Two-dimensional Simulation Of GaAs MESFETs Including Impact Ionization Of Carriers And Carrier Trapping In The Semi-insulating Substrate

Abstract

To understand the drain-to-source breakdown mechanism in GaAs MESFETs is important for realizing high-performance GaAs LSIs, but it has not been well clarified. Recently, an abrupt increase in output conductance with the drain voltage (kink) is often reported experimentally, and sidegating effects become remarkable in this region(1). This suggests that when interpreting the o r the breakdown, effects of carrier trapping in the semi-insulating substrate should be considered. Some theoretical works on the breakdown have been made and one of them simulates I-V curves by considering impact ionization(21, but it neglects carrier trapping by deep levels in the substrate. So, in this work, we have mode 2-D simulation of GaAs MESFETs in which impact ionization of carriers and deep levels in the semi-insulating substrate are considered, and have found that the kink is explained by impact ionization of carriers and the following carrier trapping in the substrate.