An analytical self-backgating GaAs MESFET model including deep-level trap effects

A self-backgating GaAs MESFET model which can simulate low-frequency anomalies has been developed by including deep-level trap effects which cause reduction of the transconductance and increase of the output conductance and the saturation drain current with the applied signal frequency. This model has been incorporated into PSPICE and includes a time-dependent I-V curve model, a capacitance model, a RC network describing the effective substrate induced capacitance and resistance, and a switching resistance providing device symmetry. An analytical capacitance model describes the dependence of capacitance on V/sub gs/ and V/sub ds/ and also includes the channel-substrate junction modulation by the self-backgating effect. Measured data correspond to simulations by this model of the low-frequency anomalous characteristics, voltage-dependent capacitances, and S-parameters of conventional GaAs MESFETs for linear and microwave circuit design.<>