Strain induced buffer layer defects in GaN HFETs and their evolution during reliability testing

The reliability physics of GaN HFETs has been investigated in order to identify strain related traps originating at the GaN/SiC substrate interface. The buffer layers investigated were deposited by MBE techniques at a series of growth temperatures and thicknesses so as to attain buffer layers with variable trap density. Heterojunction transistors (HFETs) based on AlGaN/GaN heterostructures have been modeled and the results are described in this paper.