Modelling of heterojunction bipolar transistors (HBTs) based on gallium arsenide (GaAs)

This work describes an approach for small signal modelling of GaAs-based he terojunction bipolar transistors (HBTs) for low-voltage/high-power applicat ion (i.e., V-ce = 3 V, J(c) =3 X 10(4) A/cm(2)). The parameter extraction p rocedure is discussed in detail. Furthermore, it is demonstrated that the m odel is fully scalable with respect to emitter area by comparison of simula ted and measured S-parameters in the frequency range from DC to 20 GHz. Bas ed on the small signal model, a nonlinear large signal model with the same II-type topology is proposed. It has a small number of parameters and consi ders self-heating, which is particularly important for HBTs. Parameter extr action is discussed and it is demonstrated by comparison of simulation and measurement that the model can accurately predict the DC characteristics of a HBT for ambient temperatures ranging from 20 to 100 degrees C. (C) 2000 John Wiley & Sons, Inc.