S-parameter simulation of HBTs on gallium arsenide

We present two-dimensional simulations of one-finger power Heterojunction Bipolar Transistors (HBTs) on GaAs. Several important physical models are discussed. We demonstrate good agreement of simulations of four different types of devices with measured data in a wide temperature range. In addition, we were able, by accounting properly for self-heating, to simulate correctly the output device characteristics. Finally, we simulated S-parameters with our two-dimensional device simulator at 5 GHz and calculated them for the range from 0 to 20 GHz using a T-like eight element small signal equivalent circuit. A comparison of simulated and measured S-parameters is presented in the paper.