Normally‐off GaN‐MISFET with well‐controlled threshold voltage

A new device structure with four epitaxial layers and a recessed gate is proposed for normally‐off operation in GaN‐FETs. Employment of this structure makes it possible to control accurately the threshold voltage without accurate control of recess etching depth. The high breakdown voltage and the low on‐resistance of the fabricated devices are also reported. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)