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

Al
_0.3
Ga
_0.7
N/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
= 0 V (I
_DSS0
), 43.6% in maximum I
_DS
(I
_DS,max
), 34.7% in maximum extrinsic transconductance (
gm
,max), and 52.7%/34.3% in unity-gain cutoff/maximum oscillation frequency (
fT
/
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.