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.