High-Performance 500 V Quasi- and Fully-Vertical GaN-on-Si pn Diodes

Abstract

This letter demonstrates quasi- and fully vertical GaN-on-Si pn diodes with record performance. The optimized device structure employs a highly conductive (N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</sub> >10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">20</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> ) current collecting layer and a lightly carbon-doped drift layer. With this optimization, a differential specific on-resistance (R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</sub> ) of 0.8-1 mΩ·cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , a breakdown voltage (BV) over 500 V, and a high forward current (~kA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) were demonstrated. Excellent R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</sub> and BV performance up to 300 °C were also obtained. A small reverse recovery time of 50 ns was demonstrated under switching conditions. With Baliga's figure of merit over 0.32 GW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , these devices show the great potential of low-cost GaN-onSi vertical devices for future power applications.