AlGaN/GaN metal-oxide-semiconductor high electron mobility transistor with liquid phase deposited Al₂ O₃ as gate dielectric

The performance of n-GaN/AlGaN/GaN metal-oxide-semiconductor high electron mobility transistors (MOSHEMTs) with a 20 nm thick Al₂ O₃ gate oxide deposited using the low temperature liquid phase deposition technique is demonstrated. MOSHEMTs exhibit a 23% increase in saturation drain current density, 13% higher extrinsic transconductance, and a lower gate leakage current of 3 orders of magnitude in comparison with high electron mobility transistors. The stability and the interface quality of Al₂ O₃ /n-GaN by this alternative process are discussed. The sheet carrier concentration and Hall mobility are also estimated from the channel conductance under the gate, which is comparable with those measured by the van der Pauw method before the device processing.