  III-V material based digital alloy Avalanche Photodiodes (APDs) have recently
been found to exhibit low noise similar to Silicon APDs. The III-V materials
can be chosen to operate at any wavelength in the infrared spectrum. In this
work, we present a physics-based SPICE compatible compact model for APDs built
from parameters extracted from an Environment-Dependent Tight Binding (EDTB)
model calibrated to ab-initio Density Functional Theory (DFT) and Monte Carlo
(MC) methods. Using this approach, we can accurately capture the physical
characteristics of these APDs in integrated photonics circuit simulations.
