A New Cell Topology for 4H-SiC Planar Power MOSFETs for High-Frequency Switching

Abstract

A new cell topology named the dodecagonal (a polygon with twelve sides, short for Dod) cell is proposed to optimize the gate-to-drain capacitance (Cgd) and reduce the specific ON-resistance (Ron,sp) of 4H-SiC planar power MOSFETs. The Dod and the octagonal (Oct) cells are used in the layout design of the 650 V SiC MOSFETs in this work. The experimental results confirm that the Dod-cell MOSFET achieves a 2.2× lower Ron,sp, 2.1× smaller high-frequency figure of merit (HF-FOM), higher turn on/off dv/dt, and 29% less switching loss than the fabricated Oct-cell MOSFET. The results demonstrate that the Dod cell is an attractive candidate for high-frequency power applications.

Keywords

• SiC power MOSFET
• cell topology
• dodecagonal cell
• octagonal cell
• gate-to-drain capacitance (C_gd)
• specific ON-resistance (R_on,_sp)