Monte Carlo simulation of avalanche noise characteristics of type II InAs/GaSb superlattice avalanche photodiodes

Abstract

A Monte Carlo model, which takes account of the stochastic nature of carrier scattering during transportation, including impact ionization, is presented here. To verify the model, it is used to simulate the field dependent drift velocity of electrons transporting in the bulk InAs material. The results are consistent with the experimental data. Then, the model is applied to type II InAs/GaSb superlattice (SL) avalanche photodiode (APD) structure and the avalanche noise characteristics at 77 K is calculated for different wavelengths. Our results reveal that the long wavelength (LW) APD has a higher excess noise factor (F) than the mid wavelength (MW) counterpart, probably due to the fact that holes in the LW SLs are easier to cause the impact ionization. Generally, the F decreases with increasing the device length, except that the device length is very thin for a LW APD.