Abstract

For the first time microwave measurements at ambient temperatures up to 300°C have been performed on especially fabricated GaAs MESFETs, GaAs/AlGaAs HEMTs and HBTs, de­signed for continous operation at ambient temperatures up to 300°C with high reliability. A technology is presented which allows the realization of MESFET, HEMT and HBT device per­formance at elevated ambient temperatures. Ohmic and Schottky contacts have been realized with Ni-Ge-Au-Ni~W5-Si2-Au and LaB6-Au, respectively. These results open new possibilities for various applications of such transistors.