Abstract

Effects of surface states on kink phenomena in GaAs MESFETs are studied by two-dimensional (2-D) DC and transient sim-ulation including impact ionization of carriers. The Spicer's unified defect model is adoped for a surface-state model. It is shown that a kink in the DC current-voltage characteristics could arise due to a space-charge effect originated from impact ionization of holes and the follow-ing hole capturing by the surface traps. Tran-sient or dynamic simulation indicates that the trap-related kink phenomenon is a rather slow process.