Design and Distributed Computer Simulation of Thin p~+-i-n~+ Avalanche Photodiodes Using Monte Carlo Model

摘要

The output current of an avalanche photodiodes (APD's) fluctuates in the absence of light as well as in its presence. The noise in APD's current arises from three sources: randomness in the number and in the positions at which dark carrier pairs are generated, randomness in the photon arrival number, and randomness in the carrier multiplication process. A Monte Carlo model has been used to estimate the excess noise factor in thin p~+-i-n~+ GaAs avalanche photodiodes. As this approach is computation intensive, simple parallel algorithm considering heterogeneous cluster based on MPICH was designed and implemented. Very good performance gain was achieved. It was found that APD model provides very good fits to the measured gain and noise and as such provides an accurate picture of the device operation. In this way, various device structures can be analyzed prior to their experimental realization. Through "computer experiments" like this outlined here, the effect of various geometries and material compositions on device performance can be assessed and optimal designs achieved.