AlGaN/GaN HEMTs with thermal oxidation treatment for microwave power applications

AlGaN/GaN high electron mobility transistors (HEMTs) with thermal oxidation treatment (TOT) are found to exhibit very low gate leakage current (10^-7A/mm of gate periphery up to -20 V applied reverse gate bias) and high maximum extrinsic transconductance (180 mS/mm). The two-dimensional electron gas concentration increased obviously after the oxidation treatment. A current gain cutoff frequency (f_T) of 36 GHz and a maximum oscillation frequency (f_MAX) of 60 GHz are deduced from S-parameter measurements for transistors with a gate length of 0.4 μm. The high performance TOT AlGaN/GaN HEMTs are highly promising for microwave power amplifier applications in radar and communication systems.