Investigations of AlGaN/AlN/GaN MOS-HEMTs on Si Substrate by Ozone Water Oxidation Method

Al0.3Ga0.7N/AlN/GaN metal-oxide-semiconductor high electron mobility transistors (HEMTs) grown on Si substrates by using ozone water oxidation method are investigated. Superior improvements of 52.2% in two-terminal gate-drain breakdown voltage (BVGD), 30.3% in drain-source current density (I-DS) at V-GS = 0 V (I-DSS0), 43.6% in maximum I-DS (I-DS,I- (max)), 34.7% in maximum extrinsic transconductance (g(m, max)), and 52.7%/34.3% in unity-gain cutoff/maximum oscillation frequency (f(T)/f(max)) are achieved as compared with a reference Schottky-gated HEMT. Thermal stability is studied by conducting temperature-dependent characterizations of devices at ambient temperatures of 300-550 K. Time-dependent electrical reliability analyses for the devices stressed in off-state (V-GS = -20 V and V-DS = 0 V) for 0-60 h and on-state (V-GS = 2 V and V-DS = 20 V) for 0-20 h are also made to physically investigate the dominant degradation mechanisms. Excellent reliability and thermal stability at 300-550 K are achieved by the present design.