RF High-Power Operation of AlGaN/GaN HEMTs Epitaxially Grown on Diamond

Abstract

We epitaxially grow AlGaN/GaN high-electron-mobility transistors (HEMTs) on IIa-type single-crystal diamond (111) substrates. A 0.4-μm gate-length HEMT showed a dc drain-current density <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS</sub> of 770 mA/mm and a breakdown voltage of 165 V. In the RF large-signal measurements at 1 GHz, an RF output-power density <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OUT</sub> of 2.13 W/mm was obtained. This is the first report of RF power operation of AlGaN/GaN HEMTs epitaxially grown on diamond. The AlGaN/GaN HEMTs epitaxially grown on diamond showed a low thermal resistance of 1.5 K·mm/W.