Superior pinch-off characteristics at 400 degrees C in AlGaN/GaN heterostructure field effect transistors

AlGaN/GaN field effect transistors have been fabricated on SiC(0001) substr ates, and the I-V characteristics in the devices have been examined from ro om temperature to 400 degrees C. In addition to excellent current saturatio n characteristics, sufficient pinch-off characteristics have been obtained up to a temperature of 400 degrees C for the first time, as the result of r educed crystal defects and reduced etching damage in the devices. The tempe rature dependence of the transconductance has been also examined. The degra dation rate in the transconductance has been proved to be low above 300 deg rees C: the transconductance degraded by only 8% for a temperature increase from 350 to 400 degrees C. Sufficient pinch-off characteristics and a rela tively low degradation rate in the transconductance ensure the practical us e of the devices at high temperatures.