High temperature characteristics of GaAs MESFET devices fabricated with AlAs buffer layer

We have investigated the influence of AlAs buffer layers on MESFET drain leakage current at temperatures from 25-350/spl deg/C. The experimental results show that subthreshold drain leakage current is substantially decreased with increasing AlAs layer thickness. For a 1 μm×200 μm MESFET with 2500 /spl Aring/ of AlAs buffer layer, we have obtained 78 μA of subthreshold drain leakage current at 350/spl deg/C ambient temperature. This leakage current value is a factor of 2.5 improvement over the best previously reported results at 350/spl deg/C.