Abstract The simulation of HgCdTe avalanche photodiode (APD) gains and excess noise factor is revisited through the development of a simplified Monte Carlo (MC) model, with the aim of a fast and accurate simulation enabling the design of improved APDs. In this first step, the model is based on a one-dimensional junction approximation with a constant electric field, in which electrons drift and gain energy while losing some of that energy by phonon emission, and where their impact ionization probability is evaluated at each time step. These simplifications allowed us to limit the model to six parameters, of which four were chosen to be adjustable as a function of APD cadmium composition, while the other two were fixed. After calibration, the model successfully matched the experimental gain characteristics of two APDs in the short-wave infrared (SWIR) and mid-wave infrared (MWIR), with simulation duration short enough to be compatible with design purposes. However, a unique set of parameters must be obtained to adjust the simulation to the excess noise factor. This indicates that the dependence of the impact ionization probability as a function of the electron energy is smooth, consistent with band structure calculation. Finally, the influence of the multiplication junction thickness on the APD characteristics was explored with our model, revealing an excess noise factor that is independent of the junction width.
Guerra et al. (Mon,) studied this question.