1200 V Fully-Vertical GaN-on-Si Power MOSFETs

We report 1200 V fully-vertical GaN-on-Si trench MOSFETs with fluorine implanted termination (FIT-MOS). The FIT region with negative fixed charges becomes resistive and naturally isolates the discrete devices, replacing the conventional mesa etching termination (MET), eliminating the electric field crowding effect at the mesa edges, therefore boosting the breakdown voltage of the FIT-MOS to 1277 V from 567 V of the MET-MOS. Moreover, the as-fabricated FIT-MOS exhibits a threshold voltage (V_TH) of 3.3 V, an ON/OFF ratio of ~10⁷, together with a specific onresistance (R_on,sp) of 5.6 mΩ·cm². These results show great potential of cost-effective GaN-on-Si vertical transistors for kV-class applications.