Non-quasi-static transient and small-signal two-dimensional modeling of GaAs MESFET's with emphasis on distributed effects

The operation of micron and submicron GaAs MESFETs under high-speed transient and high-frequency small-signal conditions is analyzed using a two-dimensional model. The effects of displacement currents, dipole due to negative differential mobility or current continuity, and two-dimensional transport are emphasized. The origin of delay effects, such as the phase delay incorporated in small-signal models, is explored in order to relate it to the behavior under switching conditions. Broadband expressions for the extraction of a complete small-signal model are presented. Using the expressions derived, the variation of model elements with frequency and the effect of this on the unilateral gain of the device are studied.>