Al0.65Ga0.35N/Al0.4Ga0.6N Micro-Channel Heterojunction Field Effect Transistors With Current Density Over 900 mA/mm

We report on the demonstration of high current density in Al
_0.65
Ga
_0.35
N/Al
_0.4
Ga
_0.6
N heterojunction field effect transistors with micro-channels enabled by enhanced contact injection. Devices with a gate length of 100 nm exhibited a maximum current density of 910 mA/mm and a maximum transconductance of 140 mS/mm. A current gain cut off frequency of 20 GHz and maximum oscillation frequency of 36 GHz were obtained. Large-signal load-pull characterization of the transistors showed output power density of 2.7 W/mm at 10 GHz. The current density and output power density represent the state-of-art performance for high Al-composition AlGaN channel transistors.