Enhancement-mode GaN-on-Silicon MOS-HEMT using pure wet etch technique

This paper reports for the first time a gate-recessed GaN-on-Silicon MOS-HEMT device with true normally-off operation and high breakdown voltage using a one step simultaneous oxidation/dissolving treatment by hybrid alkaline solution with hydrogen peroxide and potassium hydroxide. After 40-min wet etching at 95 ^oC solution temperature, the Al₂O₃/GaN MOS-HEMT device features a true normally-off operation with a threshold voltage of 3 V, extracted by the linear extrapolation of the transfer curve. Combined with the three-terminal off-state breakdown voltage up to 1492 V for the device with 28 μm gate-to-drain distance, this technique manifests an easy, stable and low cost approach for the commercialization of normally-off GaN power devices.