A 4H-SiC Superjunction MOSFET Design for High Gate Oxide Reliability

In this paper, a 4H-SiC superjunction trench metal-oxide-semiconductor field effect transistor containing a $\mathrm{P}^{+}$-shielding and a thick oxide layer(PD-SJMOS) is proposed. The P-pillar region and N-drift form an SJ structure, which reduces the specific on-resistance ($R_{\text {on}, \mathrm{p}}$) and increases the breakdown voltage ($B V$). The electric field strength of the oxide layer at the gate trench corner is reduced by the $\mathbf{P}$-shielding and thick oxide layer. And the switching speed of the device is improved by reducing the gate-drain overlap area. Compared with 4H-SiC superjunction trench MOSFET (T-SJMOS) and 4H-SiC superjunction trench MOSFET with $\mathrm{P}^{+}$-shielding (PT-SJMOS), the PD-SJMOS offers higher gate oxide reliability, better dynamic and static performance.