# US 10,312,391 B2 · Apparatus and method for single-photon avalanche-photodiode detectors with reduced dark count rate > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,312,391 B2 - Document ID: US10312391B2 - Status: Granted - Kind: B2 - Application number: 15/285,201 - Filed: 2016-10-04 - Published: 2018-04-05 - Granted: 2019-06-04 - Earliest claimed: 2016-10-04 - Assignees: OmniVision Technologies, Inc. - Applicants: OmniVision Technologies, Inc. - Inventors: Gang Chen; Duli Mao; Vincent Venezia; Dyson H. Tai; Bowei Zhang - Web page: https://patentgrep.com/patent/US10312391B2 ## CPC - H10F 77/14: Shape of semiconductor bodies; Shapes, relative sizes or dispositions of semiconductor regions within semiconductor bodies - H10F 30/225: the potential barrier working in avalanche mode, e.g. avalanche photodiodes - H10F 39/103: {the at least one element covered by H10F30/00 having potential barriers, e.g. integrated devices comprising photodiodes or phototransistors} - H10F 77/206: {for devices having potential barriers} - H10F 77/959: {for devices working in avalanche mode} - H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION ## Abstract An avalanche photodiode has a first diffused region of a first diffusion type overlying at least in part a second diffused region of a second diffusion type; and a first minority carrier sink region disposed within the first diffused region, the first minority carrier sink region of the second diffusion type and electrically connected to the first diffused region. In particular embodiments, the first diffusion type is N-type and the second diffusion type is P-type, and the device is biased so that a depletion zone having avalanche multiplication exists between the first and second diffused regions. ## Claims ### Claim 1 An avalanche photodiode comprising: a first diffused region of a first diffusion type; the first diffused region overlying at least in part a second diffused region of a second diffusion type; a first minority carrier sink region disposed within the first diffused region, the first minority carrier sink region being of the second diffusion type; and a second minority carrier sink region, disposed within the second diffused region, the second minority carrier sink region being of the first diffusion type; wherein the first and second diffused regions are configured such that a depletion zone having avalanche multiplication characteristics forms between the first diffused region and the second diffused region when under bias. ### Claim 2 (depends on 1) The avalanche photodiode of claim 1 wherein the first minority carrier sink region is electrically connected to the first diffused region. ### Claim 3 (depends on 1) The avalanche photodiode of claim 1 wherein the first minority carrier sink region is formed as an inversion region by applying a bias to an electrode overlying the first diffused region. ### Claim 4 An avalanche photodiode comprising: a first diffused region of a first diffusion type; the first diffused region overlying at least in part a second diffused region of a second diffusion type; and a first minority carrier sink region disposed within the first diffused region, the first minority carrier sink region being of the second diffusion type; further comprising a second minority carrier sink region, disposed within the second diffused region, the second minority carrier sink region being of the first diffusion type, and electrically connected to the second diffused region; wherein the first and second diffused regions are configured such that a depletion zone having avalanche multiplication characteristics forms between the first diffused region and the second diffused region when under bias; wherein the first minority carrier sink region is electrically connected to the first diffused region. ### Claim 5 (depends on 4) The avalanche photodiode of claim 4, the first diffusion type being N type and the second diffusion type being P type. ### Claim 6 (depends on 5) The avalanche photodiode of claim 5, a shape of the first minority carrier sink region being a grid. ### Claim 7 (depends on 6) The avalanche photodiode of claim 6, a shape of the second minority carrier sink region being a grid. ### Claim 8 (depends on 5) An avalanche photodetector comprising the avalanche photodiode claim 5, further comprising voltage bias circuitry adapted to apply a voltage bias to the first diffused region relative to the second diffused region sufficient that the depletion zone having avalanche multiplication characteristics forms between the first and second diffused regions. ### Claim 9 (depends on 8) The avalanche photodetector of claim 8, the voltage bias being configured to operate the avalanche photodetector in a single-photon counting mode. ### Claim 10 A method of detecting photons comprising: providing a reverse bias to an avalanche photodiode having an N region and a P region, and thereby forming a depletion zone between the N region and P region; attracting minority carriers to a P-type first minority carrier sink from portions of the N region opposite the depletion zone and attracting minority carriers to an N-type second minority carrier sink from the P region opposite the depletion zone; receiving photons and forming carrier pairs; amplifying the carrier pairs in the depletion zone to produce a detectable current-flow; quenching current flow; and re-biasing the N and P regions. ### Claim 11 (depends on 10) The method of claim 10, wherein the first minority carrier sink is a shallow P type region embedded in the N region of the photodiode. ### Claim 12 (depends on 11) The method of claim 11, wherein the first minority carrier sink is electrically connected to the N region of the photodiode. ### Claim 13 (depends on 12) The method of claim 12, wherein the first minority carrier sink is embedded in a portion of the N region of the photodiode opposite from the depletion zone. ### Claim 14 A method of detecting photons comprising: providing a reverse bias to an avalanche photodiode having an N region and a P region, and thereby forming a depletion zone between the N region and P region; attracting minority carriers to minority carrier sinks from portions of the N region and the P region opposite the depletion zone; receiving photons and forming carrier pairs; amplifying the carrier pairs in the depletion zone to produce a detectable current-flow; quenching current flow; and re-biasing the N and P regions; wherein a first minority carrier sink is a shallow P type region embedded in the N region of the photodiode, the first minority carrier sink is electrically connected to the N region of the photodiode and embedded in a portion of the N region of the photodiode opposite from the depletion zone; and wherein a second minority carrier sink is an N-type region embedded in the P region of the photodiode. ### Claim 15 (depends on 14) The method of claim 14, wherein the second minority carrier sink is electrically connected to the P region of the photodiode. ### Claim 16 (depends on 15) The method of claim 15, wherein the first minority carrier sink is embedded in a portion of the P region of the photodiode opposite from the depletion zone.