Photoelectric sensor, photoelectric detection device and electronic equipment

Abstract

The invention provides a photoelectric sensor, a photoelectric detection device and electronic equipment, and relates to the technical field of semiconductor photoelectric detection. According to the single photon avalanche diode provided by the invention, the center doping structure and the edge doping structure are separated in the diode substrate along the vertical direction and are not in the same horizontal plane; the projection distance between the center doping structure and the edge doping structure in the vertical direction is smaller than the electric field distance between the center doping structure and the edge doping structure, and a horizontal suppression electric field between the center doping structure and the edge doping structure is spatially bent into an inclined electric field under the setting condition. Therefore, when the distance between the central doping structure and the edge doping structure in the horizontal direction is limited, the protection ring can be obliquely formed between the central doping structure and the edge doping structure in the diode substrate, so that the size of the protection ring breaks through the limitation of the horizontal direction to increase the size of the protection ring; and the performance of the single-photon avalanche diode device is improved.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor optoelectronic detection, and particularly relates to an optoelectronic sensor, an optoelectronic detection device, and an electronic device. Background Art

[0002] A single photon avalanche diode (SPAD) can achieve fast detection of single photon signals, and has advantages such as high gain, fast speed, and low power consumption, and has gradually become the mainstream of single photon detection devices. Single photon avalanche diodes are widely used in many fields such as military, civilian, and commercial, especially in the field of near-infrared weak light detection, such as lidar, optical communication, astronomical ranging, fluorescence imaging, etc.

[0003] With the increasingly wide application of single photon avalanche diodes, there are increasingly high requirements for the overall performance of single photon avalanche diodes. Summary of the Invention

[0004] In view of the foregoing technical problems, the present application optimizes the internal structure of the single photon avalanche diode, so that a relatively large guard ring can be formed as much as possible under the design requirements of a small size, in order to improve the electrical performance of the small-size single photon avalanche diode.

[0005] In a first aspect, the present application provides an optoelectronic sensor, which includes a diode substrate, an avalanche pixel unit, and an isolation structure. The diode substrate has opposite first and second surfaces in the vertical direction. The avalanche pixel unit is disposed in the diode substrate, and the isolation structure is used to isolate the avalanche pixel unit. The avalanche pixel unit includes a central electrode, an edge electrode, a central doping structure, and an edge doping structure. Among them, the edge doping structure is formed on the first surface or the second surface and is electrically connected to the corresponding edge electrode, and the central electrode is disposed on the second surface. The central doping structure includes a first central structure and a connection structure, where the doping type of the first central structure is different from that of the edge doping structure and is far from the surface where the edge doping structure is located, and the connection structure is used to electrically connect the central electrode and the first central structure. The first central structure is used to form an avalanche region in the vertical direction and form a lateral inhibition electric field with the edge doping structure. The first central structure and the edge doping structure are separated both in the horizontal direction and in the vertical direction, so that the electric field path length of the lateral inhibition electric field is greater than the projection distance of the first central structure and the edge doping structure in the vertical direction.

[0006] In a second aspect, multiple embodiments of the present specification provide an optoelectronic detection device, which includes the optoelectronic sensor according to any implementation manner of the first aspect. The optoelectronic detection device obtains relevant information by sensing the electrical signal generated corresponding to the received optical signal of the optoelectronic sensor.

[0007] In a third aspect, multiple embodiments of this specification provide an electronic device, including the photoelectric detection device described in the second aspect. The electronic device is configured to perform corresponding functions according to relevant information obtained by sensing an electrical signal with the photoelectric detection device.

[0008] In the photoelectric sensor, photoelectric detection device, and electronic device provided by the embodiments of the present application, the central doping structure and the edge doping structure are separated vertically within the diode substrate rather than on the same horizontal plane, such that the projection distance of the central doping structure and the edge doping structure in the vertical direction is less than the electric field distance between the central doping structure and the edge doping structure. As a result, the "horizontal suppression electric field" between the central doping structure and the edge doping structure is bent into an inclined electric field in space in this setting. Thereby, when the horizontal distance between the central doping structure and the edge doping structure is limited, the guard ring can be formed inclinedly between the central doping structure and the edge doping structure in the diode substrate, enabling the size of the guard ring to break through the horizontal limitation to increase the size of the guard ring, and further improving the performance of the single-photon avalanche diode device. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other relevant drawings can also be obtained based on these drawings.

[0010] Figure 1 It is a schematic diagram of the functional modules of the electronic device provided by some embodiments of the present application.

[0011] Figure 2 It is a schematic diagram of the functional modules of the photoelectric detection device provided by some embodiments of the present application.

[0012] Figure 3 It is a top view structural diagram of the photoelectric sensor in the related art of the present application.

[0013] Figure 4 In the related art of the present application Figure 3 It is a schematic diagram of the cross-sectional structure of the photoelectric sensor shown.

[0014] Figure 5 It is a schematic diagram of the cross-sectional structure of the photoelectric sensor provided by some embodiments of the present application.

[0015] Figure 6 It is a schematic diagram of the cross-sectional structure of the photoelectric sensor provided by some embodiments of the present application.

[0016] Figure 7Schematic cross-sectional structure diagram of a photoelectric sensor provided by some embodiments of the present application.

[0017] Figure 8 Schematic cross-sectional structure diagram of a photoelectric sensor provided by some embodiments of the present application.

[0018] Figure 9 Schematic cross-sectional structure diagram of a photoelectric sensor provided by some embodiments of the present application.

[0019] Figure 10 Schematic cross-sectional structure diagram of a photoelectric sensor provided by some embodiments of the present application.

[0020] Figure 11 Schematic cross-sectional structure diagram of a photoelectric sensor provided by some embodiments of the present application.

[0021] Figure 12 Provided by some embodiments of the present application Figure 10 Schematic top view structure diagram of the photoelectric sensor shown.

[0022] Figure 13 Provided by some embodiments of the present application Figure 6 Or Figure 7 Schematic top view structure diagram of the photoelectric sensor shown.

[0023] Figure 14 Schematic top view structure diagram of a photoelectric sensor provided by some embodiments of the present application.

[0024] Figure 15 Schematic top view structure diagram of a photoelectric sensor provided by some embodiments of the present application.

[0025] Figure 16 Schematic top view structure diagram of a photoelectric sensor provided by some embodiments of the present application.

[0026] Figure 17 Schematic top view structure diagram of a photoelectric sensor provided by some embodiments of the present application.

[0027] Among them, 10 is an electronic device; 100 is an optoelectronic detection device; 110 is a processing module; 130 is a receiving component; 131 is a receiving optical device; 140 is a transmitting component; 141 is a driver; 142 is a light source; 143 is a transmitting optical device; 200 is an optoelectronic sensor; 210 is a diode substrate; 211 is a first surface; 212 is a second surface; 220 is an avalanche pixel unit; 221 is a central doping structure; 2211 is a first central structure; 2212 is a connecting structure; 2213 is a second central structure; 222 is an edge doping structure; 2221 is a conductive doping structure; 223 is a central electrode; 224 is an edge electrode; 225 is an avalanche region; 226 is a guard ring; 227 is a pixel sub-unit; 228 is a lightly doped structure; 229 is an isolation trench; 230 is an isolation structure; 231 is a deep trench isolation layer; 2311 is a metal isolation structure; 2312 is an insulating sidewall; 232 is a shallow trench insulation layer; 240 is a light-absorbing hole; 300 is a storage medium; 400 is a processor; 500 is an application module. Detailed implementation manners

[0028] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, the following will, in combination with the accompanying drawings and specific embodiments, provide a detailed description of an optoelectronic sensor, an optoelectronic detection device, and an electronic device proposed according to the present invention.

[0029] The foregoing and other technical contents, features, and effects of the present invention can be clearly presented in the following detailed description of specific embodiments in conjunction with the accompanying drawings. However, the accompanying drawings are only for reference and illustration purposes and are not used to limit the technical solutions of the present invention.

[0030] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise", or any other variant are intended to cover non-exclusive inclusion, so that an article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of another identical element in the article or device including the said element. Exemplary application scenarios:

[0031] Please refer to Figure 1。The electronic device 10 includes a photoelectric detection device 100. The photoelectric detection device 100 can detect an external object within a detection range to obtain three-dimensional information of the external object. The detection range can be defined as the three-dimensional space range within which the photoelectric detection device 100 can effectively perform three-dimensional information detection, and can also be referred to as the field of view angle of the photoelectric detection device 100. The three-dimensional information is, for example but not limited to, one or more of the proximity information of the external object, the depth information of the surface of the external object, the distance information of the external object, and the spatial coordinate information of the external object.

[0032] The electronic device 10 may include an application module 500, and the application module 500 is configured to perform a preset operation or implement a corresponding function according to the detection result of the photoelectric detection device 100. For example but not limited to: it can determine whether an external object appears within a preset detection range in front of the electronic device 10 according to the proximity information of the external object; or, it can control the movement of the electronic device 10 to avoid obstacles according to the distance information of the external object; or, it can implement 3D modeling, face recognition, machine vision, etc. according to the depth information of the surface of the external object. The electronic device 10 may further include a storage medium 300, and the storage medium 300 can provide support for the storage requirements of the photoelectric detection device 100 during operation, and one or more processors 400 execute to control relevant components to implement corresponding functions.

[0033] Optionally, in some embodiments, the photoelectric detection device 100 may be a dToF measurement device for three-dimensional information sensing based on the principle of direct time of flight (dToF).

[0034] In some other embodiments, the photoelectric detection device 100 may also be an iToF measurement device for three-dimensional information sensing based on the principle of indirect time of flight (iToF). The iToF measurement device obtains the three-dimensional information of the external object by comparing the phase difference between when the sensing beam is emitted and when it is reflected back and received.

[0035] In the following embodiments of the present application, the photoelectric detection device 100 is mainly taken as an example of a distance measurement device for illustration.

[0036] Please refer to Figure 2 。The photoelectric detection device 100 may include a transmitting component 140, a receiving component 130, and a processing module 110. The transmitting component 140 includes a driver 141, a light source 142, and a transmitting optical device 143. The processing module 110 can be coupled to the processor of the electronic device, and the transmitting component 140 and the receiving component 130 are respectively coupled to the processing module 110.

[0037] The transmitting component 140 is configured to emit a sensing optical signal towards a measurement scene for three-dimensional detection of external objects within the measurement scene. Among them, part of the sensing optical signal will be reflected by the external objects in the measurement scene and return. The reflected sensing optical signal carries the three-dimensional information of the external object. And a part of the reflected sensing optical signal can be sensed by the receiving component 130 for obtaining the three-dimensional information of the external object.

[0038] The receiving component 130 is configured to sense an optical signal from the measurement scene and output a corresponding optical induction signal. By analyzing the optical induction signal, distance detection of external objects within the measurement scene can be achieved. It can be understood that the optical signal sensed by the receiving component 130 can be photons. For example, the photons sensed by the receiving component 130 can include the photons of the sensing optical signal reflected by the external objects in the measurement scene and the photons of the ambient light of the measurement scene. The processing module 110 is configured to analyze and process the optical induction signal to obtain the moment when the sensing optical signal is sensed by the receiving component 130, and obtain the three-dimensional information of the external object according to the time difference between the emission moment and the sensed moment of the reflected sensing optical signal.

[0039] The receiving component 130 may include a photoelectric sensor 200 and receiving optics 131. Optionally, the photoelectric sensor 200 may be a photoelectric sensor composed of a single photosensitive pixel or multiple photosensitive pixels. The photosensitive pixel is used to receive an optical signal from the measurement scene and output a corresponding optical induction signal. One photosensitive pixel includes at least one photoelectric detection device. The photoelectric detection device is configured to sense the received optical signal and convert it into a corresponding electrical signal for output as the optical induction signal. The photoelectric detection device may be composed of a single-photon avalanche diode (Single Photon Avalanche Diode, SPAD).

[0040] The SPAD is a solid-state photoelectric detection device whose operating voltage is above the breakdown voltage and belongs to an avalanche photodiode in Geiger mode. Different from traditional photoelectric detection devices, the SPAD has the ability to resolve and detect individual photons. The incidence of a single photon may induce the SPAD to generate an avalanche behavior with a certain probability, and then generate an obvious avalanche current. By cooperating with the readout circuit, the detection of photons can be achieved. Application overview:

[0041] In practical applications, SPADs generally exhibit an array arrangement. Each SPAD serves as a photosensitive pixel (also denoted as an avalanche pixel unit or pixel element) to form a photoelectric sensor. To isolate each SPAD, an isolation structure (generally in the form of a grid and denoted as an isolation grid / isolation grille, hereinafter uniformly denoted as an isolation structure) is provided between each avalanche pixel unit.

[0042] To further illustrate the photoelectric sensor constructed by SPADs, the present application also provides a top view structural schematic diagram of a photoelectric sensor ( Figure 3 ).

[0043] The photoelectric sensor 200 can be presented as a semiconductor structure formed based on a diode substrate 210. That is, the diode substrate 210 can refer to the base material for forming the photoelectric sensor 200. The specific structure of the photoelectric sensor 200 can be formed within or on the diode substrate 210 based on semiconductor processes (such as etching, deposition, etc.).

[0044] As Figure 2 shown, the photoelectric sensor 200 can include multiple avalanche pixel units 220 and an isolation structure 230 for isolating the avalanche pixel units. Among them, the isolation structure 230 can be disposed around each avalanche pixel unit 220 to form a pixel space for accommodating the avalanche pixel units 220 and isolate each pixel space. The aforementioned avalanche pixel units 220 and the isolation structure 230 can be formed within the diode substrate 210 based on semiconductor processes (such as etching, deposition, doping, etc.).

[0045] Similar to the imaging principle of traditional pixel units, different pixel units in the aforementioned photoelectric sensor 200 can be mapped to different positions in space. When the avalanche pixel unit 220 receives an optical signal (such as a single-photon optical signal), an avalanche phenomenon will occur inside it to generate a corresponding electrical signal. Based on the presence or absence of the electrical signal and the correspondence between the pixel unit and space, combined with the relevant calculation principle of the aforementioned time of flight, three-dimensional imaging of an external object can be achieved. For details, reference can be made to the related technology and will not be elaborated here.

[0046] In addition, considering the application scenarios of the avalanche pixel unit 220, in the photoelectric sensor 200, a filter structure and a light condensing structure can also be provided upstream of the light incident optical path of the avalanche pixel unit 220 to avoid ambient light interference and improve the light beam sensing ability.

[0047] Specifically, inside the aforementioned avalanche pixel unit 220, its most basic structure includes a P region and an N region, forming a PN junction between them. In addition, to achieve avalanche, additional doping is usually required near the junction region to achieve avalanche under relatively low bias voltages. To realize in-plane device integration, the P region and N region of the PN junction need to be connected out from the surface respectively.

[0048] For further illustration of the basic functions of the avalanche pixel unit 220, this application also takes a planar NP-type avalanche diode device as an example and provides Figure 3 a schematic diagram of the cross-sectional structure of the photoelectric conversion device shown at AA ( Figure 4 ). Among them, for the convenience of subsequent description, Figure 4 the stacking direction of the device (i.e., the longitudinal direction in the figure) is denoted as the vertical direction, and the extension direction of AA (the direction in the plane perpendicular to the vertical direction, i.e., the horizontal direction in the figure) is denoted as the horizontal direction.

[0049] To describe the specific internal structure of the avalanche pixel unit 220, this application only shows Figure 4 one avalanche pixel unit 220 and the isolation structure 230 on both sides thereof in

[0050] Continuing with the aforementioned NP-type avalanche diode device, Figure 4 the diode substrate 210 of the photoelectric sensor 200 shown can be configured as a P-type doped substrate. Inside the avalanche pixel unit 220, there can be multiple doped regions and electrodes (which can also be called leads, CT lines) electrically connected to the corresponding doped regions on the surface of the diode substrate 210. Specifically, inside the avalanche pixel unit 220, an N region, a P+ region arranged in the central area, and a P- region close to the isolation structure 230 are included. Among them, + and - represent doping concentrations.

[0051] An avalanche region is formed at the contact interface between the N region and the P+ region, and the P- region is separated from the N region. The electrodes that can be led out from the N region and the P- region can sense the avalanche situation of the device under the action of an external drive circuit. Among them, the P+ region and the P- region are generally formed based on a P-type substrate and are additionally doped for better device formation, and their actual structures can also be without additional doping.

[0052] Figure 4 In , a longitudinal electric field can be formed between the P+ region and the N region in the stacking direction of the semiconductor device (i.e., the vertical direction in the figure, hereinafter simply referred to as the vertical direction), and a transverse electric field can be formed between the P- region and the N region in the array direction of the semiconductor device (i.e., the horizontal direction in the figure, hereinafter simply referred to as the horizontal direction).

[0053] The longitudinal electric field drifts the carriers generated by incident photons to the avalanche region. At the same time, the strong longitudinal electric field in the avalanche region causes the carriers to collide and ionize with the lattice. When the width of the strong electric field is large enough, a self-sustaining avalanche effect can occur. For the transverse electric field formed by the P- region and the N region, it is necessary to suppress its magnitude and increase the transverse avalanche breakdown voltage of the PN junction, so that the avalanche of the carriers generated by the incident light occurs in the longitudinal electric field region, that is, the main junction region. Among them, the substrate region formed by the separation of the P- region and the N region in the horizontal direction can be denoted as a guard ring (Guide-Ring, GR).

[0054] In actual use, with the continuous development of the manufacturing process and the continuous improvement of device precision requirements, the cell size of the SPAD is continuously reduced to increase the imaging resolution. However, based on the aforementioned sensing principle of the SPAD, the smaller the size, the more likely it is to cause conflicts in the internal structure of the device. For example, the conflict between the size of the intermediate avalanche region and the width of the lateral depletion region.

[0055] In related technologies, to achieve a small-size SPAD cell, the common practice is to scale down proportionally. However, some size parameters of the internal structure of the SPAD are closely related to its performance. Therefore, when scaling down proportionally, multiple technical problems will occur (such as the side breakdown problem will become serious, thus affecting the device performance). Specifically, the problems / limitations can be presented in the following aspects: ① Avalanche region size limitation: When the avalanche region becomes smaller, the probability of edge carriers entering the avalanche region will decrease, resulting in a decrease in the Photon Detection Efficiency (PDE). Especially in the case of small-sized pixels. Among them, each electrode led out from the surface of the diode substrate often has certain size requirements (such as 0.3 - 0.4um). Therefore, in the case of small pixel sizes, the size of the avalanche region and other regions is further restricted, resulting in the PDE being affected.

[0056] ② Guard ring size limitation: Similar to the aforementioned avalanche region, to suppress the lateral electric field, the spacing distance between the P region and the N region can be increased to increase the guard ring size, making the lateral PN junction tend to be a graded junction. That is, generally, under a fixed bias voltage, a sufficient depletion region width needs to be maintained. Considering the aforementioned size limitations, if the photosensitive pixel is designed to be 1um, the space left for the guard ring is only about 0.3um on each side. This is a relatively dangerous design that may lead to the possibility of side avalanche, affecting the reliability. In larger-sized pixels, such as pixels with a pitch of 10 - 15um, the guard ring design is often within 1um - 3um or more.

[0057] Therefore, to avoid the conflict of size limitations of each device when the device size is reduced, resulting in the guard ring formed by the remaining space being too compact, leading to side breakdown and reliability problems, is a technical problem that needs to be urgently solved by those skilled in the art.

[0058] In the single-photon avalanche diode (i.e., the photoelectric sensor) provided by the present application, the central doping structure and the edge doping structure are separated vertically within the diode substrate rather than on the same horizontal plane, so that the projection distance of the central doping structure and the edge doping structure in the vertical direction is less than the electric field distance between the central doping structure and the edge doping structure, and the "horizontal suppression electric field" between the central doping structure and the edge doping structure is bent into an inclined electric field in space in this setting. Thus, when the horizontal distance between the central doping structure and the edge doping structure is limited, the guard ring can be formed obliquely between the central doping structure and the edge doping structure in the diode substrate, enabling the size of the guard ring to break through the horizontal limit to increase the size of the guard ring, thereby improving the performance of the single-photon avalanche diode device.

[0059] The following will combine Figures 5 to 17 to describe the photoelectric sensor provided by the present application in detail. Exemplary optoelectronic sensor:

[0060] To further illustrate the specific structure of the photoelectric sensor provided by the present application, the present application also provides schematic diagrams of the structures of various photoelectric sensors. Among them, Figures 5 to 11 are respectively schematic diagrams of the cross-sectional structures of different photoelectric sensors.

[0061] As described above, the core point of the photoelectric sensor provided by the present application lies in the separation of the central doping structure and the edge doping structure in space. Among them, the central doping structure is electrically connected to the central electrode, and the edge doping structure can be electrically connected to the edge electrode. Driven by the central electrode, the multilayer doping structures inside the central doping structure form a longitudinal electric field, and an avalanche region is formed at the structure (the avalanche region formed with the doping substrate if not multilayer-doped can also be regarded as the avalanche region inside this structure).

[0062] To illustrate the core mechanism of the present application in detail, the following will combine Figure 5 for a detailed description.

[0063] Please refer to Figure 5 , similar to the foregoing Figure 4 , Figure 5 also presents a schematic diagram of the cross-sectional structure of a photoelectric sensor 200 including an avalanche pixel unit 220. That is, Figure 5 the photoelectric sensor 200 in

[0064] also includes a diode substrate 210, an avalanche pixel unit 220, and an isolation structure 230. Among them, the avalanche pixel unit 220 and the isolation structure 230 are also formed in the diode substrate 210 based on semiconductor processes, and the avalanche pixel unit 220 is also formed in the pixel space formed by the isolation structure 230. Figure 3 , 4Similar to the description in [reference], the diode substrate 210 can refer to the base material forming the photoelectric sensor 200, which generally includes two parts: a substrate and an epitaxial layer. Among them, the substrate is the base material in the semiconductor manufacturing process, and the epitaxial layer can be a structure grown on the substrate.

[0065] This application does not limit the specific type of the photoelectric sensor 200, and appropriate substrates and epitaxial layers (i.e., the diode substrate 210) can be selected according to actual needs. For example, the substrate can be a silicon-based substrate, a germanium-based substrate, or a III-V substrate (such as an InP substrate). The substrate can be a high-purity substrate or a doped substrate. Exemplarily, the substrate can be an N-type semiconductor substrate or a P-type semiconductor substrate formed by doping. The epitaxial layer is similar to the substrate. In the subsequent description of this case, the epitaxial layer and the substrate are regarded as a whole and not described separately.

[0066] For the convenience of describing the structure formed in the diode substrate 210, the two surfaces of the diode substrate 210 opposite to each other in the vertical direction can be respectively denoted as the first surface 211 and the second surface 212. Considering the connection relationship between the diode substrate 210 and the metal wire layer (also called the metal wiring layer, the back-end process layer, etc.) in the photoelectric sensor 200, the second surface 212 of the diode substrate 210 can be the side bonded to the metal wire layer, that is, the electrodes in the avalanche pixel unit 220 are basically formed on the second surface 212 and are electrically connected to the metal wire layer through the corresponding electrodes.

[0067] Regarding the connection relationship between the photoelectric sensor 200 and other hierarchical structures, this application does not make any restrictions. For example, when the photoelectric sensor 200 adopts a back-illuminated light structure, the aforementioned first surface 211 generally faces the incident light, and a filter layer and a light collection layer are generally arranged upstream of the incident light.

[0068] The isolation structure 230 is generally the main part of the isolation structure in the diode substrate 210, that is, the isolation structure 230 can block the lateral crosstalk between different avalanche pixel units 220, so that the avalanche pixel unit 220 only reflects the single-photon beam situation in its corresponding space. Correspondingly, the isolation structure 230 is set based on the aforementioned setting requirements, and generally needs to form pixel regions that are isolated from each other and used to accommodate the avalanche pixel units 220. Considering that the avalanche pixel unit 220 generally forms electrodes on the second surface 212 and its main structure is often arranged close to the second surface 212, the isolation structure 230 often needs to extend from the inside of the diode substrate 210 close to the first surface 211 (or directly from the first surface 211, that is, Figure 4 , 5 in which the isolation structure 230 directly penetrates the diode substrate 210) to the second surface 212 to isolate each avalanche pixel unit 220.

[0069] The isolation structure 230 is generally constructed using deep isolation trench (DTI / W-DTI) technology. Metal is filled inside the formed deep isolation trench, and isolation layers are formed on both sides of the metal to improve signal isolation and light reflection isolation capabilities.

[0070] Similar to the Figure 4 structure shown above, Figure 5 in the avalanche pixel unit 220, it can include a central doping structure 221, an edge doping structure 222, a central electrode 223, and an edge electrode 224. Among them, the central doping structure 221 is electrically connected to the central electrode 223, and the edge doping structure 222 is electrically connected to the edge electrode 224.

[0071] Specifically, the central doping structure 221 is electrically connected to the central electrode 223 and is driven by the central electrode 223. The edge doping structure 222 is electrically connected to the edge electrode 224 and is driven by the edge electrode 224. The multi-layer doping structure inside the central doping structure 221 driven by the central electrode 223 forms a longitudinal electric field, and an avalanche region 225 is formed at the structure (the avalanche region directly formed with the doped substrate without multi-layer doping can also be regarded as the avalanche region 225 within this structure). Among them, the avalanche region 225 can form an avalanche signal in response to a single-photon beam and output at the central electrode 223 and the edge electrode 224.

[0072] Specifically, the part with a different doping type inside the central doping structure 221 and the part with the same doping type as the edge doping structure 222 inside the central doping structure 221 or in the diode substrate 210 (such as the substrate) form a PN junction (which can also be extended to a PIN junction) in the vertical direction to form the avalanche region 225.

[0073] Continuing with the aforementioned device performance requirements, the central doping structure 221 and the edge doping structure 222 are separated horizontally along the second surface 212 to form a guard ring 226. There is an electric field channel from the central doping structure 221 to the edge doping structure 222 in the diode substrate 210 to form a lateral suppression electric field between the central electrode 223 and the edge electrode 224.

[0074] In addition, the central doping structure 221 and the edge doping structure 222 are generally formed based on ion implantation / deposition processes. The specific type configuration is related to the type of the photoelectric sensor 200 itself and the selection of the aforementioned diode substrate 210, and can be adjusted adaptively, which will not be elaborated here.

[0075] Based on the connection relationship between the foregoing second surface 212 and the metal wire layer, the foregoing central electrode 223 is formed on the second surface 212. The edge electrode 224 can generally also be formed on the second surface 212, and can also be formed on the first surface 211. Correspondingly, based on the working principle of the edge doping structure 222, the edge doping structure 222 can be formed on the surface where the edge electrode 224 is located. Specifically, Figure 5 The left edge electrode 224 is disposed on the second surface 212, and the right edge electrode 224 is disposed on the first surface 211.

[0076] In this application, the internal structure of the central doping structure 221 is further optimized, so that the central doping structure 221 (the doping structure that forms the avalanche region) is not directly formed at the second surface 212, but its interior includes a first central structure 2211 and a connection structure 2212. The first central structure 2211 is sunk into the diode substrate 210, and then electrically connected to the first central structure 2211 through the connection structure 2212. Among them, the first central structure 2211 can be a doping structure in the central doping structure 221 that has a different doping type from the edge doping structure 222 and is used to form the avalanche region. That is, the first central structure 2211 is used to form the avalanche region 225 in the vertical direction and form a lateral suppression electric field (i.e., the protection ring 226) with the edge doping structure 222.

[0077] Based on the foregoing setting, the first central structure 2211 is far from the surface where the edge doping structure 222 is located, so that the first central structure 2211 and the edge doping structure 222 are separated both horizontally and vertically, and the electric field path length of the lateral suppression electric field is greater than the projection distance of the first central structure 2211 and the edge doping structure 222 in the vertical direction.

[0078] Specifically, in combination with the foregoing separation situation, the horizontal distance between the first central structure 2211 and the edge doping structure 222 is d1 (i.e., the projection distance of the central doping structure and the edge doping structure in the vertical direction is d1), and the vertical distance is d2 (i.e., the projection distance of the central doping structure and the edge doping structure in the horizontal direction is d2).

[0079] Based on the formation principle of the foregoing horizontal suppression electric field, the "horizontal suppression electric field" will be formed at the edges where the first central structure 2211 and the edge doping structure 222 are close to each other. Considering that the first central structure 2211 and the edge doping structure 222 are separated in the horizontal direction and the vertical direction, the path from the first central structure 2211 to the edge doping structure 222 passes through the horizontal direction and the vertical direction, and the "horizontal suppression electric field" formed by it is an inclined electric field in the space bending. Then the protection ring formed based on the horizontal suppression electric field is also bent by this setting.

[0080] Among them, the distance of the aforementioned inclined electric field (electric field distance) can be characterized as the distance between the edge of the central doping structure and the edge of the edge doping structure. Based on the aforementioned separation situation, the electric field path length d e is approximately . Thus, the size of the protection ring is also approximately .

[0081] Based on the aforementioned size formula of the protection ring, the size of the protection ring is no longer only affected by the horizontal distance d1. When the horizontal distance between the central doping structure and the edge doping structure is limited, the size of the protection ring can be increased by the vertical distance d2

[0082] Therefore, based on the aforementioned design that the central doping structure (the first central structure therein) and the edge doping structure are staggered vertically in the diode substrate and not on the same horizontal plane, the vertical projection distance between the central doping structure and the edge doping structure is less than the electric field distance between the central doping structure and the edge doping structure, so that the "horizontal suppression electric field" between the central doping structure and the edge doping structure is spatially bent into an inclined electric field in this setting. Thus, when the horizontal distance between the central doping structure and the edge doping structure is limited, the protection ring can be formed inclined between the central doping structure and the edge doping structure in the diode substrate, so that the size of the protection ring breaks through the horizontal limitation to increase the size of the protection ring, thereby improving the performance of the photoelectric sensor device

[0083] To further describe the aforementioned situation set in the photoelectric sensor, the following will be combined with Figures 6 to 10 for illustration. Among them, Figures 6 to 10 shows the internal structure when the edge doping structure is formed on the second surface Figure 11 shows the internal structure when the edge doping structure is formed on the first surface

[0084] Considering that the first central structure 2211 is formed in the diode substrate 210, in order to avoid the direct formation of avalanche between the first central structure 2211 and the doped substrate surrounding the first central structure 2211, the central doping structure 221 may further include a second central structure 2213. The doping type of the second central structure 2213 is the same as that of the edge doping structure 222 (the doping concentration is generally higher than that of the substrate) and forms an avalanche region 225 with the first central structure 2211

[0085] In Figures 6 to 10 the photoelectric sensor shown, different from Figure 5The lead-like structure shown, in which the connection structure 2212 shown can be configured as a doped structure with electrical conductivity, and the doping type of the connection structure 2212 is the same as that of the first central structure 2211. Specifically, one end of the connection structure 2212 is formed on the second surface 212, and the other end is formed on the side of the first central structure 2211 close to the second surface 212.

[0086] Considering the foregoing Figures 6 to 10 In the above, the edge doping structure 222 is formed at the second surface 212. At the same time, based on the property that the doping type of the connection structure 2212 is the same as that of the first central structure 2211, a lateral inhibition electric field may also be formed between the connection structure 2212 and the edge doping structure 222.

[0087] To avoid this situation, the foregoing connection structure 2212 can be optimized through the doping concentration and the two side layers of the device size. Among them, Figure 6 can reflect the situation of adjusting the connection structure 2212 based on the doping concentration, Figure 7 can reflect the situation of adjusting the connection structure 2212 based on the size. And Figure 8 and Figure 9 The structure of can adopt Figure 6 the connection structure shown, or can also adopt Figure 7 the connection structure shown (the structure shown in the figure is adopted Figure 7 shown).

[0088] At the doping concentration level, the doping concentration of the connection structure near the horizontal edge of the first central structure is lower than the doping concentration of the first central structure (that is, the doping concentration near the edge of the connection structure close to the edge doping structure is low / undoped), so that no lateral inhibition electric field is formed between its side and the edge doping structure 222.

[0089] At the size level, the size of the connection structure in the horizontal direction can be directly reduced, so that the size of the connection structure in the horizontal direction is smaller than the size of the first central structure. Thus, the horizontal distance between the connection structure and the edge doping structure is also further increased to approximate the electric field path length between the first central structure and the edge doping structure.

[0090] In addition, to prevent the edge doping structure from extending beyond the connection structure when extending from the second surface and directly forming a lateral inhibition electric field with the first central structure in the horizontal direction. The "depth" of the edge doping structure should be less than the "depth" of the connection structure, that is, the edge doping structure extends from the second surface into the diode substrate and the vertical extension depth of the edge doping structure is less than the vertical extension depth of the connection structure.

[0091] Specifically, please refer to Figure 6, the horizontal dimension of the connection structure 2212 based on doping concentration adjustment may not be additionally defined. Generally, the dimension of the connection structure 2212 in the horizontal direction is approximately the same as or smaller than that of the first central structure 2211 in the horizontal direction. For example, Figure 6 the dimension of the connection structure 2212 in Figure 6 is the same as that of the first central structure 2211.

[0092] As mentioned above, to avoid edge breakdown of the connection structure 2212, the side of the connection structure 2212 close to the edge doping structure 222 has a lower doping concentration / is not doped. At the same time, to ensure the electrical connection between the central electrode 223 and the first central structure 2211, the doping concentration of the connection structure 2212 in the central electrode 223 region is relatively high to meet the electrical connection requirements, and decreases along the direction away from the central electrode (which can also be denoted as along the direction close to the side), so that its edge doping concentration is relatively low. Specifically, reference can be made to Figure 6 the connection structure 2212 in Figure 6 , where the internal pattern filling is deeper in the central region and gradually becomes shallower at the edge.

[0093] As an alternative embodiment, an insulating layer can also be directly provided on the side of the connection structure 2212 close to the edge doping structure 222 to avoid side breakdown.

[0094] In addition, in the vertical direction, the doping concentration of the connection structure 2212 can also be adjusted. For example, the doping concentration of the connection structure 2212 can increase along the direction towards the first central structure 2211 in the vertical direction to form a smooth transition.

[0095] Thus, the conductivity of the aforementioned connection structure 2212 can be adjusted by doping concentration. Considering the change direction of its doping concentration, the first central structure 2211 is still the region with the highest doping concentration in the vertical direction, and no new connection interface is formed in the horizontal direction. Even if a lateral suppression electric field is formed at the position where the edge doping structure 222 and the connection structure 2212 close to the electrode connection point, the electric field path length is still greater than its projection distance to ensure the size of the protection ring.

[0096] Specifically, please refer to Figure 7 , the doping concentration of the connection structure 2212 based on size adjustment is not additionally defined at the doping concentration level, and its doping concentration is generally similar to / relatively lower than that of the first central structure 2211. In some cases, to improve the conductivity, the doping concentration of the connection structure 2212 can even be higher than that of the first central structure 2211.

[0097] To avoid the first central structure 2211 and the edge doping structure 222 from overlapping in the vertical direction, when the edge doping structure 222 extends from the second surface 212 into the diode substrate 210, the extension depth h2 of the edge doping structure 222 in the vertical direction is less than the extension depth h1 of the connection structure 2212 in the vertical direction.

[0098] Thus, the foregoing setting can ensure that the edge doping structure 222 and the first central structure 2211 are staggered in the vertical direction to ensure the electric field path length d e is greater than the projection distance d2 of the central doping structure 221 and the edge doping structure 222 in the vertical direction.

[0099] In addition, the inward contraction of the foregoing connection structure 2212 can increase the distance d3 between the edge doping structure 222 and the connection structure 2212 in the horizontal direction. Considering that the central doping structure 221 is generally large and the connection structure 2212 only needs to ensure the electrical connection between the second surface 212 and the first central structure 2211, the foregoing inward contraction can further ensure that the distance d3 between the edge doping structure 222 and the connection structure 2212 in the horizontal direction is not less than the electric field path length d e .

[0100] Thus, even if a horizontal suppression electric field can be formed between the edge doping structure 222 and the connection structure 2212 in the horizontal direction, its electric field path length is still less than the electric field path length between the edge doping structure 222 and the first central structure 2211.

[0101] In some embodiments, the adjustment of the foregoing doping concentration level and the adjustment of the foregoing size level can be combined to improve the reliability of the foregoing connection structure 2212. That is, the size of the connection structure 2212 in the horizontal direction is smaller than that of the first central structure, and the doping concentration at the horizontal edge close to the first central structure 2211 is lower than the doping concentration of the first central structure 2211 (as shown by the foregoing Figure 6 where the doping concentration of the connection structure 2212 decreases at the edge). For example, the subsequent Figures 7 to 11 adopted Figure 7 shown connection structure can incorporate the doping concentration adjustment shown by the foregoing Figure 6 and be replaced with Figure 6 shown structure.

[0102] In some embodiments, to further isolate the isolation ability between the connection structure 2212 and the edge doping structure 222 to avoid breakdown between the connection structure 2212 and the edge doping structure 222, the foregoing avalanche pixel unit 220 can further set a plurality of isolation trenches 229 filled with insulating materials between the connection structure 2212 and the edge doping structure 222 to form an isolation trench array.

[0103] In some embodiments, the isolation trench 229 may be filled with a reflective material and / or a light-transmitting material (such as edge-filled silicon oxide and internally-filled reflective metal) to direct the light reaching the isolation trench 229 into the central doping structure 221. At this time, the isolation trench 229 may also serve as an optical scattering structure. That is, the isolation trench array is multiplexed as an optical scattering structure so that the light beam reaches the optical scattering structure and is reflected back to the avalanche pixel unit 220 by the optical scattering structure, thereby further enhancing the photon perception ability of the avalanche pixel unit 220.

[0104] In addition, if the foregoing optical scattering structure is disposed between the connection structure 2212 and the edge doping structure 222, the size limitation of the inward contraction of the foregoing connection structure 2212 can be relaxed. That is, considering that the optical scattering structure has blocked the circuit between the connection structure 2212 and the edge doping structure 222, it is not necessary to ensure that the distance d3 between the edge doping structure 222 and the connection structure 2212 in the horizontal direction is not less than the electric field path length d e , so that the edge doping structure 222 does not form a lateral inhibition electric field with the connection structure 2212 but forms a lateral inhibition electric field with the first central structure 2211.

[0105] Different from the foregoing embodiments, as Figure 11 shown, in the present application, the edge doping structure 222 may also be formed on the first surface 211. When the edge doping structure 222 is formed on the first surface 211, the edge doping structure 222 cannot form a lateral inhibition electric field with the connection structure 2212. At this time, the connection structure 2212 may not be provided, and the first central structure 2211 may be directly disposed on the second surface 212.

[0106] Continuing from the foregoing, as Figure 11 shown, when the edge doping structure 222 is formed on the first surface 211, the foregoing connection structure 2212 may also be retained to fully deploy the optical scattering structure and improve the light perception ability.

[0107] In some embodiments, considering that the foregoing second surface 212 is often connected to a metal connection layer and the actual light-incident side of the diode is generally the first surface 211, the photoelectric sensor 200 may further include a plurality of light-absorbing holes 240 disposed on the first surface 211 to form a light-absorbing hole array. The light-absorbing hole array can enhance the light-absorbing ability of the first surface 211 based on the light-absorbing characteristics of the holes.

[0108] In some embodiments, to further increase the size of the guard ring, the position of the edge doping structure 222 on the surface can be adjusted. Based on the formation requirements of the edge doping structure 222, the edge doping structure 222 can be moved to the isolation structure 230 to increase the horizontal distance d1 between the edge doping structure 222 and the first central structure 2211. That is, the edge doping structure 222 can be disposed on the isolation structure 230. At this time, the edge doping structure 222 extends across the isolation structure 230 into two adjacent avalanche pixel units and is electrically connected to the edge electrodes of each avalanche pixel unit in the two adjacent avalanche pixel units.

[0109] Specifically, Figure 9 The situation where the edge doping structure 222 is disposed on the second surface 212 and extends across two avalanche pixel units 220 is shown.

[0110] In actual processes, the traditional isolation structure 230 is generally constructed using deep trench isolation (DTI / W-DTI) technology. Metal is filled inside the formed deep trench and isolation layers are formed on both sides of the metal to improve signal isolation and light reflection isolation capabilities. The main structure can be denoted as the deep trench isolation layer 231. The metal filling in the deep trench isolation layer 231 can be denoted as the metal isolation structure 2311, and the insulating layers on both sides thereof can be denoted as the insulating sidewalls 2312. Among them, the metal isolation structure 2311 is generally constructed based on metal or other high-reflection materials, mainly as a dock metal isolation structure, and aluminum, copper, etc. can also be used as the formation materials of the metal isolation structure 2311. The insulating sidewalls 2312 are mainly used to electrically isolate the metal isolation structure 2311 from the substrate, and are generally constructed using insulating materials such as silicon oxide.

[0111] In traditional diode devices, there is generally a certain safety distance between the edge doping structure 222 and the metal isolation structure 2311 in the horizontal direction to prevent the edge electrode 224 from connecting the edge doping structure 222 and the metal isolation structure 2311 due to process errors, thereby forming an electric field.

[0112] In the case where the aforementioned edge doping structure 222 is disposed on the deep trench isolation layer 231, there can be two setting methods between the edge doping structure 222 and the deep trench isolation layer 231: ① Refer to Figure 9 the left structure in. The edge doping structure 222 can be directly connected to the metal isolation structure 2311 in the deep trench isolation layer 231. When the edge doping structure 222 is externally connected to the edge electrode 224, the edge doping structure 222 and the metal isolation structure 2311 are directly at the same potential without generating an additional potential difference.

[0113] ② Refer to Figure 9In the right-side structure, the edge doping structure 222 can be isolated from the metal isolation structure 2311 in the deep trench isolation layer 231 by the shallow trench insulation layer 232, thus directly avoiding their electrical connection. Among them, the shallow trench insulation layer 232 can be a structure formed after filling an isolation material based on the shallow trench isolation (STI) technology, which realizes the electrical isolation between the edge doping structure 222 and the shallow trench insulation layer 232.

[0114] In some embodiments, the side edges of each avalanche pixel unit 220 share the edge doping structure 222, and the isolation structure 230 is exposed at the corners of the avalanche pixel unit 220. Thus, the edge doping structures 222 are not connected to each other, which is convenient for control. In some alternative embodiments, the edge doping structures 222 can also be interconnected to completely cover the isolation structure 230.

[0115] In some embodiments, to ensure the uniform internal electric potential of the edge doping structure 222, the arrangement of the edge electrode 224 can also be optimized so that it is not arranged on different avalanche pixel units 220 based on the avalanche pixel unit 220, but is arranged on the edge doping structure 222 along the extending direction of the isolation structure 230 (as Figure 12 shown in the central avalanche pixel unit 220). Thus, the electric potential of the edge doping structure 222 can be further ensured to be the same, and at the same time, the "horizontal direction" size requirement of the edge doping structure 222 can be further reduced, and further, the size of the guard ring 226 can be increased.

[0116] In some embodiments, to reduce the space waste caused by the isolation structure 230, the pixel unit provided in this application can be further composed of multiple pixel sub-units, and each pixel sub-unit has an independent photosensitive ability and there is no such isolation structure 230 between the pixel sub-units.

[0117] To further illustrate the photoelectric sensor 200 in the foregoing case, this application also provides a cross-sectional schematic diagram thereof ( Figure 10 )

[0118] As Figure 10 shown, to form multiple pixel sub-units 227, the avalanche pixel unit 220 includes multiple central doping structures 221. Among them, the multiple central doping structures 221 form multiple pixel sub-units 227, and the central doping structures 221 correspond to the pixel sub-units 227 one by one and are arranged in the central regions of the corresponding pixel sub-units 227. Specifically, in Figure 8 the shown avalanche pixel unit 220 includes two pixel sub-units 227 and the central doping structures 221 in their central regions.

[0119] Within the avalanche pixel unit 220, its edge doping structure 222 is disposed within the pixel sub-units adjacent to the deep trench isolation layer among multiple pixel sub-units and is located on the side close to the deep trench isolation layer 231. Considering that Figure 10 both of the two pixel sub-units are adjacent to the isolation structure 230, edge doping structures 222 are provided in both of them. If the avalanche pixel unit 220 includes three or more pixel sub-units in the cross-section, the pixel sub-units away from the isolation structure 230 are not provided with edge doping structures 222.

[0120] Considering that the foregoing edge doping structure 222 is only provided in partial regions and there is no isolation structure between pixel sub-units, in order to avoid the connection of depletion layers between pixel sub-units, lightly doped structures 228 are provided in the regions of two adjacent pixel sub-units among multiple pixel sub-units that are away from the deep trench isolation layer 231. Among them, the lightly doped structure 228 has the same doping type as the edge doping structure 222, so as to isolate the depletion layers between different pixel sub-units. Only as an exemplary embodiment, the foregoing lightly doped structure 228 may be composed of boron elements.

[0121] Furthermore, considering that the pixel sub-units adjacent to the deep trench isolation layer among multiple pixel sub-units are all provided with edge doping structures 222 and their internal electric potential can be directly adjusted through the edge doping structures 222, the foregoing lightly doped structure 228 for isolating different pixel sub-units can be configured as a passive structure, that is, the lightly doped structure 228 is not electrically connected to an external electrode.

[0122] Thus, the size of the lightly doped structure 228 (such as the lightly doped structure 228 shown in Figure 10 ) within the pixel sub-units adjacent to the deep trench isolation layer can be independent of the nature of the external electrode, and thus can be configured as a narrower doping structure.

[0123] For the pixel sub-units not adjacent to the deep trench isolation layer, if their lightly doped structures can be at an appropriate electric potential without connecting to an external electrode, they do not need to be connected if not.

[0124] The foregoing Figure 10 shown multiple pixel sub-units can be combined with the foregoing Figure 9 shown avalanche pixel unit spanning. For the top view of the combined photoelectric sensor, reference can be made to the relevant description in Figure 12 .

[0125] As described above, in Figure 11 , the edge doping structure 222 and the edge electrode 224 are formed on the first surface 211. Specifically, reference can be made to the right-side situation in the foregoing Figure 5 , which will not be elaborated here.

[0126] Furthermore, as shown in Figure 11As shown, a conductive doping structure 2221 that extends into the diode substrate 210 (which can also be understood as extending toward the second surface 212) can be formed on one side of the edge doping structure 222 close to the second surface 212. The general doping type of the conductive doping structure 2221 is the same as that of the edge doping structure 222 and is configured as a lightly doped structure to increase the conductivity of the edge doping structure 222. Exemplary pixel distribution:

[0127] Based on the foregoing Figures 5 to 11 and its related content have described the internal structure of the photoelectric sensor. In the pixel composition of the photoelectric sensor, the present application is based on the foregoing Figure 9 and Figure 10 to illustrate the specific situation in the top-down view when the avalanche pixel units with multiple pixel sub-units share the edge doping structure ( Figure 12 ).

[0128] As Figure 12 shown, the side edges of each avalanche pixel unit 220 share the edge doping structure 222, and the isolation structure 230 is exposed at the corners of the avalanche pixel unit 220. Thus, the edge doping structures 222 are not connected to each other, facilitating control. In some alternative embodiments, the edge doping structures 222 can also be interconnected to completely cover the isolation structure 230.

[0129] In some embodiments, to ensure the uniform internal electric potential of the edge doping structure 222, the layout of the edge electrode 224 can also be optimized so that it is not arranged on different avalanche pixel units 220 based on the avalanche pixel unit 220, but is arranged on the edge doping structure 222 along the extension direction of the isolation structure 230 (as shown in the avalanche pixel unit 220 in the Figure 12 center). Thus, it can further ensure that the electric potential of the edge doping structure 222 is the same, and at the same time, it can further reduce the "horizontal direction" size requirement of the edge doping structure 222, thereby further increasing the size of the guard ring 226.

[0130] Furthermore, as Figure 12 shown, in the top-down view, an array arrangement of 4 pixel sub-units 227 can form an avalanche pixel unit 220. Each pixel sub-unit 227 has a central doping structure 221 inside, the edge doping structure 222 is arranged on one side of each pixel sub-unit 227 close to the isolation structure 230, and a passive lightly doped structure 228 is arranged between the pixel sub-units 227.

[0131] Thus, based on the foregoing Figure 12The photoelectric sensor shown reduces the space occupied by the isolation structure by constructing a pixel unit by packing multiple pixel units. At the same time, the pixel sub-units are isolated and separated by a passive lightly doped structure, so that the size of each lightly doped structure does not need to consider the requirements of electrode connection, and thus the size requirement can be further reduced.

[0132] In the top-down view of the photoelectric sensor, the present application further finds that the distribution of the edge doping structure in the horizontal plane can be further optimized to increase the size of the guard ring.

[0133] To further illustrate this process, the present application takes the horizontal plane distribution of the edge doping structure of a conventional photoelectric sensor as an example for illustration. That is, the present application also provides a top-down schematic diagram of a photoelectric sensor ( Figure 5 shown). Figure 13 ). Among them, for the convenience of illustrating the arrangement in a single diode, only one avalanche pixel unit is shown in the subsequent top-down view.

[0134] As Figure 13 shown, when the safety distance from the isolation structure 230 is not considered, the edge doping structure 222 is generally arranged with equal thickness along the inside of the isolation structure 230. For the isolation structure 230 that usually isolates a rectangular or square pixel space (also denoted as the square / rectangular pixel edge), this may result in different shortest distances from each point in the pixel edge (i.e., inside the isolation structure) of the avalanche pixel unit to the central doping structure.

[0135] Taking Figure 13 the positive pixel space (the inner wall of the isolation structure 230 forms a square) and the circular central doping structure 221 shown as an example, the shortest distance from the midpoint of the straight edge of the rectangle (formed by the inner wall of the isolation structure 230) to the central doping structure 221 can be the minimum value D of the shortest distances from the pixel edge of the avalanche pixel unit to the central doping structure emin , and the shortest distance from the right angle of the rectangle to the central doping structure 221 can be the maximum value D of the shortest distances from the pixel edge of the avalanche pixel unit to the central doping structure emax .

[0136] If the edge doping structure 222 is arranged with equal thickness along the inside of the isolation structure 230 based on the traditional design idea, it will result in a smaller guard ring size at the aforementioned D emin location, making it easier to be broken down, while the edge doping structure 222 / guard ring at the aforementioned D emax location cannot share the breakdown risk for it.

[0137] Therefore, considering the unreasonableness of the aforementioned horizontal plane distribution, the present application optimizes this distribution situation and provides Figures 14 to 17 multiple top-down structural schematic diagrams shown.

[0138] As described above, considering that the guard ring size at D emin is small and the guard ring at D emax cannot share the breakdown risk for it, when doping the edge doping structure in this application, based on this situation, the edge doping structure located at D emin can be transferred towards D emax to increase the size of the guard ring at D emin .

[0139] Thus, the width D gr of the guard ring satisfies the following relationship: D emin - W avg <D gr <D emax - W avg , where W avg is the average size of the edge doping structure in the horizontal direction.

[0140] To further describe the difference between this distribution and the traditional distribution, this application Figure 11 provides a photoelectric sensor optimized based on the above logic.

[0141] As Figure 14 shown, the edge doping structure 222 transfers from D emin and its vicinity towards D emax and accumulates at the right angle of the rectangle. In Figure 14 the distribution of the edge doping structure in Figure 13 is also shown in dashed lines. Based on Figure 14 the actual distribution of the edge doping structure 222 in emin and the shape of the dashed line (which also reflects the average size of the edge doping structure in the horizontal direction), it can be clearly seen that the edge doping structure 222 transfers from D emax and accumulates at the right angle of the rectangle to make the width D gr of the guard ring meet the aforementioned requirements.

[0142] Furthermore, considering the breakdown probability of the guard ring at each point, as a preferred embodiment, the width D gr of the guard ring is constant to form an annular edge surrounding the central doping structure, facilitating the edge doping structure 222.

[0143] Based on Figure 14 the situation shown, this application also provides a schematic diagram of the guard ring forming an annular structure ( Figure 15 ). As Figure 15 shown, in Figure 15The shape of the guard ring can be directly presented as a circular ring concentric with the central doping structure, and the edge doping structure 222 is filled between the circular ring and the pixel edge.

[0144] In addition, as a preferred embodiment, Figure 15 in, the guard ring can directly extend to the pixel edge within the tolerance range to make D gr ≈D emin (or D gr =D emin ). Among them, generally, some edge doping structures need to be left at the edge to connect the edge doping structures at each right angle (it can also be not left considering the subsequent situation of directly setting electrodes at the right angles).

[0145] To illustrate the shape of the guard ring in other forms of the central doping structure, this application Figure 16 also shows the shape of the guard ring when the central doping structure is presented as a square.

[0146] As Figure 16 shown, based on the square central doping structure, its guard ring can be presented as a rounded rectangle. Among them, the straight sides of the rounded rectangle are equidistant from the straight sides of the square, and the corners of the rounded rectangle are presented as quarter circles with the right angles of the square as the center and the distance between them as the radius. Thus, the distance from any point in the rounded rectangle to the square is equal.

[0147] Based on the situation that the shortest distance D e from the pixel edge of the aforementioned avalanche pixel unit to the central doping structure is not always a fixed value, the edge doping structure often accumulates at D emax . Thus, the area of the doping structure here is larger and it is easier to meet the size requirements during electrode formation. Thus, based on the situation that D e is not always a fixed value, the pixel edge is parallel to the annular edge at D emin , and is not parallel to the annular edge at D emax to form an edge bend, and the edge electrode is arranged between the edge bend and the annular edge.

[0148] Specifically, the aforementioned pixel edge being parallel to the annular edge at D emin can include parallelism in the tangential direction (such as Figure 11 the parallelism between the tangential direction at the midpoint of the straight side of the rectangle in / 12 and the tangential direction of the circular central doping structure) and actual parallelism (such as Figure 16 in, the parallelism between the straight side of the rectangular part and the straight side of the rectangular central doping structure). Then, the corresponding aforementioned edge bend often forms between the parallel structures. As Figures 14 to 16 shown in the structures, edge bend structures are formed at the right angles. Then, the edge electrode can be arranged here.

[0149] Combined with the foregoingFigures 14 to 16 It can be seen that the pixel space is configured as a rectangle, and the edges are bent into rectangular right-angle regions. The minimum value D among the shortest distances from the pixel edges of the avalanche pixel units to the central doping structure emin is the shortest distance from the midpoint of the right-angle side to the central doping structure. The maximum value D among the shortest distances from the pixel edges of the avalanche pixel units to the central doping structure emax is the shortest distance from the rectangular right angle to the central doping structure.

[0150] In addition to the foregoing Figures 14 to 16 shown cases, the pixel space can also be configured in other forms. Generally, to achieve the densest arrangement of the pixel space, its form can be presented as a regular hexagon.

[0151] In addition, in some embodiments, the shortest distance D from the pixel edge of the avalanche pixel unit to the central doping structure e can also be a constant value. At this time, the pixel edge of the avalanche pixel unit and the central doping structure generally present as concentric circles (it can also be presented as a concentric rounded polygon). At this time, the foregoing equal-thickness distribution can be directly adopted so that the width D of the protection ring gr =D e -W avg . Specifically, reference can be made to the Figure 17 shown cases.

[0152] However, in practice, considering that when the pixel edge is circular, the densest arrangement is often not achievable, which may lead to waste of space, it can also be converted into a square or a regular hexagon based on the foregoing layout requirements.

[0153] In summary, for the adjustment of the edge doping structure distribution, by ensuring that the shortest distance from any point on the side of the central doping structure close to the edge doping structure to the central doping structure is significantly increased, the optimized distribution (or optimal distribution) of the edge doping structure is achieved. Exemplary electronic device:

[0154] Based on the photoelectric sensor provided in the foregoing content, an embodiment of this specification provides a photoelectric detection device, which includes any one of the above photoelectric sensors. The photoelectric detection device obtains relevant information by sensing the electrical signal generated corresponding to the received optical signal of the photoelectric sensor. For example, the photoelectric detection device may include a transmitting component, a receiving component, and a processing module. The transmitting component emits a sensing optical signal into the measurement scene. The receiving component includes a photoelectric sensor to sense the sensing optical signal reflected back by an external object and output a corresponding electrical signal. The processing module processes and analyzes the output electrical signal to obtain the distance information of the external object. The photoelectric detection device may include a plurality of photoelectric sensors arranged in an array. The photoelectric detection device may be a sensing chip or a sensing circuit. For example, the photoelectric sensing device may be a proximity sensor, a Time of Flight (TOF) sensor, a lidar, etc.

[0155] On this basis, an embodiment of this specification provides an electronic device, which includes the above photoelectric detection device. The electronic device is used to perform corresponding functions according to the relevant information obtained by sensing the electrical signal of the photoelectric detection device. The corresponding functions include, but are not limited to, unlocking after identifying the user's identity, making payments, starting a preset application program, avoiding obstacles, and judging the user's mood and health status using deep learning technology after identifying the user's facial expression, any one or more of them.

[0156] The electronic device may be a suitable type of electronic product such as a consumer electronic product, a home electronic product, a smart mobile tool, or a financial terminal product. Among them, the consumer electronic product may be a mobile phone, a tablet computer, a laptop computer, a desktop monitor, an all-in-one computer, etc. The home electronic product may be a smart door lock, a TV, a refrigerator, a wearable device, etc. The smart mobile tool may be a car, a robot, a self-driving delivery cart, etc. The financial terminal product may be an automated teller machine, a terminal for self-service business handling, etc.

[0157] The above are only specific embodiments of this specification, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed in this specification can easily think of changes or substitutions, which should all be covered within the protection scope of this specification. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. An optoelectronic sensor, characterized in that, Comprising: A diode substrate having opposite first and second surfaces in the vertical direction; A plurality of avalanche pixel units disposed within the diode substrate and isolation structures for isolating the avalanche pixel units; The avalanche pixel unit includes a central electrode, an edge electrode, a central doping structure, and an edge doping structure. Wherein, the edge doping structure is formed on the first surface or the second surface and is electrically connected to the corresponding edge electrode, and the central electrode is disposed on the second surface; The central doping structure includes a first central structure and a connection structure. Wherein, the doping type of the first central structure is different from that of the edge doping structure and is far from the surface where the edge doping structure is located, and the connection structure is used to electrically connect the central electrode and the first central structure; The first central structure is used to form an avalanche region in the vertical direction and form a lateral suppression electric field with the edge doping structure. The first central structure and the edge doping structure are separated both horizontally and vertically, so that the electric field path length of the lateral suppression electric field is greater than the projection distance of the first central structure and the edge doping structure in the vertical direction.

2. The optoelectronic sensor according to claim 1, characterized in that, The connection structure is configured to connect the doping structures of the first central structure and the central electrode, and the doping type of the connection structure is the same as that of the first central structure; The edge doping structure extends from the second surface into the diode substrate, and the extension depth of the edge doping structure in the vertical direction is less than the extension depth of the connection structure in the vertical direction; The size of the connection structure in the horizontal direction is less than that of the first central structure, and / or the doping concentration of the connection structure near the horizontal edge of the first central structure is lower than the doping concentration of the first central structure.

3. The optoelectronic sensor according to claim 2, characterized in that, The doping concentration of the connection structure decreases in the horizontal direction along the direction away from the central electrode; and / or The doping concentration of the connection structure increases in the vertical direction along the direction towards the first central structure.

4. The optoelectronic sensor according to claim 2, characterized in that, The photoelectric sensor further includes an isolation trench array extending from the first surface into the diode substrate and located between the edge doping structure and the connection structure, and the isolation trench array is multiplexed as an optical scattering structure.

5. The optoelectronic sensor according to claim 2, characterized in that, The edge doping structure extends across the isolation structure into two adjacent avalanche pixel units and is electrically connected to the edge electrodes of each avalanche pixel unit in the two adjacent avalanche pixel units; One side of the edge doping structure far from the second surface is isolated from one side of the deep trench isolation layer in the isolation structure close to the second surface by a shallow trench insulating layer, or one side of the edge doping structure far from the second surface is electrically connected and at the same potential with the metal isolation structure in the deep trench isolation layer in the isolation structure.

6. The optoelectronic sensor according to claim 2, characterized in that, A plurality of central doping structures are included within the avalanche pixel unit. Wherein, the plurality of central doping structures form a plurality of pixel sub-units, and the central doping structure corresponds to each pixel sub-unit one by one and is disposed in the central region of the corresponding pixel sub-unit; The edge doping structure is disposed in the pixel sub-units adjacent to the isolation structure among the plurality of pixel sub-units and on the side close to the isolation structure; A lightly doped structure is disposed in the regions of two adjacent pixel sub-units among the plurality of pixel sub-units that are far from the isolation structure, wherein the lightly doped structure has the same doping type as the edge doping structure; the lightly doped structure in the pixel sub-units adjacent to the isolation structure among the plurality of pixel sub-units is not electrically connected to the external electrode.

7. The optoelectronic sensor according to claim 2, wherein When the minimum value D of the shortest distance from the pixel edge of the avalanche pixel unit to the central doping structure emin is not equal to the maximum value D emax the width D of the guard ring gr satisfies the following relationship: D emin -W avg <D gr <D emax -W avg where W avg is the average size of the edge doping structure in the horizontal direction.

8. The optoelectronic sensor according to claim 1, characterized in that, The edge doping structure extends from the first surface into the diode substrate, and the edge electrode is disposed on the first surface.

9. The optoelectronic sensor according to claim 8, characterized in that The photoelectric sensor further includes a conductive doping structure that extends from the side of the edge doping structure close to the first surface into the diode substrate.

10. The optoelectronic sensor according to claim 1, characterized in that, The light-incident side of the diode substrate has an array of light-absorbing holes.

11. An optoelectronic detection device, characterized in that, Comprising the photoelectric sensor according to any one of claims 1 to 10, the photoelectric detection device obtains relevant information by sensing the electrical signal corresponding to the received optical signal of the photoelectric sensor.

12. An electronic device, characterized in that, Comprising the photoelectric detection device according to claim 11, the electronic device is configured to perform corresponding functions according to the relevant information obtained by sensing the electrical signal of the photoelectric detection device.

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