The 1.6-kV AlGaN/GaN HFETs

Abstract

The breakdown voltages in unpassivated nonfield-plated AlGaN/GaN HFETs on sapphire substrates were studied. These studies reveal that the breakdown is limited by the surface flashover rather than by the AlGaN/GaN channel. After elimination of the surface flashover in air, the breakdown voltage scaled linearly with the gate-drain spacing reaching 1.6 kV at 20 mum. The corresponding static ON-resistance was as low as 3.4 mOmegamiddotcm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . This translates to a power device figure-of-merit V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BR</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</sub> =7.5times10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">8</sup> V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> middotOmega <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> , which, to date, is among the best reported values for an AlGaN/GaN HFET