WO2022061831A1 - Diode et son procédé de fabrication, puce de réception, dispositif de mesure de distance et plateforme mobile - Google Patents

Diode et son procédé de fabrication, puce de réception, dispositif de mesure de distance et plateforme mobile Download PDF

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WO2022061831A1
WO2022061831A1 PCT/CN2020/118170 CN2020118170W WO2022061831A1 WO 2022061831 A1 WO2022061831 A1 WO 2022061831A1 CN 2020118170 W CN2020118170 W CN 2020118170W WO 2022061831 A1 WO2022061831 A1 WO 2022061831A1
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layer
ion implantation
preparation
doping
avalanche photodiode
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PCT/CN2020/118170
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English (en)
Chinese (zh)
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王国才
卢栋
郑国光
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深圳市大疆创新科技有限公司
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Priority to PCT/CN2020/118170 priority Critical patent/WO2022061831A1/fr
Priority to CN202080014793.6A priority patent/CN114556533A/zh
Publication of WO2022061831A1 publication Critical patent/WO2022061831A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/66007—Multistep manufacturing processes
    • H01L29/66075—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
    • H01L29/66083—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by variation of the electric current supplied or the electric potential applied, to one or more of the electrodes carrying the current to be rectified, amplified, oscillated or switched, e.g. two-terminal devices
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/08—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors
    • H01L31/10—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors characterised by potential barriers, e.g. phototransistors
    • H01L31/101—Devices sensitive to infrared, visible or ultraviolet radiation
    • H01L31/102—Devices sensitive to infrared, visible or ultraviolet radiation characterised by only one potential barrier
    • H01L31/107—Devices sensitive to infrared, visible or ultraviolet radiation characterised by only one potential barrier the potential barrier working in avalanche mode, e.g. avalanche photodiodes

Definitions

  • the present application generally relates to the field of integrated circuits, and more particularly, to an avalanche photodiode and a method for manufacturing the same, a receiving chip, a ranging device, and a movable platform.
  • Lidar is a radar system that emits laser beams to detect the position, velocity and other characteristic quantities of targets.
  • the photosensitive sensor of the lidar can convert the obtained optical pulse signal into an electrical signal, and obtain the time information corresponding to the electrical signal based on the comparator, thereby obtaining the distance information between the lidar and the target.
  • avalanche photodiode As a widely used photoelectric detection device, is notable for its ability to amplify the weak light signal inside the device through the photomultiplier effect, and the amplified signal can be It is recognized and collected by the post-stage circuit, so as to overcome the disadvantage that the traditional diode cannot effectively detect the weak light signal, and realize the detection of the weak light signal.
  • APD devices have a trade-off between quantum efficiency and bandwidth, or in order to achieve a trade-off between quantum efficiency and bandwidth, its fabrication process is difficult to be compatible with CMOS, which is not conducive to modern large-scale integrated fabrication.
  • a first aspect of the present application provides a preparation method of an avalanche photodiode, the preparation method comprising:
  • a first ion implantation of a first doping type is performed on the epitaxial layer to form a first doping layer, wherein the depth of the peak concentration of the first ion implantation is greater than or equal to 2 ⁇ m, and the first ion implantation
  • the dose is 1 ⁇ 1012cm-3 ⁇ 3 ⁇ 1012cm-3;
  • the first doping type and the second doping type are different, the first doping layer and the second doping layer and the first doping layer and the second doping layer The area in between constitutes the avalanche region of the avalanche photodiode.
  • a second aspect of the present application provides an avalanche photodiode, the avalanche photodiode comprising:
  • an avalanche region located in the epitaxial layer, comprising the first doped layer and the second doped layer and a region between the first doped layer and the second doped layer, wherein:
  • the first doping layer has a first doping type, the depth of the peak concentration of the first doping layer is greater than or equal to 2 ⁇ m, and the doping dose of the first doping layer is 1 ⁇ 10 12 cm -3 to 3 ⁇ 10 12 cm -3 ;
  • the second doping layer located above the first doping layer, has a second doping type, and the first doping type is different from the second doping type.
  • a third aspect of the present application provides a receiving chip, the receiving chip comprising:
  • the aforementioned avalanche photodiode is used to receive the optical pulse sequence reflected by the detected object, and convert the received optical pulse sequence into a current signal;
  • the signal processing unit is used for receiving and processing the current signal of the avalanche photodiode to output a time signal.
  • a fourth aspect of the present application provides a distance measuring device, the distance measuring device comprising:
  • Light emitting circuit for emitting light pulse sequence
  • the aforementioned receiving chip is used to receive the optical pulse sequence reflected by the detected object, and output a time signal based on the received optical pulse sequence;
  • an arithmetic circuit for calculating the distance between the detected object and the lidar according to the time signal.
  • a fifth aspect of the present application provides a movable platform, the movable platform includes:
  • the distance measuring device is provided on the movable platform body.
  • the present application provides an avalanche photodiode and a preparation method thereof, a receiving chip, a ranging device, and a movable platform.
  • the depth of the peak concentration of the first ion implantation in the first doping layer is greater than or equal to 2 ⁇ m, and the first ion implantation has a depth of 2 ⁇ m or more.
  • the implanted dose is 1 ⁇ 10 12 cm -3 to 3 ⁇ 10 12 cm -3 .
  • the first ions increase slowly between the surface of the epitaxial layer and the peak concentration.
  • the avalanche region will be expanded accordingly, so that in the same Under the condition of breakdown voltage, the electric field strength of the avalanche region is reduced, thereby reducing the gain and noise factor of the avalanche region.
  • FIG. 1A-1L show schematic cross-sectional views of each intermediate device in the preparation process of the avalanche photodiode provided by the present application
  • FIG. 2 shows a schematic flowchart of a method for preparing an avalanche photodiode provided by the present application
  • FIG. 3 shows a schematic structural diagram of the laser ranging device described in the present application.
  • an Avalanche Photodiode is a metallurgical junction interface (PN junction) device operating in a reverse biased state. Its operating voltage is less than the junction breakdown voltage, and the device is depleted under the action of reverse bias.
  • the generated optical signal When excited by an external optical signal, the generated optical signal generates photo-generated carriers in the depletion region, and the photo-generated carriers are separated under the action of the external electric field and move to the anode and the cathode respectively. Under the action of the external electric field, the photogenerated carriers are accelerated.
  • the avalanche voltage of the N++/P junction region of the structure can be obtained by the following empirical formula:
  • the quantum efficiency is proportional to the thickness of the P region. Under the condition of a certain thickness of the P region, the larger the depletion region, the faster the photo-generated carrier transfer speed. Conversely, the inability of the depletion region to deplete the entire P region leads to the existence of a neutral body region. In the neutral body region, carriers enter the depletion region by means of a diffusion process, which takes a long time and limits the bandwidth of the APD device.
  • the gain noise factor satisfies the following formula:
  • K is the ratio of hole collision ionization coefficient to electron collision ionization coefficient. It can be seen that in order to reduce the gain noise factor, K should be reduced, and K increases with the increase of the avalanche voltage. Therefore, an effective way to reduce the gain noise factor is to use a low-doped P epitaxial layer, which can also solve the problem of quantum efficiency and bandwidth. problem, but the price is that the breakdown voltage is too high, which increases the difficulty of practical use.
  • the inventors additionally found that for the N+/P/P-/P++ type APD device structure, the trade-off between quantum efficiency, breakdown voltage and bandwidth can be achieved by using different doping concentration regions; it is also possible to adjust the doping and thickness of the P region.
  • CMOS Complementary Metal Oxide Semiconductor
  • N++/P/P+ type APD device requires a trade-off among quantum efficiency, bandwidth, gain noise factor, and breakdown voltage. It is difficult to find the optimal structure for the actual structure device to meet the above indicators.
  • the N+/P/P-/P++ type APD device structure although each different doped part can be obtained by epitaxial growth, is not compatible with CMOS, which is not conducive to modern large-scale integration preparation.
  • the present application provides a preparation method of an avalanche photodiode, characterized in that the preparation method includes:
  • a first ion implantation of a first doping type is performed on the epitaxial layer to form a first doping layer, wherein the depth of the peak concentration of the first ion implantation is greater than or equal to 2 ⁇ m, and the first ion implantation
  • the dose is 1 ⁇ 10 12 cm -3 to 3 ⁇ 10 12 cm -3 ;
  • the first doping type and the second doping type are different, the first doping layer and the second doping layer and the first doping layer and the second doping layer The area in between constitutes the avalanche region of the avalanche photodiode.
  • the present application also provides an avalanche photodiode, the avalanche photodiode includes:
  • an avalanche region located in the epitaxial layer, comprising the first doped layer and the second doped layer and a region between the first doped layer and the second doped layer, wherein:
  • the first doping layer has a first doping type, the depth of the peak concentration of the first doping layer is greater than or equal to 2 ⁇ m, and the doping dose of the doping layer is 1 ⁇ 10 12 cm ⁇ 3 ⁇ 3 ⁇ 10 12 cm -3 ;
  • the second doping layer located above the first doping layer, has a second doping type, and the first doping type is different from the second doping type.
  • the present application provides an avalanche photodiode and a preparation method thereof, a receiving chip, a ranging device, and a movable platform.
  • the depth of the peak concentration of the first ion implantation in the first doping layer is greater than or equal to 2 ⁇ m, and the first ion implantation has a depth of 2 ⁇ m or more.
  • the implanted dose is 1 ⁇ 10 12 cm -3 to 3 ⁇ 10 12 cm -3 .
  • the first ions increase slowly between the surface of the epitaxial layer and the peak concentration.
  • the avalanche region will be expanded accordingly, so that in the same Under the condition of breakdown voltage, the electric field strength of the avalanche region is reduced, thereby reducing the gain and noise factor of the avalanche region.
  • the present application also provides a preparation method of an avalanche photodiode, as shown in FIG. 2 , the preparation method specifically includes the following steps:
  • Step S1 providing a substrate formed with an epitaxial layer
  • Step S2 performing a first ion implantation of a first doping type on the epitaxial layer to form a first doping layer, wherein the depth of the peak concentration of the first ion implantation is greater than or equal to 2 ⁇ m, and the first ion implantation has a depth of 2 ⁇ m or more.
  • the dose of one ion implantation is 1 ⁇ 10 12 cm -3 to 3 ⁇ 10 12 cm -3 ;
  • Step S3 performing a second ion implantation of a second doping type on the epitaxial layer to form a second doping layer, the second doping layer being located above the first doping layer;
  • the first doping type and the second doping type are different, the first doping layer and the second doping layer and the first doping layer and the second doping layer The area in between constitutes the avalanche region of the avalanche photodiode.
  • FIGS. 1A-1L show schematic cross-sectional views of each intermediate device in the process of preparing the avalanche photodiode provided by the present application.
  • a substrate 101 having an epitaxial layer 102 is provided, wherein the substrate 101 may be at least one of the following materials: silicon, silicon-on-insulator ( SOI), silicon on insulator (SSOI), silicon germanium on insulator (S-SiGeOI), silicon germanium on insulator (SiGeOI), germanium on insulator (GeOI), etc.
  • SOI silicon-on-insulator
  • SSOI silicon on insulator
  • SiGeOI silicon germanium on insulator
  • SiGeOI silicon germanium on insulator
  • GeOI germanium on insulator
  • the substrate 101 is made of silicon.
  • the epitaxial layer 102 can be made of semiconductor material, and in an embodiment of the present application, an epitaxial silicon wafer is selected.
  • the thickness of the epitaxial layer 102 is approximately 60 ⁇ m, and the thickness of the epitaxial layer 102 is not limited to a certain value range.
  • the epitaxial layer 102 is a silicon layer with an incident wavelength of 850 nm to 940 nm.
  • the incident wavelength of the epitaxial layer is 905 nm.
  • the light absorption coefficient in the range is small to improve the light transmittance.
  • the epitaxial layer 102 includes a first surface and a second surface disposed opposite to each other, the second surface of the epitaxial layer 102 is disposed on the substrate 101, and the first surface of the epitaxial layer 102 is far away from the substrate Bottom 101.
  • the first surface is a front surface
  • the second surface is a back surface.
  • the avalanche photodiode may be a back-illuminated device or a front-illuminated device, and is not limited to any one.
  • the avalanche photodiode can be a back-illuminated device, that is, in the back-illuminated device where the photosensitive device APD is located in front of the circuit transistor, light first enters the photosensitive device APD, thereby increasing the photosensitive amount.
  • the APD is formed on the first surface of the epitaxial layer 102 , that is, the front surface of the epitaxial layer 102 , and the light is taken in from the back surface of the epitaxial layer 102 , that is, the light enters from the second surface of the epitaxial layer 102 .
  • the epitaxial layer 102 has a low doping type, and the doping type may be N-type or P-type. Generally, the epitaxial layer 102 is P-type doped.
  • setting the epitaxial layer 102 to a low-doped type can reduce the consumption of photogenerated carriers in the APD, thereby quickly reaching the avalanche collection area of the APD, and improving the corresponding speed of the APD, Avoid the tailing problem of APD and avoid the delay of the device.
  • the substrate 101 is a heavily doped substrate, and the heavily doped substrate can be used as an electrode in the subsequent steps, thereby leading out the signal of the avalanche photodiode.
  • the doping concentration of the substrate is 5 ⁇ 10 18 /cm 3 to 5 ⁇ 10 20 /cm 3 .
  • a first ion implantation of a first doping type is performed on the epitaxial layer 102 to form a first doping layer 109, as shown in FIG. 1C, in the present application, by adjusting the first doping
  • the implantation depth and dose of the layer 109 can adjust the electric field strength of the avalanche region to realize the optimization of the device gain and noise factor.
  • the method further includes the step of forming a protective layer 103 on the surface of the epitaxial layer 102 , as shown in FIG. 1A .
  • the protective layer 103 can be selected from conventional oxides, for example, silicon oxide can be selected.
  • the thickness of the protective layer 103 is 10-30 nm.
  • the protective layer 103 is formed before the ion implantation is performed to reduce the damage to the surface lattice during the ion implantation.
  • the thickness of the protective layer 103 is about 10 nm, and the thickness of the protective layer 103 is not limited to a certain value range.
  • the depth of the peak concentration of the first ion implantation is greater than or equal to 2 ⁇ m, and the dose of the first ion implantation is 1 ⁇ 10 12 cm ⁇ 3 to 3 ⁇ 10 12 cm ⁇ 3.
  • the avalanche region will be expanded accordingly, thereby reducing the electric field strength of the avalanche region under the same breakdown voltage, thereby reducing the gain and noise factor of the avalanche region.
  • the first ion implantation is P-type ion implantation.
  • the P-type ions are B ions.
  • the concentration of the first ions increases slowly between the surface of the epitaxial layer 102 and the peak concentration, that is, P++/P-- can be realized on the epitaxial layer 102 by one ion implantation. /P++ structure.
  • the energy of the first ion implantation is 1200keV ⁇ 1600keV.
  • the included angle between the direction of the first ion implantation and the plane perpendicular to the surface of the epitaxial layer 102 is 0°-10°.
  • the distribution of doping impurities after the ion implantation is controlled by controlling the direction of the first ion implantation, for example, the angle between the direction of the first ion implantation and the plane perpendicular to the surface of the epitaxial layer 102
  • the concentration of doping impurities will gradually increase after the first ion implantation, and will reach a peak value, so that the electric field distribution of the prepared avalanche photodiode is more uniform, and the absorption rate of the avalanche region is improved. higher.
  • the angle between the direction of the first ion implantation and a plane perpendicular to the surface of the epitaxial layer 102 is 0 degrees.
  • the angle between the direction of the first ion implantation and a plane perpendicular to the surface of the epitaxial layer is 7 degrees.
  • a second ion implantation of a second doping type is performed on the epitaxial layer 102 to form a second doping layer 108, and the second doping layer 108 is located in the above the first doped layer 109 .
  • the first doped layer 109 and the second doped layer 108 and the region between the first doped layer 109 and the second doped layer 108 constitute the avalanche region of the avalanche photodiode .
  • the first doping type is different from the second doping type, wherein the first ion implantation is P-type, and the second ion implantation is N-type, in an embodiment of the present application , the second ion implantation is P (phosphorus) ion or As ion.
  • the top of the epitaxial layer 102 is the second doped layer 108 , the lower part is the first doped layer 109 , and a transition region between the two, such as the first doped layer 109 .
  • the P- under the second doped layer 108, the P+ layer with increasing concentration, and the epitaxial layer 102 further form the N++/P-/P+/P++/P--/P++ structure of the avalanche photodiode.
  • an absorbing layer and the like may be further included below the avalanche region, which will not be repeated here.
  • the depth of the peak concentration of the second ion implantation is less than or equal to 200 nm, and in one embodiment of the present application, the depth of the peak concentration of the second ion implantation is 100 nm.
  • the dose of the second ion implantation is 1 ⁇ 10 14 cm ⁇ 3 to 1 ⁇ 10 15 cm ⁇ 3 ; the energy of the second ion implantation is 20keV ⁇ 100keV, so as to form the second doping layer 108 .
  • the preparation method further includes: performing a rapid annealing step, the temperature of the rapid annealing is 900 degrees Celsius to 1150 degrees Celsius, and the time is 10s to 60s, for activating the implanted ions and eliminating ion implantation defects .
  • the method further includes:
  • a guard ring 105 is formed in the epitaxial layer 102 , as shown in FIG. 1B , and in the subsequent second ion implantation step, the second ion implantation is performed in the guard ring 105 to form a
  • the second doped layer 108 (as shown in FIG. 1E ) surrounded by the guard ring 105 is formed by forming the guard ring 105 to prevent edge breakdown, thereby further improving the yield and performance of the device.
  • the step of forming the guard ring 105 may be before the first ion implantation of the first doping type, or after the first ion implantation of the first doping type and after the second doping type
  • the type of second ion implantation can be selected according to actual needs.
  • the guard ring 105 is formed before the first ion implantation of the first doping type.
  • the method for forming the guard ring 105 includes:
  • a patterned mask layer 104 is formed on the epitaxial layer 102 to expose the area where the guard ring 105 is to be formed;
  • a photoresist layer is formed on the epitaxial layer as the mask layer 107, and then the photoresist layer is exposed and developed to expose the guard ring to be formed Area.
  • a third ion implantation of the second doping type is performed using the mask layer 104 as a mask to form the guard ring 105 in the exposed region.
  • the second doping type is N-type
  • the third ion implantation is P (phosphorus) ion or As ion.
  • the third ion implantation is P (phosphorus) ions. Compared with As ions, P (phosphorus) ions have smaller ions and deeper implantation depths, and have better protection effects.
  • the third ion implantation is implemented by means of multiple ion implantation, and the multiple ion implantation can make the distribution of ions after implantation more uniform and have better protection effect.
  • the energy of the third ion implantation is 20keV ⁇ 800keV
  • the dose of the third ion implantation is 1 ⁇ 10 12 cm ⁇ 3 to 4 ⁇ 10 12 cm ⁇ 3 .
  • the depth of the guard ring 105 is greater than or equal to 2 ⁇ m.
  • low temperature annealing is performed, wherein the annealing temperature is 800-1000 degrees Celsius for 1-30 minutes to diffuse the implanted phosphorus ions in the guard ring 105 region to activate the ions and eliminate defects.
  • the annealing time is within 30min, so as to be more compatible with the CMOS process.
  • the depth of the guard ring 105 is greater than or equal to 2 ⁇ m.
  • the annealing temperature is kept below 1000 degrees Celsius, which can prevent the high-concentration doping of the substrate 101 from diffusing into the epitaxial layer 102, and avoid affecting the electric field distribution during avalanche of the epitaxial layer through diffusion, resulting in tailing of the photoresponse.
  • the mask layer 104 is removed.
  • the method for forming the guard ring 105 may further include the following steps:
  • the epitaxial layer 102 is etched to form a trench; wherein the depth of the trench is greater than or equal to 2 ⁇ m.
  • the trench is then filled to form the guard ring 105 to perform the second ion implantation within the guard ring 105 and to form the second doped layer 108 surrounded by the guard ring 105 .
  • the avalanche layer of the avalanche photodiode described in the present application can be formed through the above steps, and the electric field strength of the avalanche region can be effectively adjusted by adjusting the implantation depth and dose of the first doped layer, so as to realize the optimization of the device gain and noise factor.
  • the method further includes the step of forming the first electrode 106 .
  • the formation method of the first electrode 106 includes:
  • a mask layer is formed again on the epitaxial layer 102 to expose the region where the first electrode 106 is to be formed at the edge of the epitaxial layer 102 , and then the first doping type is performed on the exposed edge region of the epitaxial layer 102 .
  • Four ions are implanted to form the first electrode 106 outside the guard ring 105 .
  • the first electrode 106 is formed by B ion implantation for electrical connection and isolation between pixels.
  • the method further includes the step of removing the protective layer 103 .
  • the method further includes the step of forming a cut-off ring 112 , as shown in FIG. 1G , wherein the cut-off ring 112 has a thickness of generally Above 500 nm, the cut-off ring 112 with this thickness can prevent the second doped layer 108 from being pressurized below the cut-off ring 112 corresponding to the voltage region to form an inversion layer, resulting in conduction between the second doped layer 108 and the first electrode 106 .
  • cut-off ring 112 can also be used to neutralize the surface state of the epitaxial layer 102 to further prevent the conduction between the second doped layer 108 and the first electrode 106 .
  • the method for forming the cut-off ring 112 specifically includes the following steps:
  • a cut-off ring material layer is formed on the second surface of the epitaxial layer 102 to cover the epitaxial layer 102 and various devices formed on the surface thereof;
  • the stop ring material layer is then patterned to form a stop ring 112 between the guard ring 105 and the first electrode 106 .
  • the region where the cut-off ring 112 needs to be retained is defined by a photolithography process. After the photolithography is completed, the silicon oxide that does not need to be retained is removed by etching to form the cut-off ring 112 , as shown in FIG. 1G .
  • the material of the cut-off ring 112 may be silicon oxide, but is not limited to this material.
  • the method further includes the step of forming an anti-reflection layer 113 , by forming the anti-reflection layer 113 to further increase the transmittance of light, reduce the reflection of light, and further improve the device performance.
  • the anti-reflection layer 113 can be selected from silicon nitride or silicon oxide.
  • the method for forming the antireflection layer 113 includes the following steps:
  • an antireflection layer 113 is formed on the epitaxial layer 102 , wherein the antireflection layer 113 covers the epitaxial layer 102 and the devices on the surface thereof;
  • the anti-reflection layer 113 is patterned to form a first opening and expose the first electrode 106 and the second doped layer 108 for forming electrical connections in subsequent steps.
  • the preparation method of the anti-reflection layer 113 may also be to form the anti-reflection layer 113 while forming the cut-off ring 112 .
  • the anti-reflection layer 113 is made of silicon nitride. .
  • the preparation method of the antireflection layer 113 may further include the following steps:
  • the cut-off ring material layer is thinned to form the antireflection layer 113.
  • the cut-off ring material layer can be thinned differently. The thickness reserved in other areas is thinner;
  • the anti-reflection layer 113 is patterned to form a first opening and expose the first electrode 106 and the second doped layer 108, as shown in FIG. 1I.
  • the preparation method also includes:
  • a first electrode contact layer 115 is formed on the exposed first electrode 106 to form an electrical connection with the first electrode 106
  • a second electrode contact layer 114 is formed on the second doped layer 108 to form an electrical connection with the first electrode 106 .
  • An electrical connection is formed on the second doped layer 108 . As shown in Figure 1J.
  • the first electrode contact layer 115 and the second electrode contact layer 114 are conductive metals to form electrical connections, wherein the conductive metals may be aluminum or copper, but are not limited to this example.
  • the method further includes:
  • the passivation layer 116 is patterned to form a second opening and expose the first electrode contact layer 115 , the second electrode contact layer 114 and the antireflection layer 113 , as shown in FIG. 1L .
  • the depth of the peak concentration of the first ion implantation of the first doped layer is greater than or equal to 2 ⁇ m, and the first ion implantation The dose is 1 ⁇ 10 12 cm -3 to 3 ⁇ 10 12 cm -3 .
  • the first ions increase slowly between the surface of the epitaxial layer and the peak concentration.
  • the avalanche region will be expanded accordingly, so that in the same Under the condition of breakdown voltage, the electric field strength of the avalanche region is reduced, thereby reducing the gain and noise factor of the avalanche region.
  • the present application provides an avalanche photodiode, as shown in FIG. 1L, the avalanche photodiode includes:
  • the avalanche region located in the epitaxial layer, includes the first doping layer 109 and the second doping layer 108 and the region between the first doping layer 109 and the second doping layer 108 ,in:
  • the first doping layer 109 has a first doping type, the depth of the peak concentration of the first doping layer 109 is greater than or equal to 2 ⁇ m, and the doping dose of the first doping layer 109 is 1 ⁇ 10 12 cm -3 ⁇ 3 ⁇ 10 12 cm -3 ;
  • the second doping layer 108 located above the first doping layer 109, has a second doping type, and the first doping type is different from the second doping type.
  • the avalanche photodiode further includes a substrate 101, wherein the substrate 101 may be at least one of the following materials: silicon, silicon-on-insulator (SOI), Silicon on insulator (SSOI), silicon germanium on insulator (S-SiGeOI), silicon germanium on insulator (SiGeOI), germanium on insulator (GeOI), etc.
  • SOI silicon-on-insulator
  • SSOI Silicon on insulator
  • SiGeOI silicon germanium on insulator
  • SiGeOI silicon germanium on insulator
  • GeOI germanium on insulator
  • the substrate 101 is made of silicon.
  • the substrate 101 is a heavily doped substrate, and the heavily doped substrate can be used as an electrode in the subsequent steps, thereby leading out the signal of the avalanche photodiode.
  • the doping concentration of the substrate is 5 ⁇ 10 18 /cm 3 to 5 ⁇ 10 20 /cm 3 .
  • the epitaxial layer 102 can be made of semiconductor material, and in an embodiment of the present application, an epitaxial silicon wafer is selected.
  • the thickness of the epitaxial layer 102 is approximately 60 ⁇ m, and the thickness of the epitaxial layer 102 is not limited to a certain value range.
  • the epitaxial layer 102 is a silicon layer with an incident wavelength of 850 nm to 940 nm.
  • the incident wavelength of the epitaxial layer 102 is 905 nm.
  • the epitaxial layer 102 includes a first surface and a second surface disposed opposite to each other, the second surface of the epitaxial layer 102 is disposed on the substrate 101, and the first surface of the epitaxial layer 102 is far away from the substrate Bottom 101.
  • the first surface is a front surface
  • the second surface is a back surface.
  • the avalanche photodiode may be a back-illuminated device or a front-illuminated device, and is not limited to any one.
  • the avalanche photodiode can be a back-illuminated device, that is, in the back-illuminated device where the photosensitive device APD is located in front of the circuit transistor, light first enters the photosensitive device APD, thereby increasing the photosensitive amount.
  • the APD is formed on the first surface of the epitaxial layer 102 , that is, the front surface of the epitaxial layer 102 , and the light is taken in from the back surface of the epitaxial layer 102 , that is, the light enters from the second surface of the epitaxial layer 102 .
  • the epitaxial layer 102 has a low doping type, and the doping type may be N-type or P-type. Generally, the epitaxial layer 102 is P-type doped.
  • setting the epitaxial layer 102 to a low-doped type can reduce the consumption of photogenerated carriers in the APD, thereby quickly reaching the avalanche collection area of the APD, and improving the corresponding speed of the APD, Avoid the tailing problem of APD and avoid the delay of the device.
  • the electric field strength of the avalanche region is adjusted by adjusting the implantation depth and dose of the first doped layer 109, so as to realize the optimization of the device gain and noise factor.
  • the depth of the peak concentration of the first doped layer 109 is greater than or equal to 2 ⁇ m
  • the dose of ion implantation of the first doped layer 109 is 1 ⁇ 10 12 cm ⁇ 3 to 3 ⁇ 10 12 cm ⁇ 3.
  • the first ion implantation is P-type ion implantation.
  • the P-type ions are B ions.
  • the concentration of the first ions increases slowly between the surface of the epitaxial layer 102 and the peak concentration, that is, the epitaxial layer can be realized by one ion implantation.
  • Layer 102 implements the P++/P--/P++ structure.
  • the energy injected into the first doped layer 109 is 1200keV ⁇ 1600keV.
  • the first doped layer 109 is formed by first ion implantation, and the included angle between the direction of the first ion implantation and a plane perpendicular to the surface of the epitaxial layer 102 is 0°-10°.
  • the distribution of doping impurities after the ion implantation is controlled by controlling the direction of the first ion implantation, for example, the angle between the direction of the first ion implantation and the plane perpendicular to the surface of the epitaxial layer 102
  • the concentration of doping impurities will gradually increase after the first ion implantation, and will reach a peak value, so that the electric field distribution of the prepared avalanche photodiode is more uniform, and the absorption rate of the avalanche region is improved. higher.
  • the angle between the direction of the first ion implantation and a plane perpendicular to the surface of the epitaxial layer 102 is 0 degrees.
  • the angle between the direction of the first ion implantation and a plane perpendicular to the surface of the epitaxial layer is 7 degrees.
  • the second doped layer 108 is located above the first doped layer 109 .
  • the first doped layer 109 and the second doped layer 108 and the region between the first doped layer 109 and the second doped layer 108 constitute the avalanche region of the avalanche photodiode.
  • the first doping type is different from the second doping type, wherein the first ion implantation is P-type, and the second ion implantation is N-type, in an embodiment of the present application , the second ion implantation is P (phosphorus) ion or As ion.
  • the top of the epitaxial layer 102 is the second doped layer 108
  • the lower part is the first doped layer 109
  • a transition region between the two such as the first doped layer 109 .
  • the P- under the second doping layer 108, the P+ layer with increasing concentration, and the epitaxial layer further form the N++/P-/P+/P--/P++ structure of the avalanche photodiode.
  • an absorbing layer and the like may be further included below the avalanche region, which will not be repeated here.
  • the depth of the peak concentration of the second doping layer 108 is less than or equal to 200 nm, and in one embodiment of the present application, the depth of the peak concentration of the second doping layer 108 is 100 nm.
  • the implantation dose of the second doped layer 108 is 1 ⁇ 10 14 cm ⁇ 3 ⁇ 1 ⁇ 10 15 cm ⁇ 3 ; the implantation energy of the second doped layer 108 is 20 keV ⁇ 100 keV.
  • a rapid annealing step may be performed.
  • the temperature of the rapid annealing is 900 degrees Celsius to 1150 degrees Celsius and the time is 10s to 60s to activate the implanted ions and eliminate the Ion implantation defects.
  • the avalanche photodiode includes: the guard ring 105 located in the epitaxial layer 102 , and the guard ring 105 surrounds the second doped layer 108 .
  • a guard ring 105 is first formed in the epitaxial layer 102 , and in the subsequent second ion implantation step, the second ion implantation is performed in the guard ring 105 to form the guard ring 105 .
  • the second doped layer 108 surrounded by the guard ring 105 is formed by forming the guard ring 105 to prevent edge breakdown, thereby further improving the yield and performance of the device.
  • the step of forming the guard ring 105 may be before the first ion implantation of the first doping type, or after the first ion implantation of the first doping type and after the second doping type
  • the type of second ion implantation can be selected according to actual needs.
  • the guard ring 105 is formed before the first ion implantation of the first doping type.
  • the guard ring 105 is formed by ion implantation; or the guard ring 105 includes a groove and a filling material in the groove.
  • the method for forming the guard ring 105 includes: forming a patterned mask layer on the epitaxial layer 102 to expose the area where the guard ring 105 is to be formed; A third ion implantation of the second doping type forms the guard ring 105 in the exposed area.
  • the second doping type is N-type
  • the third ion implantation is P (phosphorus) ion or As ion.
  • the third ion implantation is P (phosphorus) ions. Compared with As ions, P (phosphorus) ions have smaller ions and deeper implantation depths, and have better protection effects.
  • the third ion implantation is implemented by means of multiple ion implantation, and the multiple ion implantation can make the distribution of ions after implantation more uniform and have better protection effect.
  • the energy of the third ion implantation is 20keV ⁇ 800keV
  • the dose of the third ion implantation is 1 ⁇ 10 12 cm ⁇ 3 to 4 ⁇ 10 12 cm ⁇ 3 .
  • the depth of the guard ring 105 is greater than or equal to 2 ⁇ m.
  • the depth of the guard ring 105 is greater than or equal to 2 ⁇ m.
  • the method for forming the guard ring 105 may further include the following steps:
  • the epitaxial layer 102 is etched to form a trench; wherein the depth of the trench is greater than or equal to 2 ⁇ m.
  • the trench is then filled to form the guard ring 105 to perform the second ion implantation within the guard ring 105 and to form the second doped layer surrounded by the guard ring.
  • the avalanche layer of the avalanche photodiode described in the present application can be formed through the above steps, and the electric field strength of the avalanche region can be effectively adjusted by adjusting the implantation depth and dose of the first doped layer, so as to realize the optimization of the device gain and noise factor.
  • the avalanche photodiode further includes a first electrode, and the first electrode 106 is located in the region of the edge of the epitaxial layer.
  • the first electrode 106 is formed by B ion implantation for electrical connection and isolation between pixels.
  • the avalanche photodiode further includes a cut-off ring 112 formed on the surface of the epitaxial layer 102 between the guard ring 105 and the first electrode 106 .
  • the thickness of the cut-off ring 112 is generally more than 500 nm. By setting the cut-off ring 112 with this thickness, the second doping layer 108 can be prevented from being pressurized below the cut-off ring 112 corresponding to the voltage region to form an inversion layer, resulting in the second doping
  • the layer 108 and the first electrode 106 are conductive.
  • cut-off ring 112 can also be used to neutralize the surface state of the epitaxial layer 102 to further prevent the conduction between the second doped layer 108 and the first electrode 106 .
  • the avalanche photodiode further includes an anti-reflection layer 113, the anti-reflection layer 113 is located on the epitaxial layer 102 and covers the surface of the epitaxial layer 102 and the cut-off ring 112, wherein the anti-reflection layer 113 There is a first opening located above the first electrode 106 and the second doped layer 108 .
  • the anti-reflection layer 113 can be selected from silicon nitride or silicon oxide.
  • the avalanche photodiode further includes a first electrode contact layer 115 and a second electrode contact layer 114 , wherein a first electrode contact layer 115 is formed on the exposed first electrode 106 to communicate with the first electrode 106 An electrical connection is formed while a second electrode contact layer 114 is formed on the second doped layer 108 to form an electrical connection with the second doped layer 108 .
  • the first electrode contact layer 115 and the second electrode contact layer 114 are conductive metals to form electrical connections, wherein the conductive metals may be aluminum or copper, but are not limited to this example.
  • the avalanche photodiode further includes 116 formed on the epitaxial layer 102;
  • the passivation layer 116 has a second opening and exposes the first electrode contact layer 115 , the second electrode contact layer 114 and the antireflection layer 113 .
  • the depth of the peak concentration of the first ion implantation of the first doped layer is greater than or equal to 2 ⁇ m, and the first ion implantation
  • the dose is 1 ⁇ 10 12 cm -3 to 3 ⁇ 10 12 cm -3 .
  • the avalanche region When the first doped layer is implanted to a depth of more than 2um, the avalanche region will be expanded accordingly, thereby reducing the electric field strength of the avalanche region under the same breakdown voltage, thereby reducing the gain and noise factor of the avalanche region.
  • the present application also provides a receiving chip, wherein the receiving chip includes:
  • the aforementioned avalanche photodiode is used to receive the optical pulse sequence reflected by the detected object, and convert the received optical pulse sequence into a current signal;
  • the signal processing unit is used for receiving and processing the current signal of the avalanche photodiode to output a time signal.
  • the avalanche photodiode may be included on an avalanche photodiode chip
  • the signal processing unit may be included on a signal processing unit chip
  • the avalanche photodiode and the processing unit may be electrically connected to transmit the current signal. to the signal processing unit for processing.
  • the avalanche photodiode chip and the signal processing chip are electrically connected, the avalanche photodiode chip and the signal processing chip are stacked up and down, and connected in the form of vertical interconnection, such as connecting bumps (copper pillars) to connecting bumps (copper pillars), Connecting bumps (copper pillars) to an interposer (including a through-silicon via interconnect structure penetrating the upper and lower surfaces of the interposer and a conductive layer on the upper and lower surfaces of the interposer and electrically connected to the through-silicon via interconnect structure) , to avoid the problem of light blocking or mutual interference caused by the way of line connection.
  • interposer including a through-silicon via interconnect structure penetrating the upper and lower surfaces of the interposer and a conductive layer on the upper and lower surfaces of the interposer and electrically connected to the through-silicon via interconnect structure
  • connection bump can be 50 ⁇ m in diameter and 100 ⁇ m in pitch, which can avoid the current solder balls and connection pads. It is difficult to make it small (minimum 200 ⁇ m) and it is easy to break the circuit, and the height of the connection bump can be more than 100 ⁇ m, the tensile strength is increased, and the reliability can be effectively improved.
  • the signal processing unit integrates a plurality of circuits.
  • the signal processing unit integrates a transimpedance amplifier circuit (TIA circuit), a multi-stage operational amplifier OPA, a comparator, and a time-to-digital converter (time-to-digital converter).
  • TIA circuit transimpedance amplifier circuit
  • OPA operational amplifier
  • comparator comparator
  • time-to-digital converter time-to-digital converter
  • a circuit converted into a digital signal or an analog-to-digital conversion circuit (ADC circuit), and a subsequent data processing circuit (DSP circuit).
  • DSP circuit data processing circuit
  • the TIA circuit is an analog front-end circuit that converts the APD photocurrent into a voltage.
  • the avalanche photodiode needs an external high-voltage power supply when converting an optical signal into a current signal, and the APD can provide a stable internal gain and improve the signal-to-noise ratio to output a current signal.
  • the TIA circuit is electrically connected to the avalanche photodiode, the TIA circuit converts the current signal of the APD into a voltage signal, and provides a conversion gain at the same time; a multi-stage operational amplifier OPA and the TIA circuit The electrical connection is used to amplify the signal output by the TIA circuit to meet the comparison amplitude requirement of the comparator.
  • the comparator is electrically connected to the multi-stage operational amplifier OPA, wherein a comparison threshold is set in the comparator to trigger the analog signal, convert the analog signal into a digital signal, and transmit the signal to the TDC circuit, and the TDC circuit is used to convert the analog signal into a digital signal.
  • the digital signal is converted to a time signal for distance calculation.
  • one TDC circuit may be shared, that is, the number of signal processing units may not correspond to the number of TDC circuits.
  • a storage system may be further provided in the signal processing unit to cache data, provide input and output buffer space for the interface, and provide space for internal calculation.
  • An interface can be further set in the signal processing unit to serve as a data input and output channel to output the measurement data.
  • the first input terminal of the comparator is used to receive the electrical signal input from the amplifiers across the group, that is, the electrical signal after the amplification operation
  • the second input terminal of the comparator is used to receive the preset Threshold
  • the output end of the comparator is used to output the result of the comparison operation, wherein the result of the comparison operation includes time information corresponding to the electrical signal.
  • the preset threshold value received by the second input end of the comparator may be an electrical signal whose intensity is the preset threshold value.
  • the result of the comparison operation may be a digital signal corresponding to the electric signal after the amplification operation.
  • the time-to-digital converter (Time-to-Digital Converter, TDC) is electrically connected to the output end of the comparator, and is used for extracting time information corresponding to the electrical signal according to the result of the comparison operation output by the comparator.
  • TDC Time-to-Digital Converter
  • the receiving chip adopts the avalanche photodiode provided in this application.
  • the avalanche photodiode is a second doped layer-first doped layer structure
  • the depth of the peak concentration of the first ion implantation of the first doped layer is greater than or equal to 2 ⁇ m
  • the first ion implantation The dose is 1 ⁇ 10 12 cm -3 to 3 ⁇ 10 12 cm -3 .
  • the present application also provides a ranging device.
  • the avalanche photodiodes or receiving chips provided in the various embodiments of the present application can be applied to the ranging device, and the ranging device can be an electronic device such as a laser radar or a laser ranging device.
  • the ranging device is used to sense external environmental information, for example, distance information, orientation information, reflection intensity information, speed information and the like of environmental objects.
  • the ranging device can detect the distance from the detected object to the ranging device by measuring the time of light propagation between the ranging device and the detected object, that is, Time-of-Flight (TOF).
  • TOF Time-of-Flight
  • the ranging device can also detect the distance from the detected object to the ranging device through other technologies, such as a ranging method based on phase shift measurement, or a ranging method based on frequency shift measurement. This does not limit.
  • the distance measuring device of the present application includes the avalanche photodiode provided in the foregoing embodiments, where the avalanche photodiode is a second doped layer-first doped layer structure, and the first doped layer
  • the depth of the peak concentration of ion implantation is greater than or equal to 2 ⁇ m, and the dose of the first ion implantation is 1 ⁇ 10 12 cm ⁇ 3 to 3 ⁇ 10 12 cm ⁇ 3 .
  • the ranging device may be a mechanical rotating laser radar or a solid-state laser radar: in the mechanical rotating laser radar, mechanical rotation is used to change the optical path to scan; the solid-state laser radar can be directly transmitted in a short time A pulsed laser that can cover the detection area is generated, and then a highly sensitive area array receiving chip is used to receive the echo signal, and the detection and perception of the distance information of the surrounding environment are completed by a mode similar to the camera taking pictures.
  • the ranging device is a mechanical rotating laser radar.
  • the working process of ranging by the ranging device is described as an example below.
  • the ranging device may include a transmitting circuit, a receiving chip and an arithmetic circuit.
  • the receiving chip includes the aforementioned avalanche photodiode and a signal processing unit.
  • each signal processing unit may be provided with a transimpedance amplifier circuit (TIA circuit) independently, wherein the time-to-digital converter (TDC) may be provided independently, and a plurality of transimpedance amplifier circuits ( TIA circuits) share one of the time-to-digital converters (TDCs), and the time-to-digital converters (TDCs) can switch to different channels to receive and process signals from the transimpedance amplifier circuits (TIA circuits).
  • TDC time-to-digital converter
  • TDCs time-to-digital converters
  • the operation circuit may also be set independently or a plurality of the signal processing units may share one of the operation circuit.
  • the transmit circuit may transmit a sequence of optical pulses (eg, a sequence of laser pulses).
  • the receiving chip can receive the optical pulse sequence reflected by the detected object, and output a time signal based on the received optical pulse sequence.
  • the arithmetic circuit may determine the distance between the distance measuring device and the detected object based on the time signal.
  • the distance measuring device may further include a control circuit, which can control other circuits, for example, can control the working time of each circuit and/or set parameters for each circuit.
  • a control circuit which can control other circuits, for example, can control the working time of each circuit and/or set parameters for each circuit.
  • the ranging device may further include a scanning module, configured to change the propagation direction of at least one laser pulse sequence emitted from the transmitting circuit to emit.
  • a module including a transmitting circuit, a receiving chip, and an arithmetic circuit or a module including a transmitting circuit, a receiving chip, an arithmetic circuit, and a control circuit may be called a ranging module, and the ranging module may be independent of other modules, for example, Scan module.
  • a coaxial optical path may be used in the ranging device, that is, the light beam emitted by the ranging device and the reflected light beam share at least part of the optical path in the ranging device.
  • the laser pulse sequence reflected by the detection object passes through the scanning module and then enters the receiver.
  • the distance-measuring device may also adopt an off-axis optical path, that is, the light beam emitted by the distance-measuring device and the reflected light beam are respectively transmitted along different optical paths in the distance-measuring device.
  • FIG. 3 shows a schematic diagram of an embodiment in which the distance measuring device of the present application adopts a coaxial optical path.
  • the ranging device 200 includes a ranging module 210, and the ranging module 210 includes a transmitter 203 (which may include the above-mentioned transmitting circuit), a collimating element 204, and a detector 205 (the receiving chip may include the detector 205, and the detector includes the above-described avalanche photodiode) and optical path changing element 206.
  • the ranging module 210 is used for emitting a light beam, receiving the returning light, and converting the returning light into an electrical signal.
  • the transmitter 203 can be used to transmit a sequence of optical pulses. In one embodiment, the transmitter 203 may emit a sequence of laser pulses.
  • the laser beam emitted by the transmitter 203 is a narrow bandwidth beam with a wavelength outside the visible light range.
  • the collimating element 204 is disposed on the outgoing light path of the transmitter, and is used for collimating the light beam emitted from the transmitter 203, and collimating the light beam emitted by the transmitter 203 into parallel light and outputting to the scanning module.
  • the collimating element also serves to converge at least a portion of the return light reflected by the probe.
  • the collimating element 204 may be a collimating lens or other elements capable of collimating light beams.
  • the transmitting optical path and the receiving optical path in the ranging device are combined by the optical path changing element 206 before the collimating element 204, so that the transmitting optical path and the receiving optical path can share the same collimating element, so that the optical path more compact.
  • the emitter 203 and the detector 205 may use respective collimating elements, and the optical path changing element 206 may be arranged on the optical path behind the collimating element.
  • the optical path changing element can use a small-area reflective mirror to The transmit light path and the receive light path are combined.
  • the optical path changing element may also use a reflector with a through hole, wherein the through hole is used to transmit the outgoing light of the emitter 203 , and the reflector is used to reflect the return light to the detector 205 . In this way, in the case of using a small reflector, the occlusion of the return light by the support of the small reflector can be reduced.
  • the optical path changing element is offset from the optical axis of the collimating element 204 .
  • the optical path altering element may also be located on the optical axis of the collimating element 204 .
  • the ranging device 200 further includes a scanning module 202 .
  • the scanning module 202 is placed on the outgoing optical path of the ranging module 210 .
  • the scanning module 202 is used to change the transmission direction of the collimated beam 219 emitted by the collimating element 204 and project it to the external environment, and project the return light to the collimating element 204 .
  • the returned light is focused on the detector 205 through the collimating element 204 .
  • the scanning module 202 can include at least one optical element for changing the propagation path of the light beam, wherein the optical element can change the propagation path of the light beam by reflecting, refracting, diffracting the light beam, or the like.
  • the scanning module 202 includes lenses, mirrors, prisms, gratings, liquid crystals, optical phased arrays (Optical Phased Array) or any combination of the above optical elements.
  • at least part of the optical elements are moving, for example, the at least part of the optical elements are driven to move by a driving module, and the moving optical elements can reflect, refract or diffract the light beam to different directions at different times.
  • the multiple optical elements of the scanning module 202 may be rotated or oscillated about a common axis 209, each rotating or oscillating optical element being used to continuously change the propagation direction of the incident beam.
  • the plurality of optical elements of the scanning module 202 may rotate at different rotational speeds, or vibrate at different speeds.
  • at least some of the optical elements of scan module 202 may rotate at substantially the same rotational speed.
  • the plurality of optical elements of the scanning module may also be rotated about different axes.
  • the plurality of optical elements of the scanning module may also rotate in the same direction, or rotate in different directions; or vibrate in the same direction, or vibrate in different directions, which are not limited herein.
  • the scanning module 202 includes a first optical element 214 and a driver 216 connected to the first optical element 214, and the driver 216 is used to drive the first optical element 214 to rotate around the rotation axis 209, so that the first optical element 214 changes The direction of the collimated beam 219.
  • the first optical element 214 projects the collimated beam 219 in different directions.
  • the angle between the direction of the collimated light beam 219 changed by the first optical element and the rotation axis 209 changes as the first optical element 214 rotates.
  • the first optical element 214 includes a pair of opposing non-parallel surfaces through which the collimated beam 219 passes.
  • the first optical element 214 includes a prism whose thickness varies along at least one radial direction.
  • the first optical element 214 includes a wedge prism that refracts the collimated light beam 219 .
  • the scanning module 202 further includes a second optical element 215 , the second optical element 215 rotates around the rotation axis 209 , and the rotation speed of the second optical element 215 is different from the rotation speed of the first optical element 214 .
  • the second optical element 215 is used to change the direction of the light beam projected by the first optical element 214 .
  • the second optical element 215 is connected to another driver 217, and the driver 217 drives the second optical element 215 to rotate.
  • the first optical element 214 and the second optical element 215 can be driven by the same or different drivers, so that the rotational speed and/or steering of the first optical element 214 and the second optical element 215 are different, thereby projecting the collimated beam 219 into the external space Different directions can scan a larger spatial range.
  • the controller 218 controls the drivers 216 and 217 to drive the first optical element 214 and the second optical element 215, respectively.
  • the rotational speeds of the first optical element 214 and the second optical element 215 may be determined according to the area and pattern expected to be scanned in practical applications.
  • Drives 216 and 217 may include motors or other drives.
  • the second optical element 215 includes a pair of opposing non-parallel surfaces through which the light beam passes.
  • the second optical element 215 comprises a prism whose thickness varies along at least one radial direction.
  • the second optical element 215 comprises a wedge prism.
  • the scanning module 202 further includes a third optical element (not shown) and a driver for driving the movement of the third optical element.
  • the third optical element includes a pair of opposing non-parallel surfaces through which the light beam passes.
  • the third optical element comprises a prism of varying thickness along at least one radial direction.
  • the third optical element comprises a wedge prism. At least two of the first, second and third optical elements rotate at different rotational speeds and/or rotations.
  • FIG. 4 is a schematic diagram of a scanning pattern of the distance measuring device 200 . It can be understood that when the speed of the optical element in the scanning module changes, the scanning pattern also changes accordingly.
  • the scanning module 202 When the light 211 projected by the scanning module 202 hits the detected object 201 , a part of the light is reflected by the detected object 201 to the distance measuring device 200 in a direction opposite to the projected light 211 .
  • the returning light 212 reflected by the probe 201 passes through the scanning module 202 and then enters the collimating element 204 .
  • a detector 205 is placed on the same side of the collimating element 204 as the emitter 203, and the detector 205 is used to convert at least part of the return light passing through the collimating element 204 into an electrical signal.
  • each optical element is coated with an anti-reflection coating.
  • the thickness of the anti-reflection film is equal to or close to the wavelength of the light beam emitted by the emitter 203, which can increase the intensity of the transmitted light beam.
  • a filter layer is coated on the surface of an element located on the beam propagation path in the distance measuring device, or a filter is provided on the beam propagation path for transmitting at least the wavelength band of the light beam emitted by the transmitter, Reflect other bands to reduce noise from ambient light to the receiver chip.
  • the transmitter 203 may comprise a laser diode through which laser pulses are emitted on the nanosecond scale.
  • the laser pulse receiving time can be determined, for example, by detecting the rising edge time and/or the falling edge time of the electrical signal pulse to determine the laser pulse receiving time.
  • the ranging apparatus 200 can calculate the TOF by using the pulse receiving time information and the pulse sending time information, so as to determine the distance from the probe 201 to the ranging apparatus 200 .
  • the distance and orientation detected by the ranging device can be used for remote sensing, obstacle avoidance, mapping, modeling, navigation, etc., such as realizing the perception of the surrounding environment, and performing two-dimensional or three-dimensional mapping of the external environment.
  • the distance measuring device of the embodiment of the present application can be applied to the movable platform.
  • the present application also provides a movable platform, wherein the distance measuring device described above can be applied to the movable platform, and the distance measuring device can be installed on the movable platform body of the movable platform.
  • the movable platform includes at least one of an unmanned aerial vehicle, a car, a remote control car, a robot, and a camera.
  • the ranging device is applied to the unmanned aerial vehicle
  • the movable platform body is the fuselage of the unmanned aerial vehicle.
  • the movable platform body is the body of the automobile.
  • the vehicle may be an autonomous driving vehicle or a semi-autonomous driving vehicle, which is not limited herein.
  • the movable platform body is the body of the remote control car.
  • the movable platform body is the body of the robot.
  • the movable platform body is the body of the robot.
  • the ranging device is applied to the camera
  • the movable platform body is the body of the camera.
  • the movable platform may further include a power system for driving the movable platform body to move.
  • the power system may be an engine inside the vehicle, which will not be listed here.
  • the disclosed apparatus and method may be implemented in other manners.
  • the device embodiments described above are only illustrative.
  • the division of the units is only a logical function division. In actual implementation, there may be other division methods.
  • multiple units or components may be combined or May be integrated into another device, or some features may be omitted, or not implemented.
  • Various component embodiments of the present application may be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof.
  • a microprocessor or a digital signal processor (DSP) may be used in practice to implement some or all functions of some modules according to the embodiments of the present application.
  • DSP digital signal processor
  • the present application can also be implemented as a program of apparatus (eg, computer programs and computer program products) for performing part or all of the methods described herein.
  • Such a program implementing the present application may be stored on a computer-readable medium, or may be in the form of one or more signals. Such signals may be downloaded from Internet sites, or provided on carrier signals, or in any other form.

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Abstract

La présente invention concerne une photodiode à avalanche et son procédé de fabrication, une puce de réception, un dispositif de mesure de distance et une plateforme mobile. Le procédé de fabrication consiste à : fournir un substrat sur lequel une couche épitaxiale est formée ; réaliser une première implantation d'ions d'un premier type de dopage sur la couche épitaxiale pour former une première couche dopée, la profondeur de la concentration de pic de la première implantation d'ions étant supérieure ou égale à 2 µm, et la dose de la première implantation d'ions étant est de 1×1012cm-3-3×1012cm-3 ; et réaliser une seconde implantation d'ions d'un second type de dopage sur la couche épitaxiale pour former une seconde couche dopée, la seconde couche dopée étant située au-dessus de la première couche dopée, le premier type de dopage étant différent du second type de dopage, et la première couche dopée, la seconde couche dopée et une région entre la première couche dopée et la seconde couche dopée constituant une région d'avalanche de la photodiode à avalanche.
PCT/CN2020/118170 2020-09-27 2020-09-27 Diode et son procédé de fabrication, puce de réception, dispositif de mesure de distance et plateforme mobile WO2022061831A1 (fr)

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PCT/CN2020/118170 WO2022061831A1 (fr) 2020-09-27 2020-09-27 Diode et son procédé de fabrication, puce de réception, dispositif de mesure de distance et plateforme mobile
CN202080014793.6A CN114556533A (zh) 2020-09-27 2020-09-27 二极管及其制备方法、接收芯片、测距装置、可移动平台

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