Study of Hybrid Schottky – Ohmic Source and Drain AlGaN/GaN HEMTs for Low Noise Application

In this study, AlGaN/GaN high-electron mobility transistors (HEMTs) with hybrid Schottky-ohmic source and drain structures were fabricated for low noise applications. The transconductance was improved due to the Schottky metal extension. Furthermore, the device achieved higher f<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</inf> and f<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</inf>, reaching 72.6 GHz and 162 GHz, with lower extracted parasitic resistance. At 28 GHz, the device demonstrated excellent NF<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">min</inf> of 1.51 dB. These results confirm that the AlGaN/GaN HEMT with a hybrid source and drain offers great potential for outstanding low noise performance in Ka-band applications.