Numerical Simulation of Neutron Radiation Effects in Avalanche Photodiodes

A new one-dimensional (1-D) device model developed for the simulation of neutron radiation effects in silicon avalanche photodiodes is described. The model uses a finite difference technique to solve the time-independent semiconductor equations across a user specified structure. The model includes impact ionization and illumination allowing accurate simulation with minimal assumptions. The effect of neutron radiation damage is incorporated via the introduction of deep acceptor levels subject to Shockley-Read-Hall statistics. Preliminary analysis of an EG&G reverse APD structure is compared with experimental data from a commercial EG&G C30719F APD.