Investigations of AlGaN/AlN/GaN MOS-HEMTs on si substrate by ozone water oxidation method

Al_0.3Ga_0.7N 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 (BV_GD), 30.3% in drain-source current density (I_DS) at V_GS=0VIDSS0), 43.6% in maximum I_DS(I_DS,\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.