Impact Ionization Engineering Design And Noise Characteristics Of ?-? Avalanche Photodiodes

The development of photoelectron device provides convenience for people's life.Photodetector is an important part of photoelectron device.Avalanche photodetector(APD)is the most widely used photodetector.APD has higher signal-to-noise ratio and higher sensitivity compared with the photodetector without internal gain.Therefore,the development and research of APD is a main study direction of photoelectric detector.The main factors that restrict the performance of APD are the dark current and the excess noise caused by the its internal gain.In this paper,we study the working principle and characteristic parameters of APD by using InGaAs/InP APD model with SACGM structure,and design a new kind of low noise In P APD.The details include:(1)The InGaAs/InP APD physical model of SACGM structure is established by using semiconductor simulation software SILVACO TCAD,and the physical mechanism,working principle and structure parameters of APD are studied,including the distribution of electric field inside the device,the characteristics of dark current,the punch through voltage and the breakdown voltage of the device,etc.,the relationship between the device characteristics and the structure parameters is obtained,which provides guidance for the following design.(2)The generation process of APD gain and noise is studied in detail,and the methods of reducing noise are discussed.The physical mechanism of APD noise and gain is simulated by means of numerical calculation,and the mechanism of reducing excess noise is analyzed and calculated.At the same time,the reason of low noise of APD with special heterostructure is studied,and the noise characteristic of the device is further analyzed by numerical simulation.(3)Based on the simulation results,an In P-based avalanche photodiode with special design multiplication region is proposed.The double charge layer and double multiplication layer structure of APD are designed by using impact ionization engineering(I~2E),by inserting different materials of ionization threshold energy into the multiplication region,the ionization threshold energy is graded in the multiplication region to control the ionization position and reduce the noise.The design of the device modeling calculation,and give a complete simulation results,obtained high-performance low-noise APD.