Research On Infrared Enhanced Silicon-based Single Photon Avalanche Diode

With the rapid development of technologies such as lidar and quantum communication,high-ly integrated,low-cost extremely weak infrared light detection technology is facing greater challenges.Single-photon avalanche diodes are the core components of weak light detec-tion systems.At present,silicon-based single-photon avalanche diodes are the core devices of extremely weak light detection systems.Due to their low noise,mature technology,low manufacturing cost,and high integration with CMOS circuits,they have widely used in the field of extremely weak light detections.However,the low infrared detection efficiency se-riously restricts the application range of silicon-based single-photon avalanche diodes.How to improve the photon detection efficiency of the infrared sensitive detection of silicon-based single-photon avalanche diodes and move its detection range to the long wave has become a hot topic in international research.This paper focuses on the research and design of infrared enhanced silicon-based single-photon avalanche diodes.First,based on the mechanism research of traditional silicon-based single-photon avalanche diodes,a new structure of silicon-based single-photon avalanche diodes with high detection efficiency in the near-infrared band is designed,that is,a double-buried layer structure.At the same time,using Silvaco TCAD software to carry out physical simulation modeling of infrared enhanced silicon-based single photon avalanche diodes,ex-tracting key parameters such as I-V characteristics,electric field distribution,and avalanche probability.On this basis,numerical models of the main performance parameters such as photon detection efficiency and dark count rate based on the dead zone effect and quantum efficiency are established.The simulation results show that under the condition of 870 n-m wavelength,the photon detection efficiency of the double-buried single structure photon avalanche diode can reach 11.9%,and its detection efficiency in the near infrared band is improved compared with the traditional silicon-based single photon avalanche diode.In order to improve the near-infrared detection efficiency of the single-photon avalanche diode with double-buried layer structure,based on the analysis results of the simulation model and the numerical model,the near-infrared detection efficiency of the structure was optimized.The optimal structural parameters are the thickness of the depletion region T_d=5?m,the diameter of the P-type buried layer R_pb=14?m and the doping concentration of the P-type buried layer N_pb=1.9×10¹⁷/cm³.The optimization results show that the detection efficiency of single-photon avalanche diode with double buried layer structure reaches 18.6%under the condition of 870 nm wavelength.Compared with the reference single-photon avalanche diode,its detection efficiency in the near infrared band has been greatly improved.In order to further enhance the near-infrared detection efficiency of silicon-based SPAD and move its detection range toward long waves,this article introduces the design of SPAD with black silicon materials.The equivalent refractive index and extinction coefficient of black silicon was obtained by studying the surface morphology,spectral absorption characteristics,and experimental test results.Based on this,an optical simulation model of black silicon was established.At the same time,the feasibility of the simulation model was verified by comparing the experimental data and simulation results of the PIN photodetector based on black silicon.Based on this,the design and simulation research of SPAD based on black silicon is carried out.Simulation results show that the introduction of black silicon materials can significantly improve the near-infrared detection efficiency of silicon-based avalanche photodiodes and extend their detection range to the long-wave direction.