A single photon avalanche diode device

Abstract

A kind of single-photon avalanche diode device, including N type diffusion layer, P type diffusion layer, P type epitaxial layer, P type substrate, annular P well area, deep trench isolation region DTI ring, avalanche amplification area, the bottom of the deep trench isolation region DTI ring is provided with P type substrate, P type epitaxial layer is arranged in the area between deep trench isolation region DTI ring and P type substrate, P type epitaxial layer top is provided with P type diffusion layer, the top of P type diffusion layer is provided with N type diffusion layer, and the junction of P type diffusion layer and N type diffusion layer is provided with avalanche amplification area.The annular P well area in the structure of the present application does not need to be connected to the bottommost substrate, which greatly reduces the process difficulty;The first P terminal and the N terminal of the present application directly form a through-type reaction junction structure, the depletion region is enlarged, and the device detection efficiency can be improved;The first P terminal and the second P terminal of the present application can be controlled by voltage to realize photoconductivity, so that more photoelectrons can be collected by the reaction junction, and the device detection efficiency can be further improved.

Description

Technical Field

[0001] This invention belongs to the field of single-photon avalanche diodes, specifically a single-photon avalanche diode device. Background Technology

[0002] In recent years, with the rise of technologies such as autonomous driving, various ranging methods, represented by laser ranging, have become a popular and attractive research area. One of the most mainstream methods is the Time-of-Flight (TOF) laser ranging image sensor. This technology uses laser as a light source and calculates the distance to the target by recording the time it takes for the laser to travel from emission to reflection off the object's surface and back to the image sensor. TOF ranging technology is characterized by high accuracy and low latency, which has led to its widespread attention.

[0003] Single-photon avalanche diode (SPAD) imaging technology is a novel imaging technique. SPAD image sensors offer high sensitivity and temporal resolution, making them well-suited for the requirements of Time-of-Flight (TOF) image sensors. A SPAD-based TOF distance image sensor can be implemented using a SPAD pixel array. This array utilizes CMOS (Complementary Metal-Oxide-Semiconductor) semiconductor integration technology to form multiple SPAD pixels, each containing an avalanche photodiode element arranged on a planar surface. SPADs possess single-photon response capability, effectively detecting weak reflected signals even at long distances or with low laser power. Current SPAD device structures have achieved significant optimization in detection efficiency. Similar SPAD device structures have been fabricated and verified by Sony. However, the DTI ring sidewalls require a complete p-type region injection from top to bottom, posing a significant manufacturing challenge. Most production equipment cannot meet this requirement, resulting in high manufacturing difficulty, high production costs, and low production efficiency. Summary of the Invention

[0004] This invention provides a single-photon avalanche diode device to overcome the deficiencies in the prior art.

[0005] This invention is achieved through the following technical solution:

[0006] A single-photon avalanche diode device includes an N-type diffusion layer, a P-type diffusion layer, a P-type epitaxial layer, a P-type substrate, an annular P-well region, a deep trench isolation region (DTI) ring, and an avalanche amplification region. The bottom of the DTI ring is provided with the P-type substrate. The region between the DTI ring and the P-type substrate is provided with the P-type epitaxial layer. A P-type diffusion layer is provided on top of the P-type epitaxial layer. An N-type diffusion layer is provided on top of the P-type diffusion layer. An avalanche amplification region is provided at the junction of the P-type and N-type diffusion layers. An annular P-well region is provided on the upper inner side of the DTI ring and on the upper outer side of the P-type epitaxial layer. The N-type diffusion layer can be connected to an N-terminal, and the P-type epitaxial layer can be directly or indirectly connected to a P-terminal.

[0007] In the single-photon avalanche diode device described above, the top portion of the N-type diffusion layer protrudes and is connected to the first conductive metal layer M through a first contact hole CT to form an N-terminal; the P-type substrate is connected to the metal layer BMG through an opening BV to form a first P-terminal.

[0008] In the single-photon avalanche diode device described above, the top portion of the N-type diffusion layer protrudes and is connected to the first conductive metal layer M through a first contact hole CT to form an N-terminal; a heavily SP-doped region is provided in the annular P-well region, and the heavily SP-doped region is connected to the second conductive metal layer M through a second contact hole CT to form a second P-terminal.

[0009] In the single-photon avalanche diode device described above, the top portion of the N-type diffusion layer protrudes and is connected to the first conductive metal layer M through a first contact hole CT to form an N-terminal; the P-type substrate is connected to the metal layer BMG through an opening BV to form a first P-terminal; a heavily SP-doped region is provided in the annular P-well region, and the heavily SP-doped region is connected to the second conductive metal layer M through a second contact hole CT to form a second P-terminal.

[0010] In the single-photon avalanche diode device described above, an annular P-channel is provided between the annular P-well region and the P-type substrate. The annular P-channel is located on the outer periphery of the P-type epitaxial layer, and the annular P-well region and the P-type substrate can be connected through the annular P-channel.

[0011] The advantages of this invention are: the annular P-well region in the structure of this invention does not need to be connected to the bottom substrate, which greatly reduces the difficulty of the process; a through-type reactive junction structure is directly formed between the first P-end and the N-end of this invention, the depletion region is expanded, and the device detection efficiency can be improved; photoconductivity can be achieved between the first P-end and the second P-end of this invention through voltage regulation, so as to collect more photoelectrons for the reactive junction, which can further improve the device detection efficiency. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0014] Figure 2 This is a schematic diagram of the structure of Embodiment 2 of the present invention;

[0015] Figure 3 This is a schematic diagram of the structure of Embodiment 3 of the present invention;

[0016] Figure 4 This is a schematic diagram of the structure of Embodiment 4 of the present invention;

[0017] Figure 5 This is a schematic diagram of the structure of Embodiment 5 of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1

[0020] like Figure 1 As shown, it includes an N-type diffusion layer 101, a P-type diffusion layer 102, a P-type epitaxial layer 103, a P-type substrate 104, an opening BV 105, a metal layer BMG 106, a P-well region 107, a first conductive metal layer M108, a first contact hole CT 109, an avalanche amplification region 110, and a deep trench isolation region DTI ring 111.

[0021] The N-type diffusion layer 101 is a high-concentration N-type diffusion layer formed on top of the P-type epitaxial layer 103 and covers the top of the P-type diffusion layer 102. The top part of the N-type diffusion layer 101 protrudes to the device surface and is connected to the first conductive metal layer M 108 through the first contact hole CT 109 to form the N-terminus of the device. The P-type diffusion layer 102 is a high-concentration P-type diffusion layer formed on top of the epitaxial layer and covers the bottom of the N-type diffusion layer 101. An avalanche amplification region 110 is provided at the junction of the N-type diffusion layer 101 and the P-type diffusion layer 102. The P-type epitaxial layer 103 can be obtained by growing and doping on the P-substrate 104. The P-well region 107 is a high-concentration P-type diffusion layer formed around the upper outer periphery of the P-type epitaxial layer 103. The periphery of the P-well region 107 is a deep trench isolation region DTI ring 111, which completely isolates the entire device from the surrounding devices. The metal layer BMG 106 at the bottom of the device is directly connected to the bottom P-type substrate 104 through the opening BV 105, forming the P-terminal of the device.

[0022] When the device is working, a voltage is applied to the N terminal formed by the first conductive metal layer M108 and the P terminal formed by the metal layer BMG 106. At this time, the voltage at the N terminal of the device is higher than the voltage at the P terminal of the device, so that the device operates in Geiger mode. When a photon arrives and is absorbed by the device, a hole-electron pair is generated. Under the action of the electric field, the hole-electron pair undergoes avalanche breakdown in the avalanche amplification region 110 through the multiplication effect, generating a large avalanche breakdown current.

[0023] Example 2

[0024] like Figure 2 As shown, it includes an N-type diffusion layer 201, a P-type diffusion layer 202, a P-type epitaxial layer 203, a P-type substrate 204, an opening BV 205, a metal layer BMG 206, a P-well region 207, a first conductive metal layer M208, a first contact hole CT 209, an avalanche amplification region 210, a deep trench isolation region DTI ring 211, and an annular P-channel 212.

[0025] N-type diffusion layer 201 and P-type diffusion layer 202 are disposed on top of P-type epitaxial layer 203. The top part of N-type diffusion layer 201 protrudes to the surface of the device and is connected to the first conductive metal layer M 208 through the first contact hole CT 209 to form the N-terminus of the device. The metal layer BMG 206 at the bottom of the device is directly connected to the bottom P-type substrate 204 through the contact hole CT 205 to form the P-terminus of the device. A ring-shaped P-channel 212 is formed by doping between the P-type substrate 204 and the P-well region 207. The ring-shaped P-channel 212 is disposed on the outer periphery of P-type epitaxial layer 203. The periphery of P-well region 207 is a deep trench isolation region DTI ring 314, which completely isolates the entire device from the surrounding devices.

[0026] When the device is working, a voltage is applied through the first conductive metal layer M 208 and the metal layer BMG 206, that is, a voltage is applied at the P terminal and the N terminal of the device, which can form an electric field in the device. When a photon arrives at the device and is absorbed by the device, a hole-electron pair is generated. The electron is transferred under the action of the electric field and enters the avalanche amplification region, resulting in avalanche breakdown.

[0027] Example 3

[0028] like Figure 3 As shown, it includes an N-type diffusion layer 301, a P-type diffusion layer 302, a P-type epitaxial layer 303, a P-type substrate 304, an opening BV 305, a metal layer BMG 306, a SP heavily doped region 307, a P-well region 308, a first contact hole CT 309, a first conductive metal layer M 310, a first contact hole CT 311, a second conductive metal layer M 312, an avalanche amplification region 313, and a deep trench isolation region DTI ring 314.

[0029] N-type diffusion layer 301 and P-type diffusion layer 302 are disposed on top of P-type epitaxial layer 303, with the top portion of N-type diffusion layer 301 protruding and connected to the first conductive metal layer M 310 through the first contact hole CT 309, forming the N-terminal of the device. P-type diffusion layer 302 is a high-concentration P-type diffusion layer formed on top of P-type epitaxial layer 303 and covers the bottom of N-type diffusion layer 301. An avalanche amplification region 313 is formed at the junction between N-type diffusion layer 301 and P-type diffusion layer 302. The metal layer BMG 306 at the bottom of the device is directly connected to the bottom P-type substrate 304 through opening BV 305, forming the P-terminal of the device. P-well region 308 is a high-concentration P-type diffusion layer formed on the device surface in a manner surrounding the outer periphery of P-type epitaxial layer 303. There is a heavily SP-doped region 307 in the middle of P-well region, which is connected through the second contact hole CT. 311 is connected to the second conductive metal layer M312 to form the second P terminal of the device. The periphery of the P-well region 308 is a deep trench isolation region DTI ring 314, which completely isolates the entire device from the surrounding devices, forming a three-terminal device.

[0030] When the device is working, a voltage is applied to the first conductive metal layer M 310, the second conductive metal layer M 312, and the metal layer BMG 306, so that the device operates in Geiger mode. At this time, the voltage at the second conductive metal layer M 312 is slightly higher than the voltage at the metal layer BMG 306, forming a photoconductor between the P-well region 308 and the P-substrate 304, which improves the electron transfer efficiency. When a photon arrives and is absorbed by the device, a hole-electron pair is generated. Under the action of the electric field, the hole-electron pair undergoes avalanche breakdown in the avalanche amplification region 313 through the multiplication effect, generating a large avalanche breakdown current.

[0031] Example 4

[0032] like Figure 4 As shown, it includes an N-type diffusion layer 401, a P-type diffusion layer 402, a P-type epitaxial layer 403, a P-type substrate 404, a SP heavily doped region 405, a P-well region 406, a first contact hole CT 407, a first conductive metal layer M 408, a second contact hole CT 409, a second conductive metal layer M410, an avalanche amplification region 411, and a deep trench isolation region DTI ring 412.

[0033] An N-type diffusion layer 401 and a P-type diffusion layer 402 are disposed on top of a P-type epitaxial layer 403, and the N-type diffusion layer 401 can cover the top of the P-type diffusion layer 402. An avalanche amplification region 411 is provided at the connection between the N-type diffusion layer 401 and the P-type diffusion layer 402. The surface of the N-type diffusion layer protrudes and is connected to the first conductive metal layer M 408 through the first contact hole CT 407 to form the N-terminus of the device. A P-well region 406 is provided on the upper outer periphery of the P-type epitaxial layer 403, which is a high-concentration P diffusion layer. An SP heavily doped region 405 is provided in the middle of the P-well region 406, which can be connected to the second conductive metal layer M 410 through the second contact hole CT 409 to form the P-terminus of the device. A deep trench isolation region DTI ring 412 is provided on the outer periphery of the P-well region 406 to completely isolate the entire device from the surrounding devices.

[0034] When the device is working, a corresponding voltage is applied to the P terminal formed by the second conductive metal layer M 410 and the N terminal formed by the first conductive metal layer M 408, so that the device operates in Geiger mode. When a photon arrives and is absorbed by the device, a hole-electron pair is generated. Under the action of the electric field, the hole-electron pair undergoes avalanche breakdown in the avalanche amplification region 411 through the multiplication effect, generating a large avalanche breakdown current.

[0035] Example 5

[0036] like Figure 5 As shown, it includes an N-type diffusion layer 501, a P-type diffusion layer 502, a P-type epitaxial layer 503, a P-type substrate 504, a SP heavily doped region 505, a P-well region 506, a first contact hole CT 507, a first conductive metal layer M 508, a second contact hole CT 509, a second conductive metal layer 510, an avalanche amplification region 511, a deep trench isolation region DTI ring 512, and an annular P-channel 613.

[0037] An N-type diffusion layer 501 and a P-type diffusion layer 502 are disposed on top of the P-type epitaxial layer 503, with the N-type diffusion layer 501 covering the top of the P-type diffusion layer 502. An avalanche amplification region 511 is provided at the junction between the N-type diffusion layer 502 and the P-type diffusion layer 502. The surface portion of the N-type diffusion layer 501 protrudes and is connected to the first conductive metal layer M 508 through the first contact hole CT 507, forming the N-terminus of the device. A P-well region 506 is provided on the upper outer periphery of the P-type epitaxial layer 503, which is a high-concentration P diffusion layer. A heavily SP-doped region 505 is provided within the P-well region 506, which can be connected to the second conductive metal layer M through the second contact hole CT 509. 510 are connected to form the P terminal of the device. A ring-shaped P channel 513 is formed between the P well region 506 and the P substrate 504 through doping. The ring-shaped P channel 513 is disposed on the outer periphery of the P-type epitaxial layer 503. A deep trench isolation region DTI ring 512 is disposed on the outer periphery of the ring-shaped P channel 513 to completely isolate the entire device from the surrounding devices.

[0038] When the device is working, a corresponding voltage is applied to the P terminal formed by the second conductive metal layer M 510 and the N terminal formed by the first conductive metal layer M 508, so that the device operates in Geiger mode. When a photon arrives and is absorbed by the device, a hole-electron pair is generated. Under the action of the electric field, the hole-electron pair undergoes avalanche breakdown in the avalanche amplification region 511 through the multiplication effect, generating a large avalanche breakdown current.

[0039] As can be seen from Examples 1-5, in Geiger mode, i.e., when the applied voltage is higher than the device breakdown voltage, when a photon arrives and is absorbed by the device, a hole-electron pair is generated. The electron enters the avalanche amplification region under the action of the electric field, and avalanche amplification occurs. There is a certain probability of generating a continuous avalanche breakdown. After processing by the pulse shaping and quenching circuit, a digital pulse signal can be generated. By detecting the time interval of pulse generation, high-precision distance information can be calculated to ensure the accuracy of the invention in use.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A single photon avalanche diode device, characterized by: The application relates to a semiconductor device, which comprises an N-type diffusion layer, a P-type diffusion layer, a P-type epitaxial layer, a P-type substrate, a ring-shaped P-well region, a deep trench isolation region DTI ring, and an avalanche amplification area.

2. A single photon avalanche diode device according to claim 1, wherein: The top portion of the N-type diffusion layer protrudes through a first contact hole CT and is connected with a first conductive metal layer M to form an N terminal; the P-type substrate is connected with a metal layer BMG through an opening BV to form a first P terminal.

3. A single photon avalanche diode device according to claim 1, wherein: The top portion of the N-type diffusion layer protrudes through a first contact hole CT and is connected with a first conductive metal layer M to form an N terminal; the ring-shaped P-well region is provided with an SP heavily doped area, and the SP heavily doped area is connected with a second conductive metal layer M through a second contact hole CT to form a second P terminal.

4. A single photon avalanche diode device according to claim 1, wherein: The top portion of the N-type diffusion layer protrudes through a first contact hole CT and is connected with a first conductive metal layer M to form an N terminal; the P-type substrate is connected with a metal layer BMG through an opening BV to form a first P terminal; the ring-shaped P-well region is provided with an SP heavily doped area, and the SP heavily doped area is connected with a second conductive metal layer M through a second contact hole CT to form a second P terminal.

5. A single photon avalanche diode device according to claim 1, wherein: The ring-shaped P-well region and the P-type substrate are provided with a ring-shaped P channel, the ring-shaped P channel is located at the outer periphery of the P-type epitaxial layer, and the ring-shaped P-well region and the P-type substrate can be connected through the ring-shaped P channel.

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