Abstract

In this paper a semiempirical capacitance model of GaAs FET, very useful for CAD of MMIC, is proposed. The model fits the results of two dimensional (2-D) simulations of device behaviour, accounting for the most important microwave effects, by means of the determination of an effective shape of the depletion region in the active channel. Simple physical equations and a few effective empirical parameters, with a precise physical meaning, are employed. So the initial estimation of parameters and their extraction procedure result to be very easy. In spite of its semiempirical nature the model does not leave the control over physical and technological device parameters to circuit designer, necessary to achieve a reliable design. The model usefulness and accuracy are experimentally confirmed to be very satisfactory for different kinds of MESFETs.