Fluorine-Implanted Termination for Vertical GaN Schottky Rectifier With High Blocking Voltage and Low Forward Voltage Drop

In this letter, fluorine-implanted termination (FIT) has been demonstrated in vertical GaN-on-GaN Schottky barrier diodes (SBDs). Owing to the unique feature of F ions that can become negative fixed charges in GaN, the electric field crowding at the junction edge can be mitigated and the breakdown voltage (BV) of the vertical GaN SBDs can be effectively enhanced. For SBDs, it is challenging to simultaneously achieve both high BV and low forward voltage drop (V
_F
). Thanks to the effective leakage suppression by FIT, a high BV of ~800 V is realized in an FIT-SBD even with a low V
_F
value of 0.85 V (at 100 A/cm
²
). By incorporating an AlGaN tunneling-enhancement layer, the FIT-SBD can achieve further improved BV of ~1020 V and V
_F
of 0.83 V. Fast reverse recovery performance has also been realized in the FIT-SBDs.