Comparative Study of SiC Planar MOSFETs With Different p-Body Designs

Abstract

Silicon carbide MOSFET has been commercialized for many years. Its performance is still improving especially for high-frequency application. High-frequency figure-of-merit (HF-FOM) ${R}{ \mathrm{\scriptstyle ON}}^\ast {C}_{\text {GD}}$ and ${R}_{ \mathrm{\scriptscriptstyle ON}}{}^\ast ~{Q}_{\text {GD}}$ were used for a comprehensive evaluation of the performance of MOSFET. In this article, SiC planar MOSFETs with different p-body designs were comparatively studied. A new planar MOSFET with buffered gate and thick central oxide gate structure (TCOX-MOS) was proposed to further improve the gate oxide electric field in OFF-state and HF-FOM. Compare to the conventional planar MOSFET (C-MOS), the maximum gate oxide electric field, gate–drain charge, and HF-FOM ( ${R}_{ \mathrm{\scriptscriptstyle ON}} {}^{\ast } {Q}_{\text {GD}}$ ) of TCOX-MOS are 32%, 83%, and 84% lower, respectively. Furthermore, TCOX-MOS shows less short-channel effects by better channel shielding structure. The results show that TCOX-MOS is a more attractive device structure.