CN115954405B

CN115954405B - Single photon avalanche diode device, detection circuit, laser radar, preparation method, driving method and ranging method

Info

Publication number: CN115954405B
Application number: CN202310239491.4A
Authority: CN
Inventors: 郭雪凯; 赵彦; 王天洋
Original assignee: Suzhou Zhiguang Xinke Technology Co ltd
Current assignee: Suzhou Zhiguang Xinke Technology Co ltd
Priority date: 2023-03-14
Filing date: 2023-03-14
Publication date: 2023-06-16
Anticipated expiration: 2043-03-14
Also published as: CN115954405A

Abstract

The application relates to a single photon avalanche diode device, a detection circuit, a laser radar, a preparation method, a driving method and a ranging method. A single photon avalanche diode device comprising: a substrate; the substrate includes a back surface and a front surface opposite the back surface; an epitaxial layer disposed on the front surface; the P-type doped region, the PN combination doped region and the first isolation region are arranged on the top of the epitaxial layer; wherein, anode contact is arranged in the P-type doped region; the PN combination doped region comprises a first sub PN combination doped region and a second sub PN combination doped region, and the first isolation region is positioned between the first sub PN combination doped region and the second sub PN combination doped region; the first sub PN junction doped region and the second sub PN junction doped region are both provided with cathode contacts. According to the single photon avalanche diode device, the subarea measurement of the sub-pixel device is realized, so that the linearity and the accuracy of ranging can be improved.

Description

Single photon avalanche diode device, detection circuit, laser radar, preparation method, driving method and ranging method

Technical Field

The application relates to the technical field of semiconductors, in particular to a single photon avalanche diode device, a detection circuit, a laser radar, a preparation method, a driving method and a ranging method.

Background

The laser radar is a radar system for detecting the characteristic quantities of the target such as the distance, the speed and the like by emitting laser beams, and plays important roles of road edge detection, obstacle identification, real-time positioning and drawing and the like in automatic driving. Lidar comprises a photodetector, wherein one photodetector is a single photon avalanche diode (Single Photon Avalanche Diode, SPAD), which is an avalanche diode operating in geiger mode. Single photons generate carriers in the SPAD neutral body region or depletion region, move to the avalanche region of high electric field through diffusion or drift, and trigger avalanche current due to impact ionization. Once the avalanche is triggered, it is quenched, either actively or passively, and after a certain time it is returned to the reset state again in order to detect the next photon event. SPADs are unable to detect photons during the period from quenching to resetting.

The limitation of SPAD dead time makes only one pulse output in one laser emission pulse. Along with the shortening of the distance and the increase of the light intensity, the time of each pulse output is more and more close to the front edge of the emitted light pulse until the time is consistent with the front edge of the emitted light pulse, and at the moment, the density of the photon detection output histogram is not changed along with the change of the light intensity, so that the accurate signal light return time cannot be obtained according to the histogram, and the ranging linearity and the accuracy of the laser radar are further reduced.

Disclosure of Invention

The embodiment of the application provides a single photon avalanche diode device, a detection circuit, a laser radar, a preparation method, a driving method and a ranging method, which can improve the ranging linearity and the ranging precision.

In one aspect, the present application provides a single photon avalanche diode device comprising: a substrate; the substrate includes a back surface and a front surface opposite the back surface; an epitaxial layer disposed on the front surface; the P-type doped region, the PN combination doped region and the first isolation region are arranged on the top of the epitaxial layer; wherein, anode contact is arranged in the P-type doped region; the PN combination doped region comprises a first sub PN combination doped region and a second sub PN combination doped region, and the first isolation region is positioned between the first sub PN combination doped region and the second sub PN combination doped region; the first sub PN junction doped region and the second sub PN junction doped region are both provided with cathode contacts.

Optionally, the two sub-PN junction doped regions are a first sub-PN junction doped region and a second sub-PN junction doped region, respectively; each sub PN junction doped region comprises a sub P type doped region and a sub N type doped region positioned below the sub P type doped region.

Optionally, the first isolation region is an STI trench formed using a shallow trench isolation STI process.

Optionally, the single photon avalanche diode device further comprises:

a second isolation region disposed around the epitaxial layer; the second isolation region is a DTI trench formed using a deep trench isolation DTI process.

Optionally, the cathode contact of the first sub-PN junction doped region is respectively and/or and connected to the component via a first inverter; the cathode contact of the second sub-PN junction doped region is connected to the respective AND/OR component and to the component through a second inverter.

Optionally, the anode contact is coupled to a first supply voltage terminal; the cathode contact 160 of the first sub-PN junction doped region 131 is coupled to a second supply voltage terminal through a first resistor 470; the cathode contact 160 of the second sub-PN junction doped region 132 is coupled to a second supply voltage terminal through a second resistor 480.

In another aspect, the present application provides a detection circuit of a single photon avalanche diode device, which is applied to the single photon avalanche diode device, and the detection circuit includes: the first circuit connects the cathode contact of the first sub PN junction doped region through a first inverter and or component, and connects the cathode contact of the second sub PN junction doped region through a second inverter and or component; and the second circuit is used for connecting the cathode contact of the first sub PN junction doped region with the component through the first inverter and connecting the cathode contact of the second sub PN junction doped region with the component through the second inverter.

In another aspect, the present application provides a lidar comprising: the transmitting unit is used for providing a transmitting light beam, and the transmitting light beam is reflected by the target object to form an echo light beam; and the receiving unit is used for receiving the echo light beam and comprises the single photon avalanche diode device.

In another aspect, the present application provides a method for fabricating a single photon avalanche diode device, comprising:

providing a substrate; the substrate includes a back surface and a front surface opposite the back surface; forming an epitaxial layer on the front surface of the substrate; forming a first isolation region on an end surface of the epitaxial layer away from the substrate using an STI process; forming a P-type doped region and a PN combination doped region on the end surface of the epitaxial layer far away from the substrate; the PN combination doped region comprises a first sub PN combination doped region and a second sub PN combination doped region, and the first isolation region is positioned between the first sub PN combination doped region and the second sub PN combination doped region; forming a second isolation region extending from the front surface of the substrate to an end surface of the epitaxial layer away from the substrate using a DTI process; forming an anode contact in the P-type doped region; a cathode contact is formed within each sub-PN junction doped region.

In another aspect, the present application provides a driving method of a single photon avalanche diode device, which is applied to the single photon avalanche diode device, and the method includes: coupling an anode contact to a first supply voltage terminal; coupling the cathode contact of the first sub PN junction doped region and the cathode contact of the second sub PN junction doped region to a second power supply voltage terminal through a quenching resistor, respectively; outputting a first driving voltage to a first power supply voltage terminal; outputting the second driving voltage to the second power voltage terminal.

On the other hand, the application provides a ranging method, which is applied to the detection circuit of the single photon avalanche diode device, and comprises the following steps: transmitting an optical pulse to a target object, and detecting a first detection signal output by the first circuit and a second detection signal output by the second circuit; determining first detection photon data according to the first detection signal; the first detected photon data characterizes the number of photons detected by the first circuit in each of a plurality of preset time intervals; determining second detection photon data according to the second detection signal; the second detected photon data comprises the number of photons detected by the second circuit in each preset time interval; determining first distance information of the target object based on the first detected photon data; determining second distance information of the target object based on the second detected photon data; determining the first distance information as target distance information under the condition that the first distance information and/or the second distance information meet a first preset condition; and determining the second distance information as target distance information under the condition that the first distance information and/or the second distance information meet the second preset condition.

Optionally, each preset time interval corresponds to a preset photon return time, and determining the first distance information of the target object based on the first detected photon data includes: and determining first distance information of the target object based on the first detection photon data, the preset photon return time corresponding to the preset time interval where each first detection photon data is located and the precision of the time digital conversion module.

In another aspect, the present application provides a ranging apparatus, which is applied to the detection circuit of a single photon avalanche diode device, and the apparatus includes:

the transmitting module is used for transmitting the light pulse to the target object and detecting a first detection signal output by the first circuit and a second detection signal output by the second circuit;

the first determining module is used for determining first detection photon data according to the first detection signal; the first detected photon data characterizes the number of photons detected by the first circuit in each of a plurality of preset time intervals;

the second determining module is used for determining second detection photon data according to the second detection signal; the second detected photon data comprises the number of photons detected by the second circuit in each preset time interval;

a third determining module for determining first distance information of the target object based on the first detection photon data;

a fourth determining module for determining second distance information of the target object based on the second detected photon data;

the first distance module is used for determining the first distance information as target distance information under the condition that the first distance information and/or the second distance information meet a first preset condition;

And the second distance module is used for determining the second distance information as target distance information under the condition that the first distance information and/or the second distance information meet a second preset condition.

Optionally, each preset time interval corresponds to a preset photon return time, and the third determining module is configured to: and determining first distance information of the target object based on the first detection photon data, the preset photon return time corresponding to the preset time interval where each first detection photon data is located and the precision of the time digital conversion module.

The single photon avalanche diode device, the detection circuit, the laser radar, the preparation method, the driving method and the ranging method provided by the embodiment of the application have the following beneficial effects:

(1) By isolating the single photon avalanche diode pixel device into a plurality of sub-pixel devices, each sub-pixel can be ensured to be independently quenched and reset under the cooperation of a pixel quenching circuit, and the working state of surrounding sub-pixels is not influenced, so that the zoned photon detection is realized;

(2) Through the logic and relation among the sub-pixels, the response of the single photon avalanche diode to strong light during short-distance measurement is reduced, and therefore the situation of histogram saturation is solved. When the reflected light intensity of a measured object at a long distance is insufficient, the responsivity of the single photon avalanche diode to weak light is increased through the logic or relation among the sub-pixels, so that the normal distance measuring function is recovered;

(3) By adding the first isolation regions, the PN combination doped regions are divided into a plurality of sub PN combination doped regions by the plurality of first isolation regions, or the positions of the first isolation regions are adjusted, so that the equivalent photon detection efficiency with different values can be flexibly realized;

(4) The first distance information is obtained by obtaining the detection signal output by the OR gate, the second distance information is obtained by obtaining the detection signal output by the AND gate, then the first distance information and the second distance information are combined to conduct distance measurement, the distance measurement result is flexibly adopted under the conditions of long distance and short distance, the problem of low short distance measurement precision can be avoided, meanwhile, the problem of inaccurate long distance measurement is avoided, and therefore the short distance measurement precision, linearity and long distance measurement accuracy are guaranteed.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a single photon avalanche diode device according to an embodiment of the present application;

fig. 2 is a schematic structural diagram of a single photon avalanche diode device according to an embodiment of the present application;

fig. 3 is a top view of a single photon avalanche diode device provided in an embodiment of the present application;

fig. 4 is a schematic circuit structure of a single photon avalanche diode device according to an embodiment of the present application;

fig. 5 is a schematic flow chart of a method for manufacturing a single photon avalanche diode device according to an embodiment of the present application;

fig. 6 is a schematic flow chart of a driving method of a single photon avalanche diode device according to an embodiment of the present application;

fig. 7 is a schematic flow chart of a ranging method according to an embodiment of the present application;

FIG. 8 (a) is a schematic waveform diagram of an emitted light pulse according to an embodiment of the present application;

fig. 8 (b) is a schematic waveform diagram of cathode voltages of two sub-pixel devices of a single photon avalanche diode device according to an embodiment of the present application;

fig. 8 (c) is a schematic waveform diagram of output signals of two sub-pixel devices of a single photon avalanche diode device according to an embodiment of the present application;

fig. 8 (d) is a schematic waveform diagram of output signals of and/or components of a single photon avalanche diode device according to an embodiment of the present application;

Fig. 8 (e) is a schematic diagram of an output histogram of a single photon avalanche diode device provided in an embodiment of the present application;

FIG. 9 (a) is a schematic diagram of the relationship between the distance and the reflected light intensity of a single photon avalanche diode device according to an embodiment of the present application;

fig. 9 (b) and 9 (c) are schematic diagrams of output histograms of a plurality of detection distances of a single photon avalanche diode device according to an embodiment of the present application;

fig. 10 is a schematic diagram of ranging linearity of a ranging method according to an embodiment of the present disclosure;

fig. 11 is a schematic structural diagram of a ranging device according to an embodiment of the present disclosure;

an epitaxial layer-110; p-type doped region-120; PN junction doped region-130; a first sub-PN junction doped region 131; a second sub-PN junction doped region-132; a first isolation region-140; anode contact-150; cathode contact-160; a second isolation region-170; a first sub-pixel device-410; a second sub-pixel device-420; a first inverter-430; a second inverter-440; or component-450; and component-460; a first resistor-470; second resistor-480.

Detailed Description

The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present application based on the embodiments herein.

It should be noted that the terms "first," "second," and the like in the description and claims of the present application and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that embodiments of the present application described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or server that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed or inherent to such process, method, article, or apparatus, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a single photon avalanche diode device according to an embodiment of the present application. The single photon avalanche diode device illustrated according to fig. 1 includes a substrate, an epitaxial layer 110, a p-type doped region 120, a pn junction doped region 130, a first isolation region 140, an anode contact 150, and a cathode contact 160.

In an alternative embodiment, the substrate includes a back surface and a front surface opposite the back surface, the substrate not being illustrated in fig. 1 for ease of illustration. An epitaxial layer 110 is disposed on the front surface of the substrate.

The P-type doped region 120, the PN junction doped region 130, and the first isolation region 140 are disposed on top of the epitaxial layer 110. Alternatively, the P-type doped region 120 may be a P-well doped region.

The PN junction doped region 130 includes a first sub-PN junction doped region 131 and a second sub-PN junction doped region 132, and the first isolation region 140 is located between the first sub-PN junction doped region 131 and the second sub-PN junction doped region 132. The first sub-PN junction doped region 131 and the second sub-PN junction doped region 132 may be sub-diode regions of a single photon avalanche diode device. Each sub PN junction doped region comprises a sub P type doped region and a sub N type doped region positioned below the sub P type doped region.

An anode contact 150 is disposed within the P-type doped region 120, and a cathode contact 160 is disposed in both the first sub-PN junction doped region 131 and the second sub-PN junction doped region 132. Specifically, separate cathode contacts 160 are provided in the first sub-PN junction doped region 131 and in the second sub-PN junction doped region 132, and the first sub-PN junction doped region 131 and the second sub-PN junction doped region 132 share the anode contact 150.

Alternatively, the first isolation region 140 is an STI trench formed using a shallow trench isolation STI process.

Optionally, each sub-pixel device of the single photon avalanche diode device provided in the embodiments of the present application may operate in geiger mode, and when photons are collected by the PN junction and avalanche occurs, the sub-pixel may be considered to complete one photon detection. The detection efficiency is positively correlated with the area of the sub-pixel. The areas of the first sub-PN junction doped region 131 and the second sub-PN junction doped region 132 can be flexibly changed by changing the position of the first isolation region 140, thereby changing the photon detection efficiency of the two sub-pixels. In an alternative embodiment, the sum of the photon detection efficiencies of the first sub-pixel device and the second sub-pixel device is fixed, for example, may be fixed to 20%, in this embodiment, the photon detection efficiencies of the two sub-pixel devices may be adjusted to 10% and 10%, 12% and 8%, 15% and 5%, and so on by adjusting the position of the first isolation region 140. It should be noted that the application is not limited to photon detection efficiency of the sub-pixel device, and in other alternative embodiments, the photon detection efficiency of each of the sub-pixel devices and the sum of the photon detection efficiencies may be other alternative values. According to the embodiment of the application, the single photon avalanche diode pixel device is isolated into the plurality of sub-pixel devices, so that each sub-pixel can be independently quenched and reset under the cooperation of the pixel quenching circuit, the working state of surrounding sub-pixels is not influenced, and the regional photon detection is realized.

Referring to fig. 2, fig. 2 is a schematic structural diagram of a single photon avalanche diode device according to an embodiment of the present application. The single photon avalanche diode device illustrated in accordance with fig. 2 includes a substrate, an epitaxial layer 110, a p-type doped region 120, a pn junction doped region 130, a first isolation region 140, an anode contact 150, a cathode contact 160, and a second isolation region 170.

In an alternative embodiment, as illustrated in fig. 2, the single photon avalanche diode device further includes:

a second isolation region 170 disposed around epitaxial layer 110; the second isolation region 170 is a DTI trench formed using a deep trench isolation DTI process. The second isolation region 170 is used to isolate the single photon avalanche diode pixel device illustrated in fig. 2 from other semiconductor structures.

Referring to fig. 3, fig. 3 is a top view of a single photon avalanche diode device according to an embodiment of the present application.

As illustrated in fig. 3, the P-type doped region 120 is located at the edge of the single photon avalanche diode pixel device. The anode contact 150 is distributed in the P-type doped region 120.

The first isolation region 140 separates the PN junction doped region 130 into two sub-PN junction doped regions, a first sub-PN junction doped region 131 and a second sub-PN junction doped region 132, respectively. The two cathode contacts 160 are uniformly distributed in the two sub-PN doped regions in a ring shape, respectively. In the embodiment of the present application, the PN junction doped region 130 is divided into two sub-PN junction doped regions by providing the first isolation region 140, so that the single photon avalanche diode pixel device is divided into two sub-pixel devices.

The second isolation region 170 is disposed around the epitaxial layer 110.

In an alternative embodiment, the number of the first isolation regions 140 may include a plurality, and in particular, the structure of a single photon avalanche diode provided in the embodiment of the present application is not limited to the structures illustrated in fig. 1, 2 and 3, and the number of the sub-PN junction doped regions may be three or more, and the single photon avalanche diode pixel device may be divided into three or more sub-pixel devices by the first isolation regions 140. The single photon avalanche diode device may further be provided with a plurality of first isolation regions on the basis of the structures shown in fig. 1, 2 and 3, keeping the total area of the PN junction doped region 130 unchanged, and the plurality of first isolation regions may divide the PN junction doped region into a plurality of sub-PN junction doped regions to form a plurality of sub-pixel devices. In this embodiment, the sum of photon detection efficiencies of the plurality of sub-pixel devices of the single photon avalanche diode device is fixed, for example, may be fixed to 20%, and the photon detection efficiency of different values of each sub-pixel device may be achieved by adjusting the area of each sub-PN junction doped region in different sub-PN junction doped regions. Alternatively, in an embodiment in which the number of sub-PN junction doped regions is 3 in total, the photon detection efficiency of the 3 sub-PN junction doped regions from the outside to the inside may be 5%,5%,10%, respectively. It should be noted that the number of sub-pixel devices and the photon detection efficiency of each sub-pixel device are not limited in the embodiments of the present application, and in other alternative embodiments, the sub-pixel devices may be other numbers, and the photon detection efficiency of each sub-pixel device may be other values.

Referring to fig. 4, fig. 4 is a schematic circuit structure of a single photon avalanche diode device according to an embodiment of the present application.

For ease of illustration, the cathode of the first sub-pixel device 410 shown in fig. 4 characterizes the cathode contact 160 of the first sub-PN junction doped region 131 as set forth above, and the anode of the first sub-pixel device 410 characterizes the anode contact 150 of the first sub-PN junction doped region 131 as set forth above; the cathode of the second sub-pixel device 420 shown in fig. 4 characterizes the cathode contact 160 of the second sub-PN junction doped region 132 as set forth above, and the anode of the second sub-pixel device 420 characterizes the anode contact 150 of the second sub-PN junction doped region 132 as described above.

As illustrated in fig. 4, the circuit includes a quenching circuit. In the quenching circuit, the anode of the first sub-pixel device 410 and the anode of the second sub-pixel device 420 are coupled to the first power supply voltage terminal; the cathode of the first sub-pixel device 410 and the cathode of the second sub-pixel device 420 are coupled to a second supply voltage terminal through a first resistor 470 and a second resistor 480, respectively. The first resistor 470 and the second resistor 480 may be quench resistors. Alternatively, the quenching circuit may be an active quenching circuit or a passive quenching circuit.

As illustrated in fig. 4, the circuit includes a detection circuit. In the detection circuit, the cathode of the first sub-pixel device 410 is connected to the or component 450 and to the component 460 via the first inverter 430, respectively. The cathode of the second sub-pixel device 420 is connected to the OR component 450 and to the component 460, respectively, through a second inverter 440. Or component 450 is used to output a first detection signal and component 460 is used to output a second detection signal, the first detection signal and the second detection signal being used for target detection. It should be appreciated that the first detection signal output by the or component 450 is at a high level when either one of the first sub-pixel device 410 and the second sub-pixel device 420 outputs a high level, and the equivalent first photon detection efficiency is the sum of the photon detection efficiencies of the first sub-pixel device and the second sub-pixel device; the second detection signal output from the and component 460 is high if and only if both the first sub-pixel device 410 and the second sub-pixel device 420 output a high level; the equivalent second photon detection efficiency is the product of the photon detection efficiencies of the first and second sub-pixel devices. For example, if the first sub-pixel device 410 outputs a low level and the second sub-pixel device 420 outputs a high level, the or component 450 outputs a high level and the and component 460 outputs a low level.

Alternatively, the areas of the first sub-PN junction doped region 131 and the second sub-PN junction doped region 132 may be determined according to the position information of the first isolation region 140, thereby determining the photon detection efficiency of the two sub-pixels; and determining the sum of the photon detection efficiencies of the first sub-pixel device and the second sub-pixel device as a first photon detection efficiency, and determining the product of the photon detection efficiencies of the first sub-pixel device and the second sub-pixel device as a second photon detection efficiency.

In an alternative embodiment, the sum of the photon detection efficiencies of the first sub-pixel device and the second sub-pixel device is fixed, for example, may be fixed to 20%, in this embodiment, the photon detection efficiencies of the first sub-pixel device and the second sub-pixel device may be determined according to the position of the first isolation region 140, for example, 10% and 10%, 12% and 8% or 15% and 5%, respectively, and so on.

It should be noted that the position information of the first isolation region 140 and the photon detection efficiency of the sub-pixel device are not limited in this application, and in other alternative embodiments, the position of the first isolation region 140 may be any position, and the sum of the photon detection efficiencies of the sub-pixel devices may be other alternative values.

Accordingly, the present application provides a lidar comprising: and the emission unit is used for providing an emission light beam, and the emission light beam is reflected by the target object to form an echo light beam. And the receiving unit is used for receiving the echo light beam and comprises the single photon avalanche diode device.

Accordingly, the present application provides a method for fabricating a single photon avalanche diode device, which is described in detail below in conjunction with fig. 5.

Referring to fig. 5, fig. 5 is a schematic flow chart of a method for manufacturing a single photon avalanche diode device according to an embodiment of the present application, including:

step S501: a substrate is provided.

Alternatively, the substrate may include a back surface and a front surface opposite the back surface.

Step S502: an epitaxial layer 110 is formed on the front surface of the substrate.

Step S503: the STI process is used to form a first isolation region 140 on the end of the epitaxial layer 110 remote from the substrate.

Step S504: p-type doped region 120, PN junction doped region 130 are formed on the end of epitaxial layer 110 remote from the substrate.

Alternatively, the PN junction doped region 130 may include two sub-PN junction doped regions, which are the first sub-PN junction doped region 131 and the second sub-PN junction doped region 132, respectively, and the first isolation region 140 may be located between the first sub-PN junction doped region 131 and the second sub-PN junction doped region 132.

Step S505: a DTI process is used to form a second isolation region 170 extending from the front surface of the substrate to the end face of epitaxial layer 110 remote from the substrate.

Step S506: an anode contact 150 is formed within the P-type doped region 120.

Step S507: a cathode contact 160 is formed within each sub-PN junction doped region.

Accordingly, the present application provides a driving method of a single photon avalanche diode device, which is applied to the single photon avalanche diode device described above, and is specifically described below in connection with fig. 6.

Referring to fig. 6, fig. 6 is a schematic flow chart of a driving method of a single photon avalanche diode device according to an embodiment of the present application, including:

step S601: the anode contact 150 is coupled to a first supply voltage terminal.

Step S602: the cathode contact 160 of the first sub-PN junction doped region 131 and the cathode contact 160 of the second sub-PN junction doped region 132 are coupled to a second supply voltage terminal via quenching resistors, respectively.

Step S603: outputting the first driving voltage to the first power voltage terminal.

Optionally, the first driving voltage may have a voltage value within a range of 3v to 5 v. Alternatively, the first driving voltage may be 3.3V.

Step S604: outputting the second driving voltage to the second power voltage terminal.

Alternatively, the second driving voltage may be-20V.

It should be noted that the specific voltage values of the first driving voltage or the second driving voltage are not limited in this application, and in other alternative embodiments, the first driving voltage and the second driving voltage may also be other voltage values.

Correspondingly, the application provides a ranging method which is applied to the single photon avalanche diode device and a detection circuit of the single photon avalanche diode device. The method will be described with reference to fig. 7, 8 (a) -8 (e) and 9 (a) -9 (c).

Fig. 7 is a flow chart of a ranging method according to an embodiment of the present application. Referring to fig. 7, an exemplary flow of the ranging method may include:

step S701: an optical pulse is emitted to a target object, and a first detection signal output by a first circuit and a second detection signal output by a second circuit are detected.

Fig. 8 (a) is a schematic waveform diagram of an emitted light pulse according to an embodiment of the present application. FIG. 8 (a) illustrates waveforms of emitted light pulses, where the abscissa in the graph may represent time; alternatively, the frequency at which the light pulses are emitted to the target object may be a preset frequency.

Fig. 8 (b) is a schematic waveform diagram of cathode voltages of two sub-pixel devices of a single photon avalanche diode device according to an embodiment of the present application. Fig. 8 (b) illustrates waveforms of cathode voltages of the first and second

sub-pixel devices

410 and 420, respectively, anodes of the first and second

sub-pixel devices

410 and 420 are coupled to a first driving voltage, cathodes are respectively connected in series to a quenching resistor, and then to a second driving voltage. Taking the first sub-pixel device as an example, when avalanche breakdown occurs in the first sub-pixel device, the cathode voltage is reduced and then increased under the partial pressure action of the quenching resistor.

Fig. 8 (c) is a schematic waveform diagram of output signals of two sub-pixel devices of a single photon avalanche diode device according to an embodiment of the present application. Fig. 8 (c) illustrates waveforms of output signals of the first and second

sub-pixel devices

410 and 420, respectively, wherein the illustrated output signals of the first and second

sub-pixel devices

410 and 420 are pulse outputs formed after cathode voltage changes of the first and second

sub-pixel devices

410 and 420 pass through inverters, respectively, and may be denoted as first and second inversion signals.

Fig. 8 (d) is a schematic waveform diagram of output signals of and/or components of a single photon avalanche diode device according to an embodiment of the present application. As illustrated in fig. 8 (d), the first inverted signal and the second inverted signal may form two different output signals, a first detection signal and a second detection signal, through two logic components. As shown in fig. 8 (d), when one of the first inversion signal and the second inversion signal is at a high level, the first detection signal is at a high level, and the equivalent first photon detection efficiency thereof is the sum of the photon detection efficiencies of the first sub-pixel device and the second sub-pixel device; when the first inversion signal and the second inversion signal are at high level at the same time, the second detection signal is at high level, and the equivalent second photon detection efficiency is the product of the photon detection efficiencies of the first sub-pixel device and the second sub-pixel device.

Step S702: first detection photon data is determined from the first detection signal.

Optionally, the first detected photon data characterizes a number of photons detected by the first circuit in each of a plurality of preset time intervals. Wherein the photon number of each preset time interval is data obtained by statistics based on all light pulse emissions in the plurality of light pulse emissions.

Alternatively, the first detected photon data may be determined based on the first detected signal by a time-dependent single photon counting method, that is, a repeated measurement is performed for a single photon to construct a histogram of the detected data, in which information of the first detected photon data may be characterized. Optionally, a plurality of light pulses are emitted according to a preset frequency, the number of photons detected by the first circuit in each preset time interval of a plurality of preset time intervals after a single light pulse is emitted is determined, and the sum of the numbers of photons detected in each preset time interval after a plurality of light pulses are emitted is counted and used as the first detected photon data. Wherein each bin in the histogram of the detection data corresponds to a preset time interval, the abscissa of the histogram is the preset time interval, and the ordinate of the histogram reflects the sum of the number of photons detected per single preset time interval.

Specifically, the sum of the numbers of photons detected by the first circuit at the first preset time interval after each emission in the multiple emission light pulses may be counted sequentially, until the sum of the numbers of photons detected by the first circuit at the second preset time interval after each emission in the multiple emission light pulses reaches the sum of the numbers of photons detected at the last preset time interval after each emission in the multiple emission light pulses. In particular, the sum of the number of photons detected at the first preset time interval after the plurality of light pulses is emitted may include the sum of the number of photons detected at the first preset time interval after the first light pulse is emitted, the number of photons detected at the first preset time interval after the second light pulse is emitted, up to the number of photons detected at the first preset time interval after the last light pulse is emitted, and so on.

Step S703: second detected photon data is determined from the second detection signal.

Optionally, the second detected photon data characterizes a number of photons detected by the second circuit in each of a plurality of preset time intervals. Wherein the photon number of each preset time interval is data obtained by statistics based on all light pulse emissions in the plurality of light pulse emissions.

Alternatively, the second detected photon data may be determined based on the second detected signal by a time-dependent single photon counting method, that is, repeated measurements are performed for a plurality of single photons to construct a histogram of the detected data, in which information of the second detected photon data may be characterized. Alternatively, a plurality of light pulses may be emitted according to a preset frequency, the number of photons detected by the second circuit in each of a plurality of preset time intervals after a single emission of the light pulses is determined, and the sum of the numbers of photons detected in each of the preset time intervals after all of the light pulses are emitted in the plurality of light pulse emissions is counted as the second detected photon data. Wherein each bin in the histogram of the detection data corresponds to a preset time interval, the abscissa of the histogram is the preset time interval, and the ordinate of the histogram reflects the sum of the number of photons detected per single preset time interval.

Specifically, the sum of the numbers of photons detected by the second circuit at the first preset time interval after each emission in the multiple emission light pulses may be counted sequentially, until the sum of the numbers of photons detected by the second circuit at the second preset time interval after each emission in the multiple emission light pulses reaches the sum of the numbers of photons detected at the last preset time interval after each emission in the multiple emission light pulses. In particular, the sum of the number of photons detected at the first preset time interval after the plurality of light pulses is emitted may include the sum of the number of photons detected at the first preset time interval after the first light pulse is emitted, the number of photons detected at the first preset time interval after the second light pulse is emitted, up to the number of photons detected at the first preset time interval after the last light pulse is emitted, and so on.

Alternatively, the first detection photon data may be presented in the form of a component histogram, and the second detection photon data may be presented in the form of a component histogram.

Please refer to fig. 8 (e). Fig. 8 (e) is a schematic diagram of an output histogram of a single photon avalanche diode device according to an embodiment of the present application, where fig. 8 (e) illustrates the number of photons detected by the first circuit accumulated after the multiple pulse emissions in step S702, and the number of photons detected by the second circuit accumulated after the multiple pulse emissions in step S703.

Step S704: first distance information of the target object is determined based on the first detected photon data.

Alternatively, the first distance information of the target object may be determined based on the first detected photon data.

Step S705: second distance information of the target object is determined based on the second detected photon data.

Alternatively, second distance information of the target object may be determined based on the second detected photon data.

In step S704-step S705, as an example, optionally, each preset time interval corresponds to a preset photon return time, that is, for the number of photons returned in each preset time interval, it is considered as the number of photons returned by the preset photon return time at the time of calculation. Specifically, the preset photon return time may be the abscissa of the histogram as illustrated in fig. 8 (e) or fig. 9 (b) -9 (c); the ordinate is the number of photons, and the ordinate information of each histogram may represent the number of photons detected within a preset time interval corresponding to a preset photon return time.

As can be seen from comparison of the two histograms of fig. 8 (e), the number of pulses output by the component is greater than the number of pulses output by the component at the same light intensity, or the histogram corresponding to the component is more saturated than the component.

FIG. 9 (a) is a schematic diagram of the relationship between the distance and the reflected light intensity of a single photon avalanche diode device according to an embodiment of the present application; fig. 9 (b) and 9 (c) are schematic diagrams of output histograms of a plurality of detection distances of a single photon avalanche diode device according to an embodiment of the present application. Fig. 9 (b) and 9 (c) illustrate output histograms of a plurality of detection distances. As illustrated in fig. 9 (a), the reflected light intensity increases as the distance decreases.

As illustrated in fig. 9 (b) and 9 (c), when the detection distance is less than the third distance3, the output histogram is already in a single saturated state because the first photon detection efficiency of the first circuit including or component is high, the sampling rate is high. That is, if the detection distance continues to decrease, the photon number increases, and the photon number reflected on the histogram does not change, so that the actual photon number cannot be represented. At this time, the output histogram is still in an unsaturated state because the second photon detection efficiency of the second circuit including the and component is low, and the sampling rate is low.

When the detection distance is greater than distance3, the intensity of the reflected light gradually tends to the pulse envelope shape due to the long target distance, and the histogram density is higher than the background noise, so that the target distance can be calculated normally through the histogram. However, the second circuit including the and the component has a low sampling rate, so that the histogram formed by the target return light is buried in the background light noise, and the target distance cannot be calculated by the histogram data.

Optionally, determining the first distance information of the target object based on the first detected photon data may include: and determining first distance information of the target object based on the first detection photon data, the preset photon return time corresponding to the preset time interval where each first detection photon data is located and the precision of the time digital conversion module. Determining second distance information of the target object based on the second detected photon data, comprising: and determining second distance information of the target object based on the second detection photon data, the preset photon return time corresponding to the preset time interval where each second detection photon data is located, and the precision of the time-to-digital conversion module.

The first distance information or the second distance information may be determined by the following ranging formula:

Wherein Binn is the nth preset photon return time, in is the detected photon data corresponding to the nth preset photon return time, and WTCS is the precision of the time digital conversion module; when d is the first distance information, the detected photon data is the first detected photon data; and d is second distance information, and the detected photon data is second detected photon data.

Step S706: and determining the first distance information as target distance information under the condition that the first distance information and/or the second distance information meet the first preset condition.

Step S707: and determining the second distance information as target distance information under the condition that the first distance information and/or the second distance information meet the second preset condition.

In an alternative embodiment, the first preset condition may be greater than or equal to a preset distance, and the second preset condition may be less than the preset distance.

Three embodiments of steps S706-S707 are described below: first, when the first distance information and the second distance information both meet a first preset condition, determining the first distance information as target distance information; and determining the second distance information as target distance information when the first distance information and the second distance information both meet a second preset condition. Second, when the average value of the first distance information and the second distance information satisfies a first preset condition, the first distance information is determined as target distance information, and when the average value satisfies a second preset condition, the second distance information is determined as target distance information. Thirdly, when the first distance information meets a first preset condition, determining the first distance information as target distance information; and when the first distance information meets a second preset condition, determining the second distance information as target distance information.

Further elaborated in connection with the ranging equations above. When the output histogram of the or-based component tends to a single saturated state, in+1, in+2 … … is 0, the ranging formula can be simplified as:

the ranging accuracy is only related to the accuracy of the time-to-digital conversion module. Assuming that the accuracy of the time-to-digital conversion module is 1ns, when the distance is too close, the ranging accuracy is 15cm, and the linearity of ranging is deteriorated due to the fact that photon data cannot be accurately obtained. While at this time, the near target can still be measured with high accuracy based on the output histogram of the and component being unsaturated. Therefore, the distance measurement is performed at a short distance by using the detection signal output by the module, that is, the second distance information is used as the target distance information, so that the problem of low short distance measurement precision can be avoided.

And at a greater distance, the output histogram density of the base or component is higher than the background noise, while the output histogram of the base and component is submerged in the background noise. Therefore, the distance measurement is performed by adopting the detection signal output by the or assembly at a long distance, namely, the first distance information is adopted as the target distance information, so that the problem of inaccurate long-distance measurement can be avoided.

Referring to fig. 10, fig. 10 is a schematic diagram of ranging linearity of a ranging method according to an embodiment of the present disclosure. The abscissa of fig. 10 represents the actual distance, and the ordinate represents the measured distance. The solid line may represent the ranging linearity determined based on the first distance information and the actual distance, and the dotted line may represent the ranging linearity determined based on the second distance information and the actual distance. As illustrated in fig. 10, when the detection distance is equal to or greater than the preset distance, the first distance information may be employed as the measurement result, whereas when the detection distance is less than the preset distance, the second distance information may be employed as the measurement result.

According to the embodiment of the application, the detection signal output by the OR gate can be obtained to obtain the first distance information, and the detection signal output by the AND gate can be obtained to obtain the second distance information, so that detection results of different photon detection efficiencies are obtained; by combining the first distance information and the second distance information for distance measurement, the distance measurement precision and linearity of the near distance can be ensured, and the accuracy of the long distance measurement can be ensured.

Accordingly, the present application provides a ranging device. Fig. 11 is a schematic structural diagram of a ranging device according to an embodiment of the present application. As illustrated in fig. 11, the ranging apparatus 1100 is for a single photon avalanche diode device as set forth above. The apparatus may include:

a transmitting module 1101 for transmitting an optical pulse to a target object and detecting a first detection signal output by the first circuit and a second detection signal output by the second circuit;

a first determining module 1102, configured to determine first detection photon data according to the first detection signal; the first detected photon data characterizes the number of photons detected by the first circuit in each of a plurality of preset time intervals;

a second determining module 1103 for determining second detected photon data according to the second detection signal; the second detected photon data comprises the number of photons detected by the second circuit in each preset time interval;

A third determining module 1104 for determining first distance information of the target object based on the first detected photon data;

a fourth determining module 1105 for determining second distance information of the target object based on the second detected photon data;

a first distance module 1106, configured to determine the first distance information as target distance information if the first distance information and/or the second distance information satisfy a first preset condition;

a second distance module 1107, configured to determine the second distance information as target distance information if the first distance information and/or the second distance information satisfy a second preset condition.

Optionally, each preset time interval corresponds to a preset photon return time, and the third determining module 1104 may be configured to: and determining first distance information of the target object based on the first detection photon data, the preset photon return time corresponding to the preset time interval where each first detection photon data is located and the precision of the time digital conversion module.

It is noted that the device, circuit, radar, method, apparatus embodiments provided herein are based on the same inventive concept.

It should be noted that the present specification provides method operational steps as examples, but may include more or fewer operational steps based on conventional or non-inventive labor. The order of steps recited in the embodiments is merely one way of performing the order of steps and does not represent a unique order of execution.

The foregoing description of the preferred embodiments of the present application is not intended to limit the invention to the particular embodiments of the present application, but to limit the scope of the invention to the particular embodiments of the present application.

Claims

1. A single photon avalanche diode device, comprising:

a substrate; the substrate includes a back surface and a front surface opposite the back surface;

an epitaxial layer (110) disposed on the front surface;

the P-type doped region (120), the PN combination doped region (130) and the first isolation region (140) are arranged on the top of the epitaxial layer (110);

wherein, an anode contact (150) is arranged in the P-type doped region (120);

the PN junction doped region (130) comprises a first sub PN junction doped region (131) and a second sub PN junction doped region (132), and the first isolation region (140) is positioned between the first sub PN junction doped region (131) and the second sub PN junction doped region (132);

the first sub PN junction doped region (131) and the second sub PN junction doped region (132) are both provided with cathode contacts (160);

the cathode contact (160) of the first sub-PN junction doped region (131) is connected to the or component (450) and to the component (460) via a first inverter (430), respectively;

-a cathode contact (160) of said second sub-PN junction doped region (132) is connected to said or component (450) and to said and component (460), respectively, through a second inverter (440);

the signal output by the AND component is used for photon detection at a first preset detection distance, or the signal output by the OR component is used for photon detection at a second preset detection distance, and the first preset detection distance is smaller than the second preset detection distance.

2. The single photon avalanche diode device according to claim 1, wherein the first sub-PN junction doped region (131) and the second sub-PN junction doped region (132) comprise a sub-P-type doped region and a sub-N-type doped region located below the sub-P-type doped region.

3. The single photon avalanche diode device according to claim 1, wherein the first isolation region (140) is an STI trench formed using a shallow trench isolation STI process.

4. The single photon avalanche diode device according to claim 1, further comprising:

a second isolation region (170) disposed around the epitaxial layer (110); the second isolation region (170) is a DTI trench formed using a deep trench isolation DTI process.

5. The single photon avalanche diode device according to claim 1, wherein the anode contact (150) is coupled to a first supply voltage terminal;

-a cathode contact (160) of the first sub-PN junction doped region (131) is coupled to a second supply voltage terminal through a first resistor (470); a cathode contact (160) of the second sub-PN junction doped region (132) is coupled to the second supply voltage terminal through a second resistor (480).

6. A detection circuit for a single photon avalanche diode device according to any of claims 1-5, said detection circuit comprising:

-a first circuit connecting the cathode contact (160) of the first sub-PN junction doped region (131) with the or component (450) through a first inverter (430), and connecting the cathode contact (160) of the second sub-PN junction doped region (132) with the or component (450) through a second inverter (440);

and a second circuit connecting the cathode contact (160) of the first sub PN junction doped region (131) to the component (460) through a first inverter (430), and connecting the cathode contact (160) of the second sub PN junction doped region (132) to the component (460) through a second inverter (440).

7. A lidar, comprising:

the transmitting unit is used for providing a transmitting light beam, and the transmitting light beam is reflected by the target object to form an echo light beam;

a receiving unit for receiving an echo beam, said receiving unit comprising a single photon avalanche diode device according to any of claims 1-5.

8. A method of making a single photon avalanche diode device according to any one of claims 1 to 5, comprising:

providing a substrate; the substrate includes a back surface and a front surface opposite the back surface;

forming an epitaxial layer (110) on a front surface of the substrate;

forming a first isolation region (140) on an end face of the epitaxial layer (110) remote from the substrate using an STI process;

forming a P-type doped region (120) and a PN combination doped region (130) on the end surface of the epitaxial layer (110) far away from the substrate; the PN combination doped region comprises a first sub PN combination doped region (131) and a second sub PN combination doped region (132), and the first isolation region (140) is positioned between the first sub PN combination doped region (131) and the second sub PN combination doped region (132);

Forming a second isolation region (170) extending from the front surface of the substrate to an end face of the epitaxial layer (110) remote from the substrate using a DTI process;

-forming an anode contact (150) within the P-type doped region (120);

a cathode contact (160) is formed within the first sub-PN junction doped region (131) and the second sub-PN junction doped region (132).

9. A method of driving a single photon avalanche diode device according to any of claims 1-5, said method comprising:

coupling the anode contact (150) to a first supply voltage terminal;

-coupling the cathode contact (160) of the first sub-PN junction doped region (131) and the cathode contact (160) of the second sub-PN junction doped region (132) to a second supply voltage terminal via a quenching resistor, respectively;

outputting a first driving voltage to the first power supply voltage terminal;

outputting a second driving voltage to the second power supply voltage terminal.

10. A ranging method applied to a detection circuit of a single photon avalanche diode device according to claim 6, said method comprising:

Transmitting an optical pulse to a target object, and detecting a first detection signal output by the first circuit and a second detection signal output by the second circuit;

determining first detection photon data according to the first detection signal; the first detected photon data characterizes the number of photons detected by the first circuit in each of a plurality of preset time intervals;

determining second detection photon data according to the second detection signal; the second detected photon data characterizes the number of photons detected by the second circuit in each of the preset time intervals;

determining first distance information of the target object based on the first detected photon data;

determining second distance information of the target object based on the second detected photon data;

determining the first distance information as target distance information under the condition that the first distance information and/or the second distance information meet a first preset condition;

and determining the second distance information as target distance information under the condition that the first distance information and/or the second distance information meet a second preset condition.

11. A ranging method as defined in claim 10 wherein each of said predetermined time intervals corresponds to a predetermined photon return time,

The determining first distance information of the target object based on the first detected photon data includes:

and determining first distance information of the target object based on the first detection photon data, the preset photon return time corresponding to the preset time interval where each first detection photon data is located, and the precision of a time-to-digital conversion module.