Al_0.65Ga_0.35N/Al_0.4Ga_0.6N Micro-Channel Heterojunction Field Effect Transistors With Current Density Over 900 mA/mm

Abstract

We report on the demonstration of high current density in Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.65</sub> Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.35</sub> N/Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.4</sub> Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.6</sub> 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.