Abstract

Transcapacitances and bias dependent total time delay and base resistance expressions for accurate modeling of heterojunction bipolar transistors (HBTs)are proposed.Small-signal equivalent circuit parameters are first extracted over the entire forward bias region using multi-bias S-parameter measurements.Relations taking into account the variation of the bias dependence of circuit elements on collector-emitter voltage and collector current are then developed.The resulting expressions are used to construct a large signal model,which is then tested and compared to a dedicated small-signal model and measurements.The developed expressions may be used to improve the accuracy of other large signal models.