10 A/950 V switching of GaN-channel HFETs with non-doped AlN buffer

Abstract

AlN-based semiconductor devices are considered to outperform lateral AlGaN/GaN HFETs for power-electronic switching applications due to the high AlN-material breakdown field strength. We present an AlGaN/GaN /AlN-HFET transistor without any compensation doping in the AlN-buffer layer. Breakdown voltage scaling as function of the gate-drain separation of 140 V/µm and power figure-of-merit of 2.4 GW/cm2 were achieved which is superior to most other GaN device technologies. 120 m Ω power transistors demonstrated 10 A switching transients up to 950 V off-state voltage and thus meet basic requirements for kW-range power switching. The origin of still present dispersion effects during high voltage switching could be attributed to a high structural defect density at the AlN-buffer / GaN channel material interface.