The Research Of Silicon Avalanche Photodiodes On Monte Carlo Methods

With the development of science,people’s production life is increasingly inseparable from optical communication,so the highly sensitive and low jitter silicon avalanche photodiodes are widely used in military,civil and medical fields such as laser guidance,LIDAR,medical detection.Among them,avalanche breakdown probability and time resolution as the key parameters of silicon avalanche photodiodes,directly determine the detection accuracy of the device,so how to design high avalanche breakdown probability and high time resolution of the avalanche photodiodes has become a top priority in the industry.In order to study the physical mechanism affecting the avalanche breakdown probability and time resolution,this paper adopts Monte Carlo method to simulate the devices with different electric field structures and obtain the main factors affecting the avalanche breakdown probability and time resolution through the analysis of carrier collision behavior in the avalanche multiplication region.The details of the study are as follows.1.Using Monte Carlo method,a simulation platform based on C++is constructed,which can simulate the key parameters of carrier phonon scattering and avalanche collisions of pn junctions with different doping concentrations.The mean free path and scattering number of carriers are analyzed,and the mean free path and collisional ionization scattering number are obtained to increase with the electric field strength.The steep electric field leads to an increase in the energy gain efficiency of the carriers,which shortens the time interval for the collisional ionization scattering of carriers,reduces the probability of lattice vibration scattering occurrence and shortens the avalanche build up time,thus improving the time resolution.2.The simulation compares the avalanche breakdown probability and time resolution of p-on-n and n-on-p structure devices at different wavelengths,and obtains the law that the avalanche breakdown probability and time resolution of p-on-n structure decrease with increasing wavelength,and the avalanche breakdown probability and time resolution of n-on-p structure increase with increasing wavelength.