GaN metal-oxide-semiconductor field-effect-transistor with atomic layer deposited Al2O3 as gate dielectric

We report on a GaN metal-oxide-semiconductor field-effect-transistor (MOSFET) using atomic-layer-deposited (ALD) Al2O3 as the gate dielectric. Compared to a GaN metal-semiconductor field-effect-transistor (MESFET) of similar design, the MOSFET exhibits several orders of magnitude lower gate leakage and near three times higher channel current. This implies that the ALD Al2O3/GaN interface is of high quality and the ALD Al2O3/GaN MOSFET is of interest and potential for high-power RF and digital applications. In addition, the channel mobility of n-GaN layer is ∼414 cm2/V s, which has not been degraded by ALD Al2O3 growth and device fabrication.