Enhancement-Mode InAlN/GaN MISHEMT with Low Gate Leakage Current

We report an enhancement-mode InAlN/GaN MISHEMT with a low gate leakage current by a thermal oxidation technique under gate. The off-state source-drain current density is as low as ~10?7 A/mm at VGS = 0 V and VDS = 5 V. The threshold voltage is measured to be +0.8 V by linear extrapolation from the transfer characteristics. The E-mode device exhibits a peak transconductance of 179 mS/mm at a gate bias of 3.4 V. A low reverse gate leakage current density of 4.9 ? 10?7 A/mm is measured at VGS = ?15 V.