Analysis of substrate deep-trap effects on the turn-on characteristics in GaAs MESFETs

Abstract

Two-dimensional analysis of the turn-on characteristics of GaAs MESFETs is made in which deep donors "EL2" in the semi-insulating substrate and surface states are considered. It is found that abnormal current overshoot due to EL2 can be seen when the off-state gate voltage is deeply negative. This is because in such a case electrons are depleted also in the semi-insulating substrate in the OFF state, and the corresponding ionized EL2 density N/sub EL2//sup +/ around the channel-substrate interface can be much higher than in the ON state.