Large signal characterization of heterojunction bipolar transistors

A large signal Eber-Moll model for the analysis of an AlGaAs/GaAs heterojunction bipolar transistor (HBT) is presented. The parasitic elements of the equivalent circuit are extracted from the S-parameter measurements under cutoff bias conditions. A semi-analytical approach is used to extract the intrinsic parameters of the small signal equivalent circuit. The equivalent circuit clement parameters are evaluated from the frequency dependent scattering parameters measured under multiple bias. Only a few elements were evaluated from the numerical optimisation. Appropriate equations given by device physics are fitted to the bias variation of intrinsic parameters so that the large signal parameters can be extracted.