Photoionisation spectroscopy of traps in AlGaN/GaN high electron mobility transistors grown by molecular beam epitaxy

Photoionisation spectroscopy has been carried out in bias-stressed AlGaN/GaN high electron mobility transistors grown by MBE in order to probe the nature of the deep trapping centres responsible for stress-induced current collapse in these devices. The results indicate that a GaN buffer layer trap previously associated with current collapse in devices grown by MOCVD is responsible for induced collapse in MBE-grown structures.