Abstract

Numerical simulations of Heterojunction bipolar Phototransistor (HPT) were performed using a two-dimensional finite element program. These simulations are done on configurations of phototransistors which are realised in CNET Bagneux. Comparison between simulation and measurement was done for topside illumination and good agreement was found. Different incident directions of beam light were simulated to study their effects on frequency response of the phototransistor. For the configurations of transistor used in our work, it is found that the lateral illumination gives a better optical cut off frequency than the upside and the downside illuminations (72 GHz and 42 GHz respectively) for the same incident optical power.