A New Model for Avalanche Build-Up of Carriers in a SAGCM Avalanche Photodiode

A new model for the avalanche build-up of carriers in an avalanche photodiode (APD) including the dead-space effect has been developed and used to study the frequency response of a resonant-cavity-enhanced (RCE) separate absorption, grading, charge, and multiplication (SAGCM) APD. In this model, the carriers are characterized by their energy and position in the region of multiplication. The excess energy of the carriers above threshold are assumed to be equally distributed among the carriers after impact ionization. The results are demonstrated with a $\hbox{In}_{0.1}\hbox{Ga}_{0.9}\hbox{As/Al}_{0.2}\hbox{Ga}_{0.8}\hbox{As}$ RCE APD and good agreement was obtained from comparisons with the published experimental data for gain-bias and bandwidth-gain plots.