Study of frequency and time responses of a separated absorption and multiplication region avalanche photodiode

In this paper, the frequency and time responses of a separated absorption and multiplication avalanche photodiode are studied by solving the carrier continuity equations, in the low gain regime. The discrepancy between the carrier velocities in different layers is considered for the first time. It is shown that considerable error occurs, if the device d characteristics are calculated assuming uniformly distributed velocities in the depletion layer, especially when the different layers have almost equal thickness