Normally‐off AlGaN/GaN MOSHFETs with HfO2 gate oxide

Normally‐off AlGaN/GaN MOSHFETs with a thick HfO2 as a gate oxide have been fabricated. The HfO2 with a thickness of 100 nm was deposited by pulsed‐laser deposition. The threshold voltage was 3 V and the maximum drain current was 730 mA/mm at a gate voltage of 10 V. The maximum transconductance was 185 mS/mm, which was about 8 times larger than that of the GaN MOSFETs. The field effect mobility was 900–1500 cm2/Vs, which is also higher than that of the GaN MOSFETs. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)