A technique for calculating parameters of a small-signal equivalent circuit of microwave variband-emitter heterojunction bipolar transistors based on the quasi-hydrodynamic model of electron transport

A nonlinear system of differential equations is proposed which describes the one-dimensional active region of a transistor operating in the static mode. The system consists of a quasi-hydrodynamic model of electron transport, similar in form to the drift-diffusion model, a drift-diffusion model of hole transport, and electric-field equations. A technique for calculating six parameters of the small-signal equivalent circuit of the active region from five solutions to this system is developed. The static current-versus-voltage characteristics and equivalent-circuit parameters of a GaAs/AlGaAs heterojunction bipolar transistor calculated by this technique are presented.