Avalanche characteristics of single heterojunction avalanche photodiodes

A simple Monte Carlo (MC) model is proposed to study the avalanche characteristics of heterojunction avalanche photodiode (HAPD). This model is capable to simulate the avalanche multiplication and excess noise factor in HAPDs by including the dead-space effect, hole to electron ionization ratio and heterointerface probability. The dead-space effect showed a vital role in reducing noise in single junction HAPDs based on the statistical determination in our model. It is shown that the dead-space effect reduces the avalanche noise in heterojunction device due to the localized ionization events. We found that the dead-space effect and the number of hole feedback impact ionizations are still the dominant effects to improve the excess noise factor especially in the injection layer of the device. In addition, the probability of electron and hole to cross the heterointerface will eliminate the secondary impact ionizations in the device.