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

This letter demonstrates quasi- and fully vertical GaN-on-Si pn diodes with record performance. The optimized device structure employs a highly conductive (N D >10 20 cm -3 ) current collecting layer and a lightly carbon-doped drift layer. With this optimization, a differential specific on-resistance (R ON ) of 0.8-1 mΩ·cm 2 , a breakdown voltage (BV) over 500 V, and a high forward current (~kA/cm 2 ) were demonstrated. Excellent R ON 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 2 , these devices show the great potential of low-cost GaN-onSi vertical devices for future power applications.