Understanding the cause of IV kink in GaAs MESFETs with two-dimensional numerical simulations

High performance GaAs MESFETs have been observed to exhibit kinks in their IV characteristics, particularly when high drain-source voltages are applied, Such characteristics make the design of circuits with high operating voltages difficult since this type of IV anomaly is typically not modeled by circuit simulators. This work has identified the cause of these kinks through the use of two-dimensional numerical device simulation with impact ionization. These simulations have also identified a potential device solution to IV kink. Furthermore, the results of this simulation work were verified by comparison with fabricated devices.