Distributed modeling of switching transients in GaAs MESFET's

The transient phenomena resulting from the application of a step bias at the gate electrode of a GaAs MESFET have been simulated using a two-dimensional model. Results emphasizing the effects of the displacement current in high-speed devices are presented. The causes of the delay are discussed for devices of different gate lengths, and the effects of the distributed gate capacitance and the related delay in the drain current characteristics are incorporated in an equivalent circuit model. Analytical expressions derived from large-signal analysis are shown to conform with the results of two-dimensional simulation, allowing for an implementation in simulators such as SPICE.<
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