The new two-dimensional electron gas base HBT (2DEG-HBT): two-dimensional numerical simulation

The bipolar/FET characteristics of the 2DEG-HBT are analyzed extensively by a two-dimensional numerical simulator based on a drift-diffusion model. For bipolar operations at high collector current densities, it is confirmed that the cutoff frequency f/sub T/ is determined mainly by the collector transit time of holes and by the charging time of the extrinsic base-collector capacitance C/sub bc//sup EXT/. The charging times of the emitter and base regions and the base transit time are shown to be negligible. A high cutoff frequency F/sub T/ (88 GHz) and current gain h/sub FE/