and defining the active area on the substrate; Performing ion implantation in the active region to form a first ion implantation region, a second ion implantation region, a third ion implantation region and a fourth ion implantation region on the substrate, wherein the first ion implantation region extends from the upper surface of the active region to the interior of the active region, the second ion implantation region extends from the upper surface of the third ion implantation region to the interior of the third ion implantation region and is surrounded by the third ion implantation region having a width and a depth greater than that of the second ion implantation region, the first ion implantation region extends from the upper surface of the second ion implantation region to the interior of the second ion implantation region and is surrounded by the second ion implantation region having a width and a depth greater than that of the first ion implantation region, the fourth ion implantation region extends from the upper surface of the active region to the interior of the active region along the entire edge of a side of the third ion implantation region away from the second ion implantation region, and the side of the fourth ion implantation region away from the third ion implantation region reaches the edge of the active region; The first isolation region is fabricated on the substrate along the outer edge of the active region, and the second isolation region is fabricated on the substrate, wherein the second isolation region electrically isolates the first ion implantation region, the second ion implantation region, the third ion implantation region and the fourth ion implantation region into preset equal parts, and the first ion implantation region, the second ion implantation region, the third ion implantation region and the fourth ion implantation region isolated by the second isolation region serve as the first doping region, the second doping region, the third doping region and the fourth doping region, respectively. 7. The method for manufacturing a single photon avalanche diode according to claim 6, characterized in that the steps of performing ion implantation in the active region to form a first ion implantation region, a second ion implantation region and a third ion implantation region on the substrate include: Performing ion implantation of the first doping type on the active area to form a fifth ion implantation area; Performing ion implantation of the second doping type in the fifth ion implantation region to form a sixth ion implantation region in the fifth ion implantation region, and a portion of the fifth ion implantation region not covered by the sixth ion implantation region serves as the third ion implantation region; Ions of the second doping type are implanted in the sixth ion implantation region to form a first ion implantation region in the sixth ion implantation region, and a portion of the sixth ion implantation region not covered by the first ion implantation region serves as the second ion implantation region. 8. The method for manufacturing a single photon avalanche diode according to claim 6, wherein the steps of manufacturing the first isolation region and the second isolation region include: Thinning is performed in the manufacturing area of the first isolation region and the second isolation region on the substrate wafer, and then a deep trench isolation that fully penetrates the substrate is manufactured to form the first isolation region and the second isolation region. 9. The method for manufacturing a single-photon avalanche diode as claimed in claim 6, characterized in that metal wiring is firstly performed, and then the first isolation region and the second isolation region are manufactured. 10. A photodetector, comprising the single photon avalanche diode according to any one of claims 1 to 5.