3.3-kV-Class 4H-SiC MeV-Implanted UMOSFET With Reduced Gate Oxide Field

A critical issue for SiC trench gate metal–oxide–semiconductor field-effect transistors (UMOSFETs) is gate oxide shielding from the electric field at the trench bottom. In this letter, low ON-resistance with low gate electric field was achieved in a 3.3-kV-class UMOSFET with a unique hexagonal buried p-base region formed by MeV ion implantation. The shielding effect was further enhanced by a self-aligned trench bottom shielding region. The specific ON-resistance, with and without the trench bottom shielding region, was 8.3 and 9.4 $\text {m}\Omega \text {cm}^{2}$ , respectively. The blocking voltage in each case was $\sim 3800$ V. The electric field in the gate oxide with the trench bottom shielding region was reduced to 2.5 MV/cm at 3300 V.