Chip for laser detection, lidar, vehicle, and photodiode

Abstract

The present disclosure relates to the technical field of optoelectronics, and provides a chip for laser detection, a LiDAR, a vehicle, and a photodiode. The chip for laser detection comprises a substrate, an epitaxial layer, an operating circuit, and a protection circuit. The epitaxial layer is formed over the substrate. The operating circuit is formed on the epitaxial layer. The operating circuit comprises a first photodiode and is configured to detect incident laser at an operating voltage. The protection circuit is formed on the epitaxial layer. The protection circuit is connected in parallel to the operating circuit and comprises a second photodiode. The turn-on voltage of the protection circuit is greater than the operating voltage, and the impedance of the protection circuit when it is turned on is less than the impedance of the operating circuit when it is turned on. The present disclosure can reduce the degree of damage caused by electrostatic discharge to operating circuits in chips.

Description

Chip, lidar, vehicle and photodiode for laser detection

[0001] The present disclosure claims priority to Chinese Patent Application No. 202411387055.2, filed September 29, 2024, entitled “Circuit, lidar and vehicle for laser detection,” and Chinese Patent Application No. 202411387038.9, filed September 29, 2024, entitled “Chip, lidar, vehicle and photodiode for laser detection,” the contents of which are incorporated by reference in their entirety in the present application. TECHNICAL FIELD

[0002] The present disclosure relates to the field of optoelectronic technology, and in particular to a chip, a lidar, a vehicle and a photodiode for laser detection. BACKGROUND

[0003] A lidar (LiDAR) can emit laser to an object and receive laser (also called echo) reflected by the object. The lidar can determine information of the object according to the echo. For example, information such as position, speed, attitude, etc. of the object.

[0004] The lidar can be damaged due to electrostatic discharge (ESD) in practical application. ESD is a common phenomenon in nature. ESD can occur on each pin of the chip in a series of processes such as chip production, testing, packaging, transportation and use. When ESD occurs, there will be a voltage much higher than the normal working voltage in the chip of the lidar, and there will also be a transient large current in the circuit. ESD often causes a permanent damage to the chip or a device in the chip, so that the lidar cannot work normally. How to improve the ESD bearing capacity of the chip in the lidar and thus reduce the degree of damage caused by ESD is an important problem. SUMMARY

[0005] The present disclosure provides a chip for laser detection. By setting a protection circuit with a high conduction voltage and a low conduction impedance, the degree of damage caused by ESD to the working circuit can be reduced.

[0006] In a first aspect, the present disclosure provides a chip for laser detection. The chip includes a substrate, an epitaxial layer, a working circuit and a protection circuit. The epitaxial layer is formed above the substrate. The working circuit is formed in the epitaxial layer, and the working circuit includes a first photodiode and is configured to detect incident laser at a working voltage. The protection circuit is formed in the epitaxial layer, and the protection circuit is in parallel with the working circuit and includes a second photodiode. The conduction voltage of the protection circuit is greater than the working voltage, and the impedance of the protection circuit after conduction is less than the impedance of the working circuit after conduction.

[0007] Optionally, the incident laser detected by the working circuit can be a return wave.

[0008] Optionally, the first photodiode comprises a first doped region, a second doped region and a third doped region. The first doped region and the second doped region are of different doping ion types. The second doped region is formed above the third doped region, and the second doped region and the third doped region are of different doping ion types. At least part of the second doped region and at least part of the third doped region form a first depletion region.

[0009] Optionally, the first photodiode further comprises a fourth doped region. The fourth doped region is formed between the first doped region and the second doped region. The doping ion concentration of the second doped region is greater than the doping ion concentration of the fourth doped region, and the doping ion concentration of the third doped region is greater than the ion concentration of the fourth doped region. The doping ion type of the second doped region is the same as the doping ion type of the fourth doped region.

[0010] Optionally, the doping ion concentration of the first doped region is greater than the doping ion concentration of the second doped region, and the doping ion concentration of the first doped region is less than the doping ion concentration of the third doped region.

[0011] Optionally, the first doped region and the third doped region are of P-type, and the second doped region and the fourth doped region are of N-type. The second doped region is configured to be connected to a cathode, and the first doped region is configured to be connected to an anode.

[0012] Optionally, the first doped region and the third doped region are of N-type, and the second doped region and the fourth doped region are of P-type. The second doped region is configured to be connected to an anode, and the first doped region is configured to be connected to a cathode.

[0013] Optionally, the doping ion concentration of the first doped region ranges from 5e16cm -3 to 1e18cm -3 , the doping ion concentration of the second doped region ranges from 1e17cm - 3 to 5e18cm -3 , the doping ion concentration of the third doped region ranges from 5e16cm -3 to 1e18cm -3 , and the doping ion concentration of the fourth doped region ranges from 1e16cm - 3 to 1e18cm -3 .

[0014] Optionally, the doping ion longitudinal distribution of the second photodiode is consistent with that of the first photodiode.

[0015] Optionally, the second photodiode comprises a plurality of series-connected photodiodes, and the plurality of series-connected photodiodes comprises at least one reverse-biased photodiode.

[0016] Optionally, the plurality of series-connected photodiodes comprises at least two reverse-biased photodiodes, or the plurality of series-connected photodiodes comprises one reverse-biased photodiode and a plurality of forward-biased photodiodes.

[0017] Optionally, the second photodiode has a vertical conduction structure, and the doping ions of the first photodiode and the second photodiode are longitudinally distributed differently.

[0018] Optionally, the second photodiode comprises a fifth doped region, a sixth doped region, and a seventh doped region. The fifth doped region and the sixth doped region are of different types of doping ions, the sixth doped region and the seventh doped region are of the same type of doping ions, the seventh doped region is formed between the fifth doped region and the sixth doped region, and the doping ion concentration of the sixth doped region is greater than that of the seventh doped region. The first depletion region has a first breakdown voltage. The substrate, the epitaxial layer, and the sixth doped region correspond to a second breakdown voltage, and the second breakdown voltage is greater than the first breakdown voltage. At least part of the sixth doped region and at least part of the epitaxial layer form a second depletion region; or at least part of the sixth doped region, at least part of the epitaxial layer, and at least part of the substrate form a second depletion region; or at least part of the epitaxial layer and at least part of the substrate form a second depletion region.

[0019] Optionally, the doping ion concentration of the fifth doped region is greater than that of the seventh doped region.

[0020] Optionally, the longitudinal distribution of the doping ions of the first doped region is consistent with that of the fifth doped region, the longitudinal distribution of the doping ions of the second doped region is consistent with that of the sixth doped region, and the longitudinal distribution of the doping ions of the fourth doped region is consistent with that of the seventh doped region.

[0021] Optionally, the fifth doped region is of P-type, and the sixth doped region and the seventh doped region are of N-type. The fifth doped region is configured to be connected to an anode, and the sixth doped region is configured to be connected to a cathode.

[0022] Optionally, the fifth doped region is of N-type, and the sixth doped region and the seventh doped region are of P-type. The fifth doped region is configured to be connected to a cathode, and the sixth doped region is configured to be connected to an anode.

[0023] Optionally, the second photodiode comprises a fifth doped region, a seventh doped region and an eighth doped region. The seventh doped region is formed above the eighth doped region, and the seventh doped region and the eighth doped region form a second depletion region. The first depletion region has a first breakdown voltage, and the second depletion region has a second breakdown voltage. The first breakdown voltage is less than the second breakdown voltage. The eighth doped region has a higher doping ion concentration than the seventh doped region. The fifth doped region and the seventh doped region have different doping ion types, and the seventh doped region and the eighth doped region have different doping ion types.

[0024] Optionally, the fifth doped region has a higher doping ion concentration than the seventh doped region.

[0025] Optionally, the doping ion longitudinal distribution of the first doped region is consistent with the doping ion longitudinal distribution of the fifth doped region. The seventh doped region is larger than the fourth doped region, and the eighth doped region is smaller than the third doped region.

[0026] Optionally, the fifth doped region and the eighth doped region are P-type, and the seventh doped region is N-type. The fifth doped region is configured to be connected to an anode, and the seventh doped region is configured to be connected to a cathode.

[0027] Optionally, the fifth doped region and the eighth doped region are N-type, and the seventh doped region is P-type. The fifth doped region is configured to be connected to a cathode, and the seventh doped region is configured to be connected to an anode.

[0028] Optionally, the vertical conduction structure of the second photodiode comprises the second depletion region formed along the longitudinal direction of the second photodiode.

[0029] Optionally, the number of the second photodiodes is less than the number of the first photodiodes. The area occupied by the protection circuit on the substrate is less than the area occupied by the working circuit on the substrate.

[0030] Optionally, the protection circuit comprises one second photodiode.

[0031] Optionally, the protection circuit comprises a first protection circuit and a second protection circuit connected in parallel with the first protection circuit. The first protection circuit comprises the second photodiode, and the second protection circuit comprises a third photodiode. The impedance of the first protection circuit after being turned on is less than the impedance of the working circuit after being turned on, and the impedance of the second protection circuit after being turned on is less than the impedance of the working circuit after being turned on.

[0032] Optionally, the working circuit further comprises a quenching circuit. The quenching circuit is connected in series with the first photodiode and is configured to restore the bias voltage of the first photodiode after the first photodiode generates avalanche effect.

[0033] Optionally, the chip further comprises a quenching circuit. The quenching circuit is configured to restore the bias voltage of the first photodiode after the avalanche effect of the first photodiode. A first end of the quenching circuit is connected to one end of the working circuit, and the first end of the quenching circuit is connected to one end of the protection circuit.

[0034] Optionally, the quenching circuit comprises a quenching resistor or a metal-oxide semiconductor field effect (MOS) tube.

[0035] In a second aspect, the present disclosure further provides a laser radar. The laser radar comprises a laser and the chip of any one of the first aspect. The chip is configured to receive the echo corresponding to the laser.

[0036] In a third aspect, the present disclosure further provides a carrier. The carrier comprises the laser radar of the second aspect and a connector. The connector is configured to connect the laser radar and the carrier.

[0037] In a fourth aspect, the present disclosure further provides a photodiode. The photodiode comprises a substrate, an epitaxial layer, a first doped region, a second doped region, and a third doped region. The epitaxial layer is formed above the substrate. The first doped region is formed in the epitaxial layer. The second doped region is formed in the epitaxial layer and has a different type of doped ions from the first doped region. The third doped region is formed between the first doped region and the second doped region, and the third doped region has the same type of doped ions as the sixth doped region. Wherein, the second doped region has a higher concentration of doped ions than the third doped region, at least part of the second doped region and at least part of the epitaxial layer form a depletion region; or at least part of the second doped region, at least part of the epitaxial layer, and at least part of the substrate form a depletion region; or at least part of the epitaxial layer and at least part of the substrate form a depletion region.

[0038] Optionally, the first doped region has a higher concentration of doped ions than the third doped region.

[0039] Optionally, the first doped region has a P-type conductivity, and the second doped region and the third doped region have an N-type conductivity. The first doped region is configured to connect an anode, and the second doped region is configured to connect a cathode.

[0040] Optionally, the first doped region has an N-type conductivity, and the second doped region and the third doped region have a P-type conductivity. The first doped region is configured to connect a cathode, and the second doped region is configured to connect an anode.

[0041] Optionally, the first doped region has a concentration of doped ions in a range of 5e16cm-3~1e18cm-3. -3 Optionally, the second doped region has a concentration of doped ions in a range of 1e17cm-3~5e18cm-3. -3 3 -3 ​​; the doping ion concentration of the third doped region ranges from 5e16cm-2to 1e18cm-2. -3 ~1e18cm-2 -3 .

[0042] In a fifth aspect, the present disclosure further provides a photodiode. The photodiode comprises a substrate, an epitaxial layer, a first doped region, a second doped region and a third doped region. The epitaxial layer is formed above the substrate. The first doped region is formed in the epitaxial layer. The second doped region is formed in the epitaxial layer and has a different doping ion type from the first doped region. The third doped region is formed below the second doped region and has a different doping ion type from the second doped region. The doping ion concentration of the third doped region is greater than the doping ion concentration of the second doped region. At least part of the second doped region and at least the third doped region form a depletion region.

[0043] Optionally, the doping ion concentration of the first doped region is greater than the doping ion concentration of the second doped region.

[0044] Optionally, the first doped region and the third doped region are of P-type, and the second doped region is of N-type. The first doped region is configured to be connected to an anode, and the second doped region is configured to be connected to a cathode.

[0045] Optionally, the first doped region and the third doped region are of N-type, and the second doped region is of P-type. The first doped region is configured to be connected to a cathode, and the second doped region is configured to be connected to an anode.

[0046] Optionally, the doping ion concentration of the first doped region ranges from 5e16cm-2to 1e18cm-2. -3 ~1e18cm-2 -3 ; the doping ion concentration of the second doped region ranges from 1e16cm-2to 1e18cm-2. - 3 ~1e18cm-2 -3 ; the doping ion concentration of the third doped region ranges from 5e16cm-2to 1e18cm-2. -3 ~1e18cm-2 -3 .

[0047] In the present disclosure, a protection circuit with high on-voltage and low on-impedance can be arranged in a chip for laser detection, which can reduce the damage degree of ESD to the working circuit. On the basis of the process steps of the first photodiode, the doping ion longitudinal distribution of the second photodiode is changed, so that the doping ion longitudinal distribution of the first photodiode and the second photodiode is different. Thus, the second photodiode can have a higher breakdown voltage in the longitudinal direction, so that it can be used as an ESD protection device. In this way, the design and manufacturing costs of the circuit can be reduced or slightly increased. BRIEF DESCRIPTION OF DRAWINGS

[0048] FIG. 1 shows an example diagram of a lidar consistent with some embodiments of the present disclosure.

[0049] FIG. 2 shows an example diagram of a structure of a circuit consistent with some embodiments of the present disclosure.

[0050] FIG. 3 shows an example diagram of a structure of a circuit in a chip consistent with some embodiments of the present disclosure.

[0051] FIG. 4 shows an example diagram of a structure of a first photodiode consistent with some embodiments of the present disclosure. FIG. 5 shows an example diagram of a circuit structure of a protection circuit consistent with some embodiments of the present disclosure.

[0052] FIG. 6 shows an example diagram of a structure of a protection circuit consistent with some embodiments of the present disclosure.

[0053] FIG. 7 shows an example diagram of a structure of a protection circuit consistent with some embodiments of the present disclosure.

[0054] FIG. 8 shows an example diagram of a structure of a second photodiode consistent with some embodiments of the present disclosure.

[0055] FIG. 9 shows an example diagram of a structure of a second photodiode consistent with some embodiments of the present disclosure.

[0056] FIG. 10 shows an example diagram of a structure of a protection circuit consistent with some embodiments of the present disclosure.

[0057] FIG. 11 shows an example diagram of a structure of a circuit consistent with some embodiments of the present disclosure.

[0058] FIG. 12 shows an example diagram of a structure of a circuit consistent with some embodiments of the present disclosure.

[0059] FIG. 13 shows an example diagram of a structure of a circuit consistent with some embodiments of the present disclosure.

[0060] FIG. 14 shows an example diagram of a structure of a circuit consistent with some embodiments of the present disclosure.

[0061] FIG. 15 shows an example diagram of a structure of a circuit consistent with some embodiments of the present disclosure.

[0062] FIG. 16 shows an example diagram of a structure of a circuit consistent with some embodiments of the present disclosure.

[0063] FIG. 17 shows an example diagram of a structure of a circuit consistent with some embodiments of the present disclosure.

[0064] FIG. 18 shows an example diagram of a structure of a vehicle consistent with some embodiments of the present disclosure.

[0065] FIG. 19 shows a structural example diagram of a protection circuit, consistent with some embodiments of the present disclosure. DETAILED DESCRIPTION

[0066] In the present disclosure, the direction along the thickness direction of the chip substrate or the direction perpendicular to the substrate surface is referred to as the vertical direction. Accordingly, the conductive structure existing in the direction along the thickness direction of the substrate or the direction perpendicular to the substrate surface is referred to as the vertical conductive structure, and the distribution of the doped ions existing in the thickness direction of the substrate is referred to as the longitudinal distribution, for example, the vertical distribution. In some examples, the thickness direction of the substrate refers to the direction extending from the substrate surface to the interior of the substrate at a certain angle range or approximately, such as the direction approximately perpendicular to the substrate surface or the direction oblique to the substrate surface. For example, the angle between the substrate surface is in the following interval (89°-90°], (87°-89°], (85°-87°], (80°-85°], (70°-80°], (60°-70°], (45°-60°], or (30°-45°].

[0067] FIG. 1 shows an example diagram of a lidar, consistent with some embodiments of the present disclosure. Referring to FIG. 1, the lidar 10 includes a laser 100 and a circuit 300 for laser detection. In some embodiments, the circuit 300 can be a circuit integrated together through a semiconductor process. In some embodiments, as shown in FIG. 1, the circuit can also be disposed in a chip 200 (referred to as chip 200) in the lidar 10 for receiving the echo. The laser 100 can emit laser when working. The laser 100 can include one or more lasers. For example, the laser 100 can include a vertical cavity surface emitting laser (VCSEL), a photonic crystal surface emitting laser (PCSEL), or an edge emitting laser (EEL), etc. The laser emitted by the laser 100 to the object will be reflected by the object to form an echo. The circuit 300 can receive the echo when working. The chip 200 can receive the echo when working. In some embodiments, the chip 200 can be made through steps such as design, wafer fabrication, package fabrication, etc. The chip 200 can have strong ESD withstand capability.

[0068] In some embodiments, the circuit includes the working circuit 230 and the protection circuit 240 connected in parallel with the working circuit 230.

[0069] FIG. 2 shows a structural example diagram of a circuit consistent with some embodiments of the present disclosure. Referring to FIG. 2, the working circuit 230 includes the first photodiode 231. The working circuit 230 can detect echoes at a working voltage.

[0070] For example, the first photodiode 231 can include an avalanche photodiode (APD), a single photon avalanche photodiode (SPAD), or a silicon photomultiplier (SiPM), etc. In some embodiments, the first photodiode 231 can be formed on the epitaxial layer 220 by ion diffusion, photolithography, etching, etc.

[0071] In some embodiments, the working circuit 230 can include a plurality of first photodiodes 231 connected in parallel. For example, the working circuit 230 can include 3 first photodiodes 231 connected in parallel. For another example, the working circuit 230 can include 2 or more first photodiodes 231 connected in parallel. The plurality of first photodiodes 231 can work simultaneously or at different times by gating.

[0072] In some embodiments, the working circuit 230 can include a first end 230A and a second end 230B. The first end 230A can be electrically connected to the cathode of the first photodiode 231. The second end 230B can be electrically connected to the anode of the first photodiode 231. Electrical connection can mean direct connection or indirect connection through other elements. When the working circuit 230 is working, the voltage applied to the first end 230A can be higher than the voltage applied to the second end 230B. For example, the second end 230B is grounded, and the first end 230A is connected to a forward voltage. The anode of the first photodiode 231 is connected to a low voltage, and the cathode is connected to a high voltage. The first photodiode 231 is in a reverse bias state. When the reverse voltage across the first photodiode 231 continuously increases, the first photodiode 231 can be reverse-broken down, thereby detecting photons. The working circuit 230 can detect echoes at a working voltage. The working voltage refers to the voltage value within the voltage range that can make the working circuit 230 work normally. The working voltage can be represented by the voltage difference between the first end 230A and the second end 230B. For example, a photodiode can normally respond to received photons and generate an electrical signal within a certain voltage range. If the voltage applied across the photodiode exceeds the voltage range, the PN junction of the photodiode can be broken down, damaging the device.

[0073] The operating voltage can be determined according to different scenarios or devices used. For example, for an APD working in Geiger mode, the operating voltage applied across the APD generally needs to be greater than the reverse breakdown voltage (BV) of the APD. For example, for an APD working in linear mode, the operating voltage applied across the APD is generally less than the BV of the APD. However, if the operating voltage applied across the APD exceeds the BV of the APD, it is possible to break the PN junction of the APD, damaging the device.

[0074] In some embodiments, the incident laser detected by the operating circuit 230 at the operating voltage can be a return wave. For example, the lidar 10 emits laser to an object through the laser 100. The lidar 10 can receive the return wave reflected by the object through the operating circuit 230.

[0075] In some embodiments, the operating voltage is the voltage difference between the first end 230A and the second end 230B when the first photodiode 231 is reverse breakdown. When the operating voltage increases to the point that the first photodiode 231 is reverse breakdown, the first photodiode 231 can sensitively detect photons. In some embodiments, the operating voltage is equal to the BV of the first photodiode 231. In some embodiments, the operating voltage can also be greater than the BV of the first photodiode 231. For example, the operating voltage can be greater than or equal to the sum of the BV and an over voltage (OV), so that the first photodiode 231 is in a state capable of sensitively detecting photons. For example, the operating voltage can be the voltage sum of the BV and the OV. The OV can be several volts (V) to tens of V.

[0076] In some embodiments, the operating circuit 230 further includes a quenching circuit 233. The quenching circuit 233 can be in series with the first photodiode 231. For example, please continue to refer to FIG. 2, the operating circuit 230 can include a plurality of quenching circuits 233. One quenching circuit 233 can be in series with one first photodiode 231. The first end 230A of the operating circuit 230 is electrically connected with the quenching circuit 223, and the second end 230B of the operating circuit 230 is electrically connected with the first photodiode 231.

[0077] The quenching circuit 233 can restore the bias voltage of the first photodiode 231 after the first photodiode 231 occurs avalanche effect. For example, after the first photodiode 231 occurs avalanche, the quenching circuit 233 can reduce the voltage across the first photodiode 231, so that it cannot continue to occur avalanche.

[0078] In some embodiments, the quenching circuit 233 comprises a quenching resistor. For example, there is a structure of a photodiode in series with a quenching resistor in the SiPM chip. Please continue to refer to FIG. 2, one quenching resistor can be in series with the first photodiode 231.

[0079] In some embodiments, the quenching circuit 233 can comprise a metal-oxide semiconductor field effect (MOS) tube. The MOS tube can utilize its voltage control function to rapidly reduce the reverse bias voltage of the photodiode when an avalanche occurs, achieve rapid quenching, and thus reduce the recovery time of the device.

[0080] Please continue to refer to FIG. 2, the protection circuit 240 is in parallel with the working circuit 230. The two ends of the protection circuit 240 can be electrically connected with the first end 230A and the second end 230B of the working circuit 230 respectively. For example, the first end 2 of the protection circuit 240 is electrically connected with the first end 230A of the working circuit 230, and the second end of the protection circuit 240 is electrically connected with the working circuit 230B.

[0081] In some embodiments, when the working circuit 230 comprises the first photodiode 231, the protection circuit 240 can be in parallel with the first photodiode 231, thereby achieving protection of the working circuit 230. In some embodiments, when the working circuit 230 further comprises the quenching circuit 233, the first end of the protection circuit 240 can be electrically connected with the first photodiode 231, and the second end of the protection circuit 240 can be electrically connected with the quenching circuit 233. In this way, protection of the entire working circuit 230 can be achieved. In some embodiments, the circuit 300 can further comprise other circuit structures. The protection circuit 240 can also protect part of the other circuit structures.

[0082] The turn-on voltage of the protection circuit 240 is greater than the working voltage of the working circuit 230, and the impedance of the protection circuit 240 after being turned on is smaller than the impedance of the working circuit 230 after being turned on. The impedance can be an equivalent impedance. When the working circuit 230 is working, the working voltage is applied to the working circuit 230. Since the turn-on voltage of the protection circuit 240 is greater than the working voltage, the protection circuit 240 is not turned on at this time. The protection circuit 240 is in an off state. In this way, when the working circuit 230 is working, the protection circuit 240 will not affect the normal work of the working circuit 230. When the ESD phenomenon occurs, there can be a voltage higher than the working voltage in the circuit, and there can also be a transient large current in the circuit. This can cause the chip and the circuit in the chip to form a permanent damage, affecting the function of the lidar 10. For example, when an electrostatic voltage is applied across the working circuit 230, the electrostatic voltage is usually higher than the breakdown voltage of the first photodiode 231 itself. This can cause the first photodiode 231 to be broken down and irreversibly damaged. The first photodiode 231 cannot work normally, thereby affecting the normal work of the lidar 10. After the protection circuit 240 is set, when the ESD phenomenon occurs, the electrostatic voltage is applied to the protection circuit 240 at the same time because the protection circuit 240 is in parallel with the working circuit 230. Since the electrostatic voltage is much higher than the working voltage, the protection circuit 240 is turned on at this time. The impedance of the working circuit 230 after being turned on is at least the impedance of the quenching resistor. The impedance of the protection circuit 240 after being turned on is smaller than or much smaller than the impedance of the working circuit 230 after being turned on, and the protection circuit 240 can provide a low-impedance turn-on path for the transient large current. This will make the transient large current more shunted to the protection circuit 240, thereby clamping the high voltage generated by the ESD in a lower voltage range. The voltage applied to the working circuit 230 is also clamped in a lower voltage range. By setting a high turn-on voltage and a low-impedance protection circuit 240, the degree of damage caused by ESD to the working circuit 230 can be reduced.

[0083] In some embodiments, at least one of the working circuit 230 and the protection circuit 240 in parallel with the working circuit 230 can be integrated in a chip. For example, the working circuit 230 can be integrated in a chip. For example, the protection circuit 240 can be integrated in a chip. For example, both the working circuit 230 and the protection circuit 240 can be integrated in a chip. FIG. 3 shows a structure example diagram of a circuit in a chip, which is consistent with some embodiments of the present disclosure. Referring to FIG. 3, the chip 200 includes a substrate 210, an epitaxial layer 220, and a circuit (not shown in FIG. 3).

[0084] Substrate 210 provides mechanical support in semiconductor device fabrication, maintaining the shape and dimensional stability of the device. The structure and properties of substrate 210 can also affect the electrical and structural characteristics of the device. Substrate 210 can provide a physical platform for forming circuits. Different electronic circuit structures, such as operational circuit 230 and protection circuit 240, can be built on substrate 210. In some embodiments, substrate 210 is silicon-based. In some embodiments, substrate 210 is a semiconductor substrate doped with P-type impurities. For example, the P-type impurities can be boron, aluminum, and gallium, etc. In some embodiments, substrate 210 is a substrate doped with N-type impurities. For example, the N-type impurities can be phosphorus, arsenic, and antimony, etc.

[0085] Epitaxial layer 220 is formed above substrate 210. Epitaxial layer 220 can be formed directly on substrate 210. Epitaxial layer 220 can also be formed indirectly on substrate 210, such as with a SiO2 isolation layer between epitaxial layer 220 and substrate 210. Epitaxial layer 220 can be formed above substrate 210 by chemical vapor deposition, molecular beam epitaxy, or other crystal growth techniques. By controlling the doping type and concentration of epitaxial layer 220, the performance and electrical characteristics of the device can be optimized. In some embodiments, epitaxial layer 220 can be undoped. For example, an intrinsic epitaxial layer. In some embodiments, epitaxial layer 220 can be a P-type doped epitaxial layer 220. By introducing P-type doping during growth, a P-type doped epitaxial layer can be grown on substrate 210. In some embodiments, epitaxial layer 220 can be an N-type doped epitaxial layer 220. By introducing N-type doping during growth, a P-type doped epitaxial layer can be grown on substrate 210.

[0086] In some embodiments, at least one of operational circuit 230 and protection circuit 240 can be formed in epitaxial layer 220. For example, operational circuit 230 can be formed in epitaxial layer 220. For example, protection circuit 240 can be formed in epitaxial layer 220. For example, operational circuit 230 and protection circuit 240 can be formed in epitaxial layer 220. For example, operational circuit 230 and protection circuit 240 can be formed in the same epitaxial layer or different epitaxial layers. For example, referring to FIG. 3, operational circuit 230 is formed on one side of epitaxial layer 220, and protection circuit 240 is also formed on one side of epitaxial layer 220. In some embodiments, chip 200 can also include other circuit structures. Other circuit structures can also be formed in epitaxial layer 220. Exemplary structures of other circuits will be described later.

[0087] FIG. 4 shows a structural diagram of a first photodiode, according to some embodiments of the present disclosure. Referring to FIG. 4, the first photodiode 231 includes a first doped region 231 A, a second doped region 231 B, and a third doped region 231 C. The second doped region 231 B is formed above the third doped region 231 C, for example, the third doped region 231 C is away from a side of the substrate 210.

[0088] In some embodiments, the first doped region 231 A can be a ring-shaped region. The ring-shaped first doped region 231 A can be formed in a peripheral region of the epitaxial layer 220. In some embodiments, the first photodiode 231 can include two first doped regions 231 A. For example, the first photodiode 231 includes one first doped region 231 A on the left side and one first doped region 231 A on the right side.

[0089] In some embodiments, the first doped region 231 A has a different ion doping type than the second doped region 231 B, the second doped region 231 B has a different ion doping type than the third doped region 231 C, and the first doped region 231 A has the same ion doping type as the third doped region 231 C. In some embodiments, the first doped region 231 A and the third doped region 231 C are doped with P-type impurities, and the second doped region 231 B is doped with N-type impurities. Accordingly, the first doped region 231 A and the third doped region 231 C have a P-type conductivity, and the second doped region 231 B has an N-type conductivity. The first doped region 231 A can be connected to an anode, and the second doped region 231 B can be connected to a cathode. In some embodiments, the first doped region 231 A and the third doped region 231 C are doped with N-type impurities, and the second doped region 231 B is doped with P-type impurities. Accordingly, the first doped region 231 A and the third doped region 231 C have an N-type conductivity, and the second doped region 231 B and the fourth doped region 231 D have a P-type conductivity. The second doped region 231 B can be connected to a cathode, and the first doped region 231 A can be connected to an anode.

[0090] In some embodiments, the substrate 210 can also be connected to an electrode. For example, when the second doped region 231 B has an N-type conductivity and the substrate 210 is a P-type substrate, the second doped region 231 B can be connected to a cathode, and the substrate 210 can be connected to an anode. For another example, when the second doped region 231 B has a P-type conductivity and the substrate 210 is an N-type substrate, the second doped region 231 B can be connected to an anode, and the substrate 210 can be connected to a cathode.

[0091] The second doped region 231B and the third doped region 231C have different conductive types. At least part of the second doped region 231B can form a first depletion region R1 with at least part of the third doped region 231C. The first depletion region R1 is a high-resistance region in which the number of carriers under the dual influence of drift motion and diffusion is very small. At least part of the second doped region 231B can form a PN junction with at least part of the third doped region 231C and a corresponding first depletion region R1.

[0092] In some embodiments, the second doped region 231B can have a width slightly greater than the third doped region 231C, for example, as shown in FIG. 4. The bottom of the second doped region 231B can also be in contact with other regions. For example, the second doped region 231B can be in contact with the epitaxial layer 220. Part of the second doped region 231B can form a PN junction with the third doped region 231C and form a first depletion region R1.

[0093] In some embodiments, the first depletion region R1 has a first breakdown voltage. At the first breakdown voltage, the PN junction corresponding to the first depletion region R1 can be broken down, causing the first photodiode 231 to be broken down. For example, the first breakdown voltage can be the BV of the first photodiode 231.

[0094] In some embodiments, the first photodiode 231 further includes a fourth doped region 231D. The fourth doped region 231D is formed between the first doped region 231A and the second doped region 231B, for example, as shown in FIG. 4. For example, the fourth doped region 231D can surround part of the second doped region 231B and part of the third doped region 231C. The second doped region 231B and the fourth doped region 231D can be separated by the epitaxial layer 220.

[0095] In some embodiments, the second doped region 231B and the fourth doped region 231D have the same type of doping ions. For example, the second doped region 231B and the fourth doped region 231D can be doped with N-type impurities. Accordingly, the second doped region 231B and the fourth doped region 231D have a P-type conductive type. For another example, the second doped region 231B and the fourth doped region 231D can be doped with P-type impurities. Accordingly, the second doped region 231B and the fourth doped region 231D have an N-type conductive type.

[0096] The doping ion concentration of the different doped regions can be the same or different. In some embodiments, the doping ion concentration of the second doped region 231B can be greater than the doping ion concentration of the fourth doped region 231D, and the doping ion concentration of the third doped region 231C can be greater than the ion concentration of the fourth doped region 231D. In some embodiments, the doping ion concentration of the first doped region 231A can be greater than the doping ion concentration of the second doped region 231B, and the doping ion concentration of the first doped region 231A can be less than the doping ion concentration of the third doped region 231C. In some embodiments, the doping ion concentration of the first doped region 231A can be equal to the doping ion concentration of the third doped region 231C.

[0097] In some embodiments, the doping ion concentration range of the first doped region 231A can include 5e16cm -3 ~1e18cm -3 . The doping ion concentration range of the second doped region 231B can include 1e17cm -3 ~5e18cm -3 . The doping ion concentration range of the third doped region 231C can include 5e16cm -3 ~1e18cm -3 . The doping ion concentration range of the fourth doped region 231D includes 1e16cm -3 ~1e18cm -3 By changing the doping ion concentration of the doped regions, the conductivity, breakdown voltage, optical performance, etc. of the photodiode can be changed. The doping ion concentration of the doped regions can be selected according to the design requirements of the device.

[0098] By setting the fourth doped region 231D, the possibility of the first photodiode 231 being laterally broken down can be reduced. The doping ion types of the first doped region 231A and the second doped region 231B are different, and the doping ion concentration of the second doped region 231B is relatively large, so the first doped region 231A and the second doped region 231B are prone to form a lateral conductive structure. By setting the fourth doped region 231D with a relatively low doping ion concentration, the first doped region 231A and the second doped region 231B can be prevented from being in contact, so as to reduce the probability of forming a depletion region. Thus, the internal electric field existing in the lateral direction of the first photodiode 231 is suppressed, so as to reduce the probability of the first photodiode 231 being laterally broken down.

[0099] In some embodiments, there can be other depletion regions in the first photodiode 231 in addition to the first depletion region R1. For example, the P-type doped epitaxial layer 220 and the fourth depletion region 231D. For example, where the third depletion region 231C and the fourth depletion region 231D meet, a PN junction and a corresponding depletion region can be formed. The width of a depletion region is inversely proportional to the doping ion concentration of the region. When the doping ion concentration is higher, the depletion region is relatively narrower; when the doping ion concentration is lower, the depletion region is relatively wider. The wider the width of the depletion region, the higher the breakdown voltage is generally. Since the second depletion region 231B and the third depletion region 231C have relatively high concentrations, the first depletion region R1 formed by the two has a relatively narrow width and a relatively low breakdown voltage. When the PN junction corresponding to the first depletion region R1 is broken down, the PN junction corresponding to the other depletion region can not have been broken down yet, but at this time it can be considered that the first photodiode 231 has been broken down. It can be considered that the breakdown voltage of a photodiode is mainly determined by the doping ion region that forms a relatively narrow depletion region. For example, the breakdown voltage of the first photodiode 231 is mainly determined by the second doping region 231B and the third doping region 231C.

[0100] FIG. 5 shows an example circuit structure diagram of a protection circuit, consistent with some embodiments of the present disclosure. Referring to FIG. 5, the protection circuit 240 includes a second photodiode 241. In some embodiments, the on voltage of the protection circuit 240 can be the voltage at which the second photodiode 241 is reversely broken down.

[0101] In some embodiments, the protection circuit 240 can include only one second photodiode 241. The on voltage of the protection circuit 240 is the BV of the second photodiode 241. In some embodiments, the protection circuit 240 can include multiple second photodiodes 241.

[0102] In some embodiments, the second photodiode 241 has a doping ion longitudinal distribution consistent with that of the first photodiode 231. The doping ion longitudinal distribution consistent can mean that the first photodiode 231 and the second photodiode 241 have the same manufacturing process steps in the longitudinal direction of the diode, or that one has a subset of the manufacturing process steps of the other. For example, the first photodiode 231 and the second photodiode 241 have the same doping ion concentration, the same doping ion depth, or the same relative position of the doping ion region, etc. in the longitudinal direction. In this way, if the working circuit 230 and the protection circuit 240 are both part of an integrated circuit formed on a chip substrate, the first photodiode 231 and the second photodiode 241 can be generated at the same time through the same process steps, without the need to design one or more process steps for one of the photodiodes alone, thereby simplifying the manufacturing process of the chip and saving the manufacturing cost of the chip.

[0103] In some embodiments, the first photodiode 231 and the second photodiode 241 have the same physical structure. For example, the first photodiode 231 and the second photodiode 241 have the same doping ion distribution in the lateral direction. The first photodiode 231 and the second photodiode 241 are the same. For example, the first photodiode 231 and the second photodiode 241 are the same model of APD. The first photodiode 231 and the second photodiode 241 have the same BV. That is, the first photodiode 231 used for echo detection is used as the second photodiode 241. Because the original device is used as the ESD protection device, there is no need to develop a new ESD protection device, and the design and manufacturing costs of the device are not increased, and the process steps are not increased.

[0104] In some embodiments, the first photodiode 231 and the second photodiode 241 have different doping ion distributions in the lateral direction. For example, the doping ion region in the second photodiode 241 has a larger lateral area to increase the upper limit of the current passing through. For example, when manufacturing the second photodiode 241, the mask area used when manufacturing the first photodiode 231 is changed. Thus, by increasing the ion doping region of the second photodiode 241, the upper limit of the passing current of the second photodiode is increased. Because the ESD protection device is obtained on the basis of the original device, the process design and manufacturing costs are less increased.

[0105] The SiPM chip and the SPAD chip originally have photodiode structures. Therefore, for the SiPM chip and the SPAD chip, the original photodiode structure can be used as the ESD protection device. In this way, for the SiPM chip and the SPAD chip, there is no need to develop a special ESD protection device, and there is no need for additional process steps. Thus, the design cost and manufacturing cost of the device are not increased. Moreover, the original photodiode in the SiPM chip and the SPAD chip is a diode with a vertical conduction structure. Compared with a diode with a lateral conduction structure, the photodiode also has a stronger current passing capability. Moreover, the photodiode has an advantage in circuit or chip area occupation and occupies less area.

[0106] In some embodiments, the second photodiode 241 can include a plurality of series-connected photodiodes. The plurality of series-connected photodiodes can include at least one reverse-biased photodiode. By arranging a plurality of series-connected photodiodes, the opening voltage of the protection circuit 240 can be increased. In this way, under the working voltage, the protection circuit 240 is not turned on, so as not to affect the normal work of the working circuit 230.

[0107] In some embodiments, the plurality of series-connected photodiodes includes at least two reverse-biased photodiodes. For example, the second photodiode 241 includes three series-connected, reverse-biased photodiodes. For another example, the second photodiode 241 includes two series-connected, reverse-biased photodiodes. FIG. 6 shows a structural example diagram of a protection circuit, consistent with some embodiments of the present disclosure. Referring to FIG. 6, the second photodiode 241 includes two reverse-biased photodiodes. For example, the BV of one photodiode is about 20 V, and the impedance of one photodiode after breakdown is about 5 ohms (Ω) to 10 Ω. The quenching resistor has a resistance of 150 kilo-ohms (KΩ). The working voltage of the working circuit 230 is 25 V, and the impedance of the working circuit 230 after conduction is about 150 KΩ. The conduction voltage of the protection circuit 240 in FIG. 3 is about 40 V, and the impedance of the protection circuit 240 after conduction is about 10 Ω to 20 Ω. The conduction voltage of the protection circuit 240 is greater than the working voltage, and the impedance of the protection circuit 240 after conduction is less than the impedance of the working circuit 230 after conduction.

[0108] Under the working voltage, the working circuit 230 is conducted and the protection circuit 240 is not conducted, so the protection circuit 240 does not affect the normal operation of the working circuit 230. In the case of ESD, the protection circuit 240 is conducted. Because the impedance of the protection circuit 240 (e.g., 10 Ω to 20 Ω) is much smaller than the impedance of the working circuit 230 after conduction (e.g., 150 KΩ), the protection circuit 240 is approximately a short circuit. The transient large current is more shunted to the protection circuit 240, so the protection circuit 240 can reduce the degree of damage to the working circuit 230 caused by ESD.

[0109] In some embodiments, the plurality of series-connected photodiodes can also include one reverse-biased photodiode and a plurality of forward-biased photodiodes. FIG. 7 shows a structural example diagram of a protection circuit, consistent with some embodiments of the present disclosure. Referring to FIG. 7, the second photodiode 241 includes one reverse-biased photodiode and twenty forward-biased photodiodes (only five forward-biased photodiodes are shown in FIG. 7). For example, the BV of one photodiode is about 20 V, and the impedance of one photodiode after breakdown is about 5 Ω to 10 Ω. The forward turn-on voltage of one photodiode is about 0.7 V, and the impedance after forward conduction is about 50 Ω. The quenching resistor has a resistance of 150 KΩ. Accordingly, the impedance of the working circuit 230 after conduction is about 150 KΩ, and the working voltage of the working circuit 230 is 25 V. The conduction voltage of the protection circuit 240 in FIG. 7 is about 34 V, and the impedance of the protection circuit 240 after conduction is about 1.005 KΩ to 1.01 KΩ. The conduction voltage of the protection circuit 240 is greater than the working voltage, and the impedance of the protection circuit 240 after conduction is less than the impedance of the working circuit 230 after conduction.

[0110] At the working voltage, the protection circuit 240 is not turned on and does not affect the normal working of the working circuit 230. At the static voltage, the protection circuit 240 is turned on. Since the impedance of the protection circuit 240 (e.g., 1.005KΩ-1.01KΩ) is smaller than the impedance of the working circuit 230 after being turned on (e.g., 150KΩ), more transient current is shunted to the protection circuit 240. Therefore, the protection circuit 240 can reduce the damage of ESD to the working circuit 230, or make the working circuit 230 not be damaged.

[0111] Under the condition that the protection circuit 240 has a high turn-on voltage and a low impedance, the number of the second photo diodes 241 can be determined according to the requirements of circuit cost, chip area, board area, etc. For example, the working circuit 230 includes M photo diodes in parallel, and M quench resistors. One quench resistor is in series with one photo diode. The protection circuit 240 includes N photo diodes in series. Among them, N1 photo diodes are reversely biased, and N2 photo diodes are forward biased. N, N1 and N2 are positive integers, and N=N1+N2. The BV of the reversely biased photo diode is V BV , the OV of the reversely biased photo diode is V OV , and the impedance after breakdown is R BR . The forward opening voltage of the forward biased photo diode is U ON , and the impedance is R ON . The turn-on voltage of the protection circuit 240 is N1×V BV +N2×U ON , and the impedance of the protection circuit 240 after being turned on is N1×R BR +N2×R ON . The working voltage of the working circuit 230 is V BV +V OV . The impedance of the quench resistor is R CU , and the impedance of the working circuit 230 after being turned on is (R CU +R BR ) / M. For another example, the protection circuit 240 includes N photo diodes in series. The working circuit 230 includes one photo diode and a quench resistor in series with the photo diode. The turn-on voltage of the protection circuit 240 is N1×V BV +N2×U ON , and the impedance of the protection circuit 240 after being turned on is N1×R BR +N2×R ON . The working voltage of the working circuit 230 is V BV +V OV . The impedance of the quench resistor is R CU, the impedance of the working circuit 230 after being turned on is R CU +R BR .

[0112] The protection circuit 240 can have a high turn-on voltage, and under the working voltage, the protection circuit 240 does not affect the normal work of the working circuit 230. The working voltage (e.g., V BV +V OV ) is less than the turn-on voltage (e.g., N1xV BV +N2xU ON ). The protection circuit 240 needs to have a low impedance, and the protection circuit 240 can provide a low-impedance turn-on path for instantaneous large current. Therefore, the impedance of the protection circuit 240 after being turned on (e.g., N1xR BR +N2xR ON ) is less than the impedance of the working circuit 230 after being turned on (e.g., (R CU +R BR ) / M). The specific values of N1 and N2 can be selected according to different requirements after meeting the above relationship.

[0113] In some embodiments, the second photodiode 241 can have a vertical conductive structure. As mentioned before, in this disclosure, a conductive structure existing along the thickness direction of the substrate or the direction perpendicular to the substrate surface is referred to as a vertical conductive structure. Compared with a photodiode having a lateral conductive structure extending along the substrate surface direction, the second photodiode 241 having a vertical conductive structure occupies less surface area of the substrate 210 and has a stronger current-carrying capacity.

[0114] For example, the second photodiode can be different from the first photodiode. For example, the second photodiode 241 can have a different longitudinal distribution of doping ions than the first photodiode 231. The longitudinal direction can refer to the vertical direction. For example, in the thickness direction of the substrate, the two photodiodes have different distributions of doping ions. For another example, in the direction perpendicular to the substrate surface, the two photodiodes have different distributions of doping ions. The different longitudinal distributions of doping ions can be due to different manufacturing process steps of the first photodiode 231 and the second photodiode 241 in the longitudinal direction of the diode. The different longitudinal distributions of doping ions can be that the first photodiode 231 and the second photodiode 241 have different doping ion concentrations, different doping ion depths, different doping ion types, or different relative positions of doping ion regions in the longitudinal direction, etc.

[0115] On the basis of the manufacturing process steps of the first photodiode 231, by changing or reducing some of the manufacturing process steps, the doping ions of the first photodiode 231 and the second photodiode 241 can be different and can be manufactured simultaneously through the same manufacturing process. In some embodiments, the manufacturing process steps of the second photodiode 241 are a subset of the manufacturing process steps of the first photodiode 231. In some embodiments, the manufacturing process steps of the second photodiode 241 are obtained by making minor changes to the manufacturing process steps of the first photodiode 231. In this way, since the working circuit 230 and the protection circuit 240 are both part of the integrated circuit formed on the chip substrate, the first photodiode 231 and the second photodiode 241 can be generated simultaneously through the same or similar manufacturing process steps, thereby simplifying the manufacturing process of the chip and saving the manufacturing cost of the chip.

[0116] FIG. 8 shows a structural example diagram of a second photodiode, consistent with some embodiments of the present disclosure. Referring to FIG. 8, the second photodiode 241 includes a fifth doped region 241E, a sixth doped region 241F, and a seventh doped region 241G. The seventh doped region 241G is formed between the fifth doped region 241E and the sixth doped region 241F. For example, the seventh doped region 241G can surround the sixth doped region 241F. The seventh doped region 241G and the fifth doped region 241E can be separated by an epitaxial layer 220.

[0117] In some embodiments, the doping ion type of the fifth doped region 241E and the sixth doped region 241F is different, and the doping ion type of the sixth doped region 241F and the seventh doped region 241G is the same. For example, the conductivity type of the fifth doped region 241E can be P-type, and the conductivity type of the sixth doped region 241F and the seventh doped region 241G can be N-type. The fifth doped region 241E can be connected to the anode, and the sixth doped region 241F can be connected to the cathode. For another example, the conductivity type of the fifth doped region 241E can be N-type, and the conductivity type of the sixth doped region 241F and the seventh doped region 241G can be P-type. The fifth doped region 241E can be connected to the cathode, and the sixth doped region 241F can be connected to the anode.

[0118] In some embodiments, the substrate 210 can also be connected to the electrode. For example, when the conductivity type of the sixth doped region 241F is N-type and the substrate 210 is a P-type substrate, the sixth doped region 241F can be connected to the cathode, and the substrate 210 can be connected to the anode. For another example, when the conductivity type of the sixth doped region 241F is P-type and the substrate 210 is an N-type substrate, the sixth doped region 241F can be connected to the anode, and the substrate 210 can be connected to the cathode.

[0119] In some embodiments, at least part of the sixth doped region 241F, at least part of the epitaxial layer 220, and at least part of the substrate 210 form a second depletion region R2. For example, the epitaxial layer 220 is of a different conductivity type than the sixth doped region 241F. Referring to FIG. 8, at least part of the sixth doped region 241F and at least part of the epitaxial layer 220 form the second depletion region R2. For another example, the epitaxial layer 220 is of the same conductivity type as the sixth doped region 241F, and the epitaxial layer 220 is of a different conductivity type than the substrate 210. At least part of the epitaxial layer 220 and at least part of the substrate 210 form the second depletion region R2.

[0120] As mentioned before, the second photodiode 241 includes a vertical conduction structure. The vertical conduction structure can include a second depletion layer R2 of the second photodiode formed along a thickness direction of the substrate (i.e., in a vertical direction). The second depletion region R2 can have a second breakdown voltage. At the second breakdown voltage, a corresponding PN junction of the second depletion region R2 can be broken down, and in turn, the second photodiode 241 can be broken down. The first depletion region R1 described before has a first breakdown voltage. Moreover, the first breakdown voltage can be less than the second breakdown voltage. This allows the second photodiode 241 to have a high on-voltage and a low on-resistance characteristic. By having only one or a few second photodiodes 241 in the protection circuit 240, the normal operation of the working circuit 230 can not be affected, and a low impedance path can be provided for the transient high current of ESD. This can allow the protection circuit 240 to occupy a small area on the chip, and can not increase the area cost too much, and can improve the integration and yield of the chip.

[0121] In some embodiments, the second photodiode 241 has a small thickness in a longitudinal direction, and a small thickness in a thickness direction of the substrate. The sixth doped region 241F is close to the epitaxial layer 220 and the substrate 210. When the corresponding PN junction of the second depletion region R2 is broken down, the sixth doped region 241F, the epitaxial layer 220, and the substrate 210 can all be broken down.

[0122] For example, the second breakdown voltage of the second photodiode 241 can be determined by the sixth doped region 241F, the epitaxial layer 220, and the substrate 210. The doping ion concentration of the substrate 210 and the epitaxial layer 220 is very low, so that the second depletion region R2 has a breakdown voltage greater than the first depletion region R1. In this way, a photodiode 241 with a larger breakdown voltage can be manufactured, and a protection circuit 240 with a high on-voltage can be achieved using a small number of photodiodes 241. This can allow the protection circuit 240 to occupy a small area on the chip, and can not increase the area cost too much, and can improve the integration and yield of the chip.

[0123] The doping ion concentration of the different doped regions can be the same or different. In some embodiments, the doping ion concentration of the sixth doped region 241F can be greater than the doping ion concentration of the seventh doped region 241G. In some embodiments, the doping ion concentration of the fifth doped region 241E can be greater than the doping ion concentration of the seventh doped region 241G. For example, the doping ion concentration of the fifth doped region 241E can range from 5e16cm -3 ~1e18cm -3 . The doping ion concentration of the sixth doped region 241F can range from 1e17cm -3 ~5e18cm -3 . The doping ion concentration of the seventh doped region 241G can range from 1e16cm -3 ~1e18cm -3 .

[0124] In some embodiments, the doping ion longitudinal distribution of the first doped region 231A can be consistent with the doping ion longitudinal distribution of the fifth doped region 241E. The doping ion longitudinal distribution of the second doped region 231B is consistent with the doping ion longitudinal distribution of the sixth doped region 241F. The doping ion longitudinal distribution of the fourth doped region 231D is consistent with the doping ion longitudinal distribution of the seventh doped region 241G.

[0125] For example, the doping ion concentration between the doped regions is the same, the doping ion depth is the same, the doping ion region size is the same, the doping ion type is the same, or the relative position of the doping ion region is the same, etc.

[0126] In some embodiments, the doping ion lateral distribution of the first photodiode 231 and the second photodiode 241 can also be consistent. For example, the doping ion longitudinal distribution of the first doped region 231A can be consistent with the doping ion longitudinal distribution of the fifth doped region 241E. The doping ion longitudinal distribution of the second doped region 231B is consistent with the doping ion longitudinal distribution of the sixth doped region 241F. The doping ion longitudinal distribution of the fourth doped region 231D is consistent with the doping ion longitudinal distribution of the seventh doped region 241G.

[0127] In some embodiments, the doping ion lateral distribution of the first photodiode 231 and the second photodiode 241 is not consistent. For example, the lateral area of the doping ion region in the second photodiode 241 is larger to increase the upper limit of the current passing through. For example, during the manufacturing of the second photodiode 241, the mask area used during the manufacturing of the first photodiode 231 is changed. Thus, by increasing the ion doping region of the second photodiode 241, the upper limit of the passing current of the second photodiode 241 is increased. Because it is an ESD protection device based on the original device, the process design and manufacturing cost increase less.

[0128] As shown in FIG. 4 and FIG. 8, the second photodiode 241 can be obtained by omitting the third doped region 231C from the structure of the first photodiode 231. For example, since photodiodes are usually formed by multiple ion implantation steps, the third doped region 231C can be omitted by shielding the ion implantation step of the third doped region 231C in the first photodiode 231, thereby obtaining the second photodiode. This method can achieve a suitable ESD protection working voltage based on the PD structure originally present in the chip by shielding some ion implantation steps through layout modification, which is equivalent to developing a customized ESD protection device. Moreover, no additional process steps are required, and no manufacturing costs are increased.

[0129] In some embodiments, when manufacturing the second photodiode 241, the ion implantation step of the third doped region 231C is not shielded, and the second photodiode 241 is obtained by reducing the doping ion concentration of the third doped region 231C. The breakdown voltage of the second photodiode 241 is also greater than the first breakdown voltage of the first photodiode 231.

[0130] FIG. 9 shows a structural example diagram of a second photodiode, consistent with some embodiments of the present disclosure. Referring to FIG. 9, the second photodiode 241 can include a fifth doped region 241E, a seventh doped region 241G, and an eighth doped region 241H. The seventh doped region 241G is formed above the eighth doped region 241H, that is, the eighth doped region 241H is away from one side of the substrate 210.

[0131] In some embodiments, the doping ion types of the fifth doped region 241E and the seventh doped region 241G can be different, and the doping ion types of the seventh doped region 241G and the eighth doped region 241H can be different. The doping ion types of the fifth doped region 241E and the eighth doped region 241H can be the same. For example, the conductive types of the fifth doped region 241E and the eighth doped region 241H can be P-type, the conductive type of the seventh doped region 241G can be N-type, the fifth doped region 241E can be connected to an anode, and the seventh doped region 241G can be connected to a cathode. For another example, the conductive types of the fifth doped region 241E and the eighth doped region 241H can be N-type, the conductive type of the seventh doped region can be P-type, the fifth doped region 241E can be connected to a cathode, and the seventh doped region 241G can be connected to an anode. In some embodiments, the substrate 210 can also be connected to an electrode. Details are not described herein.

[0132] Since the doping ion types of the seventh doping region 241G and the eighth doping region 241H are different, the at least partial seventh doping region 241G and the at least partial eighth doping region 241H can form a second depletion region R2. As mentioned above, the second photodiode 241 includes a vertical conduction structure. The vertical conduction structure can include a second depletion layer R2 formed in the longitudinal direction of the second photodiode. The second depletion region R2 can have a second breakdown voltage. At the second breakdown voltage, the PN junction corresponding to the second depletion region R2 can be broken down, and the second photodiode 241 can be broken down. The aforementioned first depletion region R1 has a first breakdown voltage. The first breakdown voltage can be less than the second breakdown voltage. This makes the second photodiode 241 have the characteristics of a high on-voltage and a low on-resistance. By providing only one or a small number of second photodiodes 241 in the protection circuit 240, the normal operation of the working circuit 230 can be ensured, and a low-impedance path can be provided for the instantaneous large current of ESD. This can make the protection circuit 240 occupy a smaller area on the chip, without increasing the area cost too much, and can improve the integration and yield of the chip.

[0133] In some embodiments, the doping ion longitudinal distribution of the first doping region 231A can be consistent with the doping ion longitudinal distribution of the fifth doping region 241E. For example, the doping ion concentration, the doping ion depth, the doping ion region size, the doping ion type, or the relative position of the doping ion region of the first doping region 231A and the fifth doping region 241E are the same, etc. In some embodiments, the seventh doping region 241G can be greater than the fourth doping region 231D, and the eighth doping region 241H can be less than the third doping region 231C. For example, the doping ion concentration, the doping ion depth, and the doping ion type of the seventh doping region 241G and the fourth doping region 231D are the same. However, the doping ion region size and the relative position of the doping ion region of the seventh doping region 241G and the fourth doping region 231D are different. The fourth doping region 231D is located around the third doping region 231C, and the seventh doping region 241G is located above the eighth doping region 241H and covers the position corresponding to the second doping region 231B in the first photodiode 231. Similarly, the doping ion concentration, the doping ion type, the relative position of the doping ion region, or the doping ion depth of the eighth doping region 241H and the third doping region 231C are the same. However, the doping ion region size and the doping ion depth of the eighth doping region 241H and the third doping region 231C are different. The doping ion region of the eighth doping region 241H is smaller than the doping ion region of the third doping region 231C.

[0134] In some embodiments, the size of the doping ion region can be changed by changing the mask plate.

[0135] In some embodiments, the dopant ion lateral profile of the first photodiode 231 and the second photodiode 241 can also be consistent. The dopant ion lateral profile of the first doped region 231A can be consistent with the dopant ion lateral profile of the fifth doped region 241E. For example, the process manufacturing step of the fifth doped region 241E is exactly the same as the process step of the first doped region 231A.

[0136] In some embodiments, the dopant ion lateral profile of the first photodiode 231 and the second photodiode 241 can not be consistent. For example, the lateral area of the dopant ion region in the second photodiode 241 is larger to increase the upper limit of the current passing through. For example, the mask area used in manufacturing the first photodiode 231 is modified in manufacturing the second photodiode 241. Thus, by increasing the ion doping region of the second photodiode 241, the upper limit of the passing current of the second photodiode 241 is increased. Since the ESD protection device is obtained on the basis of the original device, the process design and manufacturing cost increase less.

[0137] The dopant ion concentration of the different doped regions can be the same or different. In some embodiments, the dopant ion concentration of the eighth doped region 241H can be greater than the dopant ion concentration of the seventh doped region 241G. In some embodiments, the dopant ion concentration of the fifth doped region 241E can be greater than the dopant ion concentration of the seventh doped region 241G.

[0138] As mentioned before, the dopant ion concentration of the first photodiode 231 and the second photodiode 241 can be the same. Thus, in some embodiments, the dopant ion concentration range of the fifth doped region 241E can include 5e16cm -3 ~1e18cm -3 . The dopant ion concentration range of the seventh doped region 241G can include 1e16cm - 3 ~1e18cm -3 . The dopant ion concentration range of the eighth doped region 241H can include 5e16cm -3 ~1e18cm -3 .

[0139] As mentioned above, the first breakdown voltage of the first photodiode 231 is mainly determined by the second doped region 231B and the third doped region 231C. The second breakdown voltage of the second photodiode 241 is mainly determined by the seventh doped region 241G or the eighth doped region 241H. Since the seventh doped region 241G has a lower doping ion concentration than the second doped region 231B, and the eighth doped region 241H has the same doping ion concentration as the third doped region 231C, the corresponding breakdown voltage of the second depletion region R2 is greater than the corresponding breakdown voltage of the first depletion region R1. In this way, the photodiode 241 with a greater breakdown voltage can be manufactured, and the protection circuit 240 with a high on-voltage can be obtained using a small number of photodiodes 241. Thus, the protection circuit 240 occupies a smaller area on the chip, does not increase the area cost too much, and can improve the integration and yield of the chip.

[0140] As shown in FIG. 4 and FIG. 9, the second photodiode 241 can be obtained by removing the second doped region 231B of the first photodiode 231 and adding the fourth doped region 231D. For example, since the photodiode is usually formed by multiple ion implantation, the third doped region 231C can be removed by shielding the ion implantation step of the second doped region 231B in the first photodiode 231. Then, the second photodiode can be obtained by increasing the ion implantation area of the fourth doped region 231D. This method can be based on the PD structure that already exists in the chip, and by shielding and modifying some ion implantation steps on the layout, a suitable ESD protection working voltage can be achieved, which is equivalent to developing a customized ESD protection device. Moreover, no additional process steps are required, and the manufacturing cost is not increased.

[0141] In some embodiments, when manufacturing the second photodiode 241, the ion implantation step of the second doped region 231B is not shielded, and the second photodiode 241 is obtained by reducing the doping ion concentration of the second doped region 231B. The breakdown voltage of the second photodiode 241 is also greater than the first breakdown voltage of the first photodiode 231.

[0142] In some embodiments, the number of second photodiodes 241 is less than the number of first photodiodes 231. For example, the number of first photodiodes 231 is 3, and the number of second photodiodes 241 is 1. The area occupied by the protection circuit 240 on the substrate 210 is smaller than the area occupied by the working circuit 230 on the substrate 210. For example, by using the second photodiode 241 with a higher breakdown voltage, a small number of second photodiodes 241 can make the protection circuit 240 have a greater on-voltage. Thus, the protection circuit occupies a smaller area on the chip, does not increase the area cost too much, and can improve the integration and yield of the chip.

[0143] In some embodiments, the protection circuit 240 can include multiple branches. This can increase the upper limit of the current passing through the protection circuit 240. For example, the protection circuit can include 2, 3, 4, 5, or the like, branches. FIG. 10 shows an example diagram of the structure of a protection circuit consistent with some embodiments of the present disclosure. FIG. 19 shows an example diagram of the structure of a protection circuit consistent with some embodiments of the present disclosure. Referring to FIG. 10 and FIG. 19, the protection circuit 240 can include a first protection circuit 245, and a second protection circuit 247 in parallel with the first protection circuit 245. For example, the first protection circuit 245 can have the same or similar structure as the protection circuit 240 in any of the foregoing embodiments. For example, the second protection circuit 247 can have the same or similar structure as the protection circuit 240 in any of the foregoing embodiments.

[0144] The first protection circuit 245 can include the second photodiode 241 described above. For example, the first protection circuit 245 can include one or more second photodiodes 241. The second protection circuit 247 can include a third photodiode 243. For example, the second protection circuit 247 can include one or more third photodiodes 243. For example, the third photodiode 243 can have the same or similar structure and performance as the second photodiode 241. In some embodiments, the doping ions of the second photodiode 241 and the third photodiode 243 are longitudinally consistent. In some embodiments, the second photodiode 241 and the third photodiode 233 are the same photodiode. In some embodiments, the second photodiode 241 and the third photodiode 243 are both the same photodiode as the first photodiode 231 in terms of physical structure. In some embodiments, the second photodiode 241 is the same photodiode as the first photodiode 231 in terms of physical structure. The doping ions of the third photodiode 243 and the first photodiode 231 are not consistent in lateral distribution. In some embodiments, the doping ions of the second photodiode 241 and the third photodiode 243 are not consistent in longitudinal distribution. For example, the second photodiode 241 has the structure of the photodiode shown in FIG. 8. The third photodiode 243 has the structure of the photodiode shown in FIG. 9. For the structure and performance of the third photodiode 243, please refer to the description of the second photodiode 241 above. The present disclosure will not be repeated here.

[0145] The impedance of the first protection circuit 245 after being turned on is smaller than the impedance of the working circuit 230 after being turned on. The impedance of the second protection circuit 247 after being turned on is also smaller than the impedance of the working circuit 230 after being turned on. Both the first protection circuit 245 and the second protection circuit 247 can provide a low-impedance conduction path for the transient large current. This will make the transient large current be shunted more to the two protection circuits 240, and at the same time, clamp the high voltage generated by the ESD in a lower voltage range.

[0146] The circuit structures of the first protection circuit 245 and the second protection circuit 247 can be the same or different. In some embodiments, the circuit structures of the first protection circuit 245 and the second protection circuit 247 are the same. For example, referring to FIG. 10, the first protection circuit 245 includes one second photodiode 241 that is reversely biased; the second protection circuit 247 also includes one third photodiode 243 that is reversely biased. For another example, the first protection circuit 245 includes two second photodiodes 241 that are reversely biased; the second protection circuit 247 also includes two third photodiodes 243 that are reversely biased. In some embodiments, the circuit structures of the first protection circuit 245 and the second protection circuit 247 are different. For example, the first protection circuit 245 includes one second photodiode 241 that is reversely biased; the second protection circuit 247 includes two third photodiodes 243 that are reversely biased. For another example, referring to FIG. 19, the first protection circuit 245 includes three second photodiodes 241 that are reversely biased; the second protection circuit 247 includes two third photodiodes 243 that are reversely biased. For another example, the first protection circuit 245 includes three second photodiodes 241 that are reversely biased, and the second protection circuit 247 includes two third photodiodes 243 that are reversely biased and fifteen third photodiodes 243 that are forwardly biased. Although the turn-on voltage of the second protection circuit 247 is slightly larger than that of the first protection circuit 245, when the electrostatic voltage is very large, both the protection circuits 240 can be turned on. Thus, both the first protection circuit 245 and the second protection circuit 247 can protect the working circuit 230.

[0147] In some embodiments, the protection circuit 240 can include more branches. For example, the protection circuit 240 further includes a third protection circuit, a fourth protection circuit, and the like. The structures of the different branches of the protection circuit 240 can be the same or different.

[0148] By setting multiple protection circuits, multiple low-impedance conduction paths can be provided for the transient large current, thereby improving the upper limit of the current that the protection circuit can flow. By setting multiple protection circuits, the transient large current can be shunted more to the protection circuit, thereby providing more reliable protection for the working circuit.

[0149] The chip 200 can also include other circuit structures. In some embodiments, the chip 200 can also include a control circuit and a readout circuit. The control circuit can be configured to provide stable bias voltage, perform temperature compensation and gain control to improve the reliability of the detection performance of the lidar 10. The readout circuit can read the output signal of the first photodiode 231. There is a connection relationship between the working circuit 230, the control circuit, the readout circuit and the quenching circuit.

[0150] In some embodiments, the working circuit 230 can include a quenching circuit 233. The quenching circuit 233 is part of the working circuit 230 and is also connected in parallel with the protection circuit 240. The protection circuit 240 can protect the quenching circuit 233. For example, in a SiPM chip, the working circuit 230 includes a photodiode and a quenching resistor. In a SiPM chip, the control circuit and the readout circuit are not directly connected in parallel with the protection circuit 240. For example, the readout circuit and the control circuit are not integrated in the SiPM chip itself, but are designed outside the SiPM chip. For another example, a port is introduced between the photodiode and the quenching circuit, and the port is used to read data.

[0151] FIG. 11 shows a structural example diagram of a circuit consistent with some embodiments of the present disclosure. Referring to FIG. 11, the chip 200 can include a readout circuit 270. One end of the readout circuit 270 is electrically connected between the first photodiode 231 and the quenching circuit 233. In an optional example, the chip 200 can include one readout circuit 270, and multiple first photodiodes 231 can share one readout circuit 270. The chip 200 can also include multiple readout circuits 270, and one readout circuit 270 can be electrically connected to the corresponding first photodiode 231.

[0152] In some embodiments, the quenching circuit is not connected in parallel with the protection circuit 240. In order to distinguish from the quenching circuit 233 described above, the quenching circuit is taken as an independent circuit part, and is marked as quenching circuit 250. FIG. 12 shows a structural example diagram of a circuit consistent with some embodiments of the present disclosure. Referring to FIG. 12, in addition to the working circuit 230 and the protection circuit 240, the chip 200 further includes the quenching circuit 250. The quenching circuit 250 can restore the bias voltage of the first photodiode 231 after the first photodiode 231 occurs avalanche effect. The quenching circuit 250 can reduce the voltage across the first photodiode 231, so that it cannot continue to occur avalanche. For example, in a SPAD chip, the chip 200 includes the working circuit 230, the protection circuit 240 and the quenching circuit 250. In some embodiments, the quenching circuit 250 can include a quenching resistor. In some embodiments, the quenching circuit 250 can include a metal-oxide semiconductor field effect (MOS) tube. The MOS tube can use its voltage control function to quickly reduce the reverse bias voltage of the APD when the avalanche occurs, achieve rapid quenching, and thus reduce the recovery time of the device.

[0153] Referring to FIG. 12, a first end 250A of the quenching circuit 250 can be connected with one end of the working circuit 230, and the first end 250A of the quenching circuit 250 can be connected with one end of the protection circuit 240. The quenching circuit 250 is not connected in parallel with the protection circuit 240. The protection circuit 240 is only connected in parallel with the working circuit 230, and only provides electrostatic protection for the first photodiode 231.

[0154] In some embodiments, referring to FIG. 12, the chip 200 can further include a readout circuit 270 and a control circuit 290. The working circuit 230, the protection circuit 240, the quenching circuit 250, the readout circuit 270 and the control circuit 290 can all be integrated in the epitaxial layer 220. As an example, a connection relationship of the working circuit 230, the quenching circuit 250, the readout circuit 270 and the control circuit 290 is shown in FIG. 12. A plurality of first photodiodes 231 are connected in series with a plurality of quenching circuits 250. For example, one first photodiode 231 is connected in series with one quenching circuit 250. The plurality of quenching circuits 250 are also electrically connected with a plurality of readout circuits 270. The plurality of quenching circuits 250 are electrically connected with one control circuit 290. One end of the control circuit 290 is electrically connected with the plurality of quenching circuits 250, and the other end can receive a voltage Power, so as to drive the chip 200 to work.

[0155] FIG. 13 shows a structural example diagram of a circuit consistent with some embodiments of the present disclosure. The connection relationship of another working circuit 230, quenching circuit 250, readout circuit 270 and control circuit 290 is shown in FIG. 13. Please refer to FIG. 13, one end of the plurality of quenching circuits 250 is electrically connected with one readout circuit 270. The other end of the plurality of first photodiodes 231 is connected in series with the plurality of quenching circuits 250. The plurality of quenching circuits 250 is electrically connected with one control circuit 290. One end of the control circuit 290 is electrically connected with the plurality of quenching circuits 250, and the other end can receive a voltage Power, thereby driving the chip 200 to work.

[0156] FIG. 14 shows a structural example diagram of a circuit consistent with some embodiments of the present disclosure. The connection relationship of another working circuit 230, quenching circuit 250, readout circuit 270 and control circuit 290 is shown in FIG. 14. Please refer to FIG. 14, the plurality of first photodiodes 231 is respectively connected in series with the plurality of quenching circuits 250. The plurality of quenching circuits 250 is electrically connected with one readout circuit 270. The readout circuit 270 is connected in series with the control circuit 290. One end of the control circuit 290 is electrically connected with the readout circuit 270, and the other end can receive a voltage Power, thereby driving the chip 200 to work.

[0157] In some embodiments, the quenching circuit 250, the readout circuit 270 and the control circuit 290 can not be connected in parallel with the protection circuit 240. In some embodiments, at least one of the quenching circuit 250, the readout circuit 270 or the control circuit 290 can be connected in parallel with the protection circuit 240. The quenching circuit 250, the readout circuit 270 and the control circuit 290 shown in FIG. 14 are taken as an example for introduction.

[0158] FIG. 15 shows a structural example diagram of a circuit consistent with some embodiments of the present disclosure. Please refer to FIG. 15, the working circuit 230 and the quenching circuit 250 can be connected in parallel with the protection circuit 240. The protection circuit 240 can protect the working circuit 230 and the quenching circuit 250 at the same time.

[0159] FIG. 16 shows a structural example diagram of a circuit consistent with some embodiments of the present disclosure. Please refer to FIG. 16, the working circuit 230, the quenching circuit 250 and the readout circuit 270 can be connected in parallel with the protection circuit 240. The protection circuit 240 can protect the working circuit 230, the quenching circuit 250 and the readout circuit 270 at the same time.

[0160] FIG. 17 shows a structural example diagram of a circuit, consistent with some embodiments of the present disclosure. Referring to FIG. 17, the working circuit 230, the quenching circuit 250, the readout circuit 270, and the control circuit 290 can all be in parallel with the protection circuit 240. The protection circuit 240 can protect the working circuit 230, the quenching circuit 250, the readout circuit 270, and the control circuit 290 at the same time.

[0161] The present disclosure also provides a laser radar 10. The laser radar 10 includes a laser 100 and a chip 200 for laser detection. The laser 100 is configured to emit laser when working. The chip 200 for laser detection is configured to receive echo corresponding to the laser when working. The chip 200 for laser detection can be the chip 200 provided in any of the embodiments of FIGS. 1-17.

[0162] The present disclosure also provides a laser radar 10. The laser radar 10 includes a laser 100 and a circuit 300 for laser detection. The laser 100 is configured to emit laser when working. The circuit 300 for laser detection is configured to receive echo corresponding to the laser when working. The circuit 300 for laser detection can be the circuit 300 provided in any of the embodiments.

[0163] The present disclosure also provides a carrier 30. FIG. 18 shows a structural example diagram of a carrier, consistent with some embodiments of the present disclosure. Referring to FIG. 18, the carrier 30 includes a laser radar 10 and a connector 40. The connector 40 is configured to connect the laser radar 10 and the carrier 30.

[0164] The laser radar 10 can be the laser radar 10 provided in the embodiments of FIG. 1. In some embodiments, the carrier 30 can be a vehicle. For example, the carrier 30 can be a car, an airplane, or a ship, etc. In some embodiments, the carrier 30 can also be a smart machine. For example, the carrier 30 can be a sweeping robot or a food delivery robot, etc. The present disclosure is not limited here.

[0165] The connector 40 is configured to connect the lidar 10 and the vehicle 30. In some embodiments, the connector 40 is a snap-in slot structure. The snap-in is provided on one of the lidar 10 or the vehicle 30. The slot that fits the snap-in is provided on the other of the lidar 10 or the vehicle 30. The lidar 10 can be fixed on the vehicle 30 by the snap-in and slot mating. In some embodiments, the connector 40 is a magnetic assembly. The magnetic assembly can be provided on the lidar 10 or the vehicle 30. The lidar 10 can be fixed on the vehicle 30 by the magnetic attraction. In some embodiments, the lidar 10 can be fixed or detachably mounted on the roof of the vehicle 30 by the connector 40. In some embodiments, the lidar 10 can be fixed or detachably mounted on the rear side of the windshield of the vehicle 30 by the connector 40.

[0166] The present disclosure also provides a photodiode. The photodiode can include a substrate, an epitaxial layer, a first doped region, a second doped region, and a third doped region. The epitaxial layer is formed above the substrate. The first doped region is formed in the epitaxial layer. The second doped region is formed in the epitaxial layer and has a different type of doping ions than the first doped region. The third doped region is formed between the first doped region and the second doped region, and has the same type of doping ions as the sixth doped region. The second doped region has a higher concentration of doping ions than the third doped region, and at least part of the second doped region and at least part of the epitaxial layer form a depletion region; or at least part of the second doped region, at least part of the epitaxial layer, and at least part of the substrate form a depletion region; or at least part of the epitaxial layer and at least part of the substrate form a depletion region.

[0167] In some embodiments, the first doped region has a higher concentration of doping ions than the third doped region.

[0168] In some embodiments, the first doped region has a P-type conductivity, and the second doped region and the third doped region have an N-type conductivity. The first doped region is configured to connect an anode, and the second doped region is configured to connect a cathode.

[0169] In some embodiments, the first doped region has an N-type conductivity, and the second doped region and the third doped region have a P-type conductivity. The first doped region is configured to connect a cathode, and the second doped region is configured to connect an anode.

[0170] In some embodiments, the first doped region has a doping ion concentration in a range of 5e16cm -3 to 1e18cm -3 ; the second doped region has a doping ion concentration in a range of 1e17cm -3 to 5e18cm -3 ; and the third doped region has a doping ion concentration in a range of 1e16cm -3 to 1e18cm-3 .

[0171] In some embodiments, the photodiode can be the second photodiode 241 as previously described. In some embodiments, the first doped region of the photodiode can be the fifth doped region 241E provided in the corresponding embodiments of FIG. 8 as previously described. The second doped region can be the sixth doped region 241F provided in the corresponding embodiments of FIG. 8 as previously described, and the third doped region can be the seventh doped region 241G provided in the corresponding embodiments of FIG. 8 as previously described. The depletion region formed by the second doped region and the third doped region can be the second depletion region R2 provided in the corresponding embodiments of FIG. 8 as previously described.

[0172] The present disclosure also provides another photodiode. The photodiode includes a substrate, an epitaxial layer, a first doped region, a second doped region, and a third doped region. The epitaxial layer is formed over the substrate. The first doped region is formed in the epitaxial layer. The second doped region is formed in the epitaxial layer and has a different doping ion type from the first doped region. The third doped region is formed under the second doped region and has a different doping ion type from the second doped region. The third doped region has a doping ion concentration greater than a doping ion concentration of the second doped region. At least the second doped region and the third doped region form a depletion region.

[0173] In some embodiments, the first doped region has a doping ion concentration greater than a doping ion concentration of the second doped region.

[0174] In some embodiments, the first doped region and the third doped region have a P-type conductivity, and the second doped region has an N-type conductivity. The first doped region is configured to connect to an anode, and the second doped region is configured to connect to a cathode.

[0175] In some embodiments, the first doped region and the third doped region have an N-type conductivity, and the second doped region has a P-type conductivity. The first doped region is configured to connect to a cathode, and the second doped region is configured to connect to an anode.

[0176] In some embodiments, the first doped region can have a doping ion concentration ranging from 5e16cm -3 to 1e18cm -3 , the second doped region can have a doping ion concentration ranging from 1e16cm -3 to 1e18cm -3 , and the third doped region can have a doping ion concentration ranging from 5e16cm -3 to 1e18cm -3 .

[0177] In some embodiments, the photodiode can be the second photodiode 241 as previously described. In some embodiments, the first doped region of the photodiode can be the fifth doped region 241E provided in the corresponding embodiment of FIG. 9 as previously described. The second doped region can be the seventh doped region 241G provided in the corresponding embodiment of FIG. 8 as previously described, and the third doped region can be the ninth doped region 241H provided in the corresponding embodiment of FIG. 8 as previously described. The depletion region formed by the second doped region and the third doped region can be the second depletion region R2 provided in the corresponding embodiment of FIG. 9 as previously described.

[0178] In summary, the chip road 200 provided by the present disclosure can reduce the damage of ESD to the working circuit 230 by setting the protection circuit 240 with high conduction voltage and low conduction impedance. Specifically, since the conduction voltage of the protection circuit 240 is higher than the working voltage, the protection circuit 240 is not turned on when the working circuit 230 is working. In this way, the protection circuit 240 will not affect the normal work of the working circuit 230 when the working circuit 230 is working. When the ESD phenomenon occurs, the static voltage will be applied to the protection circuit 240 at the same time. The higher static voltage makes the protection circuit 240 be turned on. Since the impedance of the protection circuit 240 after being turned on is smaller than the impedance of the working circuit 230 after being turned on, the protection circuit 240 can provide a low-impedance conduction path for the instantaneous large current. This will make the instantaneous large current be shunted to the protection circuit 240 more, and the voltage across the working circuit 230 is clamped in a lower voltage range. By setting the protection circuit 240 with high conduction voltage and low impedance, the damage of ESD to the working circuit 230 can be reduced. The second photodiode 241 has a vertical conduction structure, thereby having stronger current conduction capability. And the second photodiode 241 or chip area occupation has more advantages, and the area occupation is less. On the basis of the process steps of the first photodiode, by changing the longitudinal distribution of the doping ions of the second photodiode, the longitudinal distribution of the doping ions of the first photodiode 231 and the second photodiode 241 can be different. Thus, the second photodiode 241 can have a higher breakdown voltage in the longitudinal direction. In this way, by setting only one or a few second photodiodes 241 in the protection circuit 240, the normal work of the working circuit 230 can be ensured, and a low-impedance path can be provided for the instantaneous large current of ESD. This can make the protection circuit 240 occupy a smaller area on the chip, without increasing too much area cost, and can improve the integration and yield of the chip.

[0179] The above describes particular embodiments of the present disclosure. Other embodiments are within the scope of the following claims. In some cases, the actions or steps recited in the claims can be performed in a different order and still accomplish desirable results. Additionally, the processes depicted in the figures do not necessarily require the particular order shown, or sequential order to achieve desirable results. In certain implementations, multitasking and parallel processing can be advantageous.

[0180] In light of the above, it should be appreciated that the foregoing detailed description and specific examples of the present disclosure are presented for purposes of clarity and explanation only. The description and examples are not intended to limit the scope of the disclosure, which is defined by the claims. Although specific examples of the disclosure are described in this disclosure, many decisions regarding specific embodiments can be made by a person of skill in the art, and such decisions are intended to be within the scope of the present disclosure. Such alterations, modifications, and improvements as are made to the above-described processes, methods, and apparatus are intended to be part of this disclosure.

[0181] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The description and drawings are illustrative of the disclosure and are not to be construed as limiting the disclosure. The terms "comprising," "having," "including," and "containing" as used herein are meant to be interpreted in a non-limiting manner. In the description of embodiments of the disclosure, the terms "first", "second", and so on are used to distinguish one element from another, and are not necessarily used to describe a particular sequential order or priority. In the description of embodiments of the disclosure, the term "a plurality" means two or more, unless otherwise specifically indicated.

[0182] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the disclosure. The appearances of the phrase "in an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily all directed to the other embodiments. It is explicitly contemplated that embodiments described herein can be combined with each other.

[0183] The features and other details of the present disclosure, as well as the operation and function of the related elements of structure and the combination of parts and economies of manufacture, can be more clearly understood and appreciated from the following description, and from the drawings. Reference will now be made to the drawings wherein:

[0184] The flowcharts used in the present disclosure show the operations implemented by the system according to some embodiments in the present disclosure. It should be clearly understood that the operations of the flowcharts can not be implemented in sequence. Instead, the operations can be implemented in reverse order or simultaneously. In addition, one or more other operations can be added to the flowcharts. One or more operations can be removed from the flowcharts.

[0185] In the present disclosure, "X includes at least one of A, B, or C" means that X includes at least A, or X includes at least B, or X includes at least C. That is, X can include only A, B, or C, or any combination of A, B, and C, and other possible contents or elements. The combination of A, B, and C can be A, B, C, AB, AC, BC, or ABC.

[0186] In the present disclosure, "or" and "and / or" describe the association relationship between the associated objects, and represent a non-exclusive inclusion. For example, each of "A and / or B" and "A or B" can include: only "A" exists, only "B" exists, and both "A" and "B" exist. Wherein, "A" and "B" can be singular or plural. For another example, each of "A, B, and / or C" and "A, B, or C" can include: only "A" exists, only "B" exists, only "C" exists, both "A" and "B" exist, both "A" and "C" exist, both "B" and "C" exist, and both "A", "B", and "C" exist. Wherein, "A", "B", and "C" can be singular or plural.

[0187] In the present disclosure, "X includes at least one of A, B, or C" means that X includes at least A, or X includes at least B, or X includes at least C. That is, X can include only A, B, or C, or any combination of A, B, and C, and other possible contents or elements. The combination of A, B, and C can be A, B, C, AB, AC, BC, or ABC.

[0188] In the present disclosure, unless specifically stated, the association relationship generated between the structures can be a direct association relationship or an indirect association relationship. For example, when describing "A is connected with B", unless it is specifically stated that A is directly connected with B, it should be understood that A can be directly connected with B or indirectly connected with B. For another example, when describing "A is on B", unless it is specifically stated that A is directly on B (AB is adjacent and A is on B), it should be understood that A can be directly on B or indirectly on B (there are other elements between AB and A is on B). By analogy, when describing "A is in B", unless it is specifically stated that A is completely inside B, it should be understood that all of A can be inside B or part of A can be inside B.

[0189] In addition, the terms "mount", "set", "provided with", "connected", "linked" should be interpreted broadly. For example, it can be fixed connection, detachable connection, or integral structure; can be mechanical connection, or electrical connection; can be direct connection, or indirect connection through intermediate medium, or internal communication between two devices, elements or components. The specific meaning of the above terms in the present application can be understood by the person skilled in the art according to the specific circumstances. The present disclosure will be described in detail below.

[0190] In addition, certain terms have been used in the present disclosure to describe embodiments of the present disclosure. For example, "one embodiment", "embodiment" and / or "some embodiments" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present disclosure. Therefore, it can be emphasized and should be understood that two or more references to "embodiments" or "one embodiment" or "alternative embodiments" in various parts of the present disclosure do not necessarily all refer to the same embodiment. In addition, particular features, structures, or characteristics can be appropriately combined in one or more embodiments of the present disclosure.

[0191] It should be understood that in the foregoing description of embodiments of the present disclosure, for the purpose of helping to understand one feature, the present disclosure combines various features in a single embodiment, figure or its description for the purpose of simplifying the present disclosure. However, this does not mean that the combination of these features is necessary, and a person skilled in the art can well mark out part of the device as a separate embodiment when reading the present disclosure. That is, the embodiments in the present disclosure can also be understood as the integration of multiple secondary embodiments. And the content of each secondary embodiment is also valid when there are less than all the features of a single previously disclosed embodiment.

[0192] Each patent, patent application, publication of patent application, and other material, such as articles, books, specifications, publications, documents, items, etc., cited in this document are hereby incorporated by reference in their entirety for all purposes to the same extent as if each individual item were specifically and individually indicated to be incorporated by reference herein for its entirety for all purposes. In addition, if there is any inconsistency between the description, definition and / or use of terms associated with any of the incorporated materials and the terms, description, definition and / or used in this document, the terms in this document shall prevail.

[0193] Finally, it should be understood that the embodiments disclosed herein are illustrative of the principles of the embodiments of this disclosure. Other modified embodiments are also within the scope of this disclosure. Therefore, the embodiments disclosed herein are merely examples and not limitations. Those skilled in the art can implement the applications of this disclosure using alternative configurations based on the embodiments in this disclosure. Therefore, the embodiments of this disclosure are not limited to the embodiments precisely described in the applications.

Claims

1. A chip for laser probing, characterized by The chip comprises: a substrate; an epitaxial layer formed above the substrate; a working circuit formed in the epitaxial layer, comprising a first photodiode configured to detect incident laser at a working voltage; and a protection circuit formed in the epitaxial layer in parallel with the working circuit, comprising a second photodiode; wherein the on voltage of the protection circuit is greater than the working voltage, and the impedance of the protection circuit after being turned on is less than the impedance of the working circuit after being turned on. The first photodiode comprises a first doped region, a second doped region, and a third doped region; wherein 2. The chip of claim 1, wherein the first doped region and the second doped region are different in doped ion type; the second doped region is formed above the third doped region, the second doped region and the third doped region are different in doped ion type, and at least part of the second doped region and at least part of the third doped region form a first depletion region. The first photodiode further comprises a fourth doped region; wherein 3. The chip of claim 2, wherein the fourth doped region is formed between the first doped region and the second doped region, the second doped region is greater in doped ion concentration than the fourth doped region, the third doped region is greater in doped ion concentration than the fourth doped region, and the second doped region and the fourth doped region are the same in doped ion type.

4. The chip according to any one of claims 2 or 3, wherein the second photodiode and the first photodiode are the same in longitudinal distribution of doped ions. The first doped region has a dopant ion concentration ranging from 5e16 cm -3 ~1e18 cm -3 ; The second doped region has a dopant ion concentration ranging from 1e17 cm -3 ~5e18 cm -3 ; The third doped region has a doped ion concentration ranging from 5e16 cm -3 ~1e18 cm -3 ; and The fourth doped region has a doped ion concentration ranging from 1e16 cm -3 ~1e18 cm -3 .

5. The chip according to any one of claims 1 to 4, characterized in that, The second photodiode comprises a plurality of series-connected photodiodes, and the plurality of series-connected photodiodes comprise at least one reverse-biased photodiode.

6. The circuit of claim 1, wherein, The plurality of series-connected photodiodes comprise at least two reverse-biased photodiodes, or the plurality of series-connected photodiodes comprise one reverse-biased photodiode and a plurality of forward-biased photodiodes.

7. The circuit of claim 6, wherein, The second photodiode has a vertical conduction structure, and the first photodiode and the second photodiode are different in longitudinal distribution of doped ions.

8. The chip according to any one of claims 1 to 4, wherein, The second photodiode comprises a fifth doped region, a sixth doped region, and a seventh doped region; wherein 9. The chip of claim 8, wherein, the fifth doped region and the sixth doped region are different in doped ion type, the sixth doped region and the seventh doped region are the same in doped ion type, the seventh doped region is formed between the fifth doped region and the sixth doped region, and the sixth doped region is greater in doped ion concentration than the seventh doped region; the first depletion region has a first breakdown voltage, the substrate, the epitaxial layer, and the sixth doped region correspond to a second breakdown voltage, and the second breakdown voltage is greater than the first breakdown voltage; at least part of the sixth doped region and at least part of the epitaxial layer form a second depletion region, or at least part of the sixth doped region, at least part of the epitaxial layer, and at least part of the substrate form a second depletion region, or at least part of the epitaxial layer and at least the substrate form a second depletion region. The second photodiode comprises a fifth doped region, a seventh doped region, and an eighth doped region; wherein 10. The chip of claim 8, wherein, ​ The seventh doped region is formed above the eighth doped region, and the seventh doped region and the eighth doped region form a second depletion region; The first depletion region has a first breakdown voltage, and the second depletion region has a second breakdown voltage, and the first breakdown voltage is less than the second breakdown voltage; The eighth doped region has a doping ion concentration greater than that of the seventh doped region; the fifth doped region and the seventh doped region have different doping ion types, and the seventh doped region and the eighth doped region have different doping ion types.

11. The chip according to any one of claims 1-10, wherein, The number of the second photodiodes is less than the number of the first photodiodes; and The area occupied by the protection circuit on the substrate is less than the area occupied by the working circuit on the substrate.

12. The chip according to any one of claims 1 to 11, characterized in that The working circuit further comprises a quenching circuit; The quenching circuit is connected in series with the first photodiode; The quenching circuit is configured to restore the bias voltage of the first photodiode after the first photodiode generates avalanche effect.

13. The chip according to any one of claims 1 to 11, wherein The chip further comprises a quenching circuit; The quenching circuit is configured to restore the bias voltage of the first photodiode after the first photodiode generates avalanche effect; A first end of the quenching circuit is connected to one end of the working circuit, and the first end of the quenching circuit is connected to one end of the protection circuit.

14. A lidar, comprising: Comprising: a laser configured to emit laser light when in operation; and the chip of any one of claims 1-13 configured to receive the echo corresponding to the laser light.

15. A carrier, characterized by Comprising: the lidar of claim 14; and a connector configured to connect the lidar and the vehicle.

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