A New Cell Topology for 4H-SiC Planar Power MOSFETs and Comparison with Hexagonal and Octagonal Cell Topologies

A new Dodecagonal (polygon with twelve sides, short for Dod) cell topology is designed for 4H-SiC planar power MOSFETs. The Dod cell is used in the layout design of the 650 V SiC MOSFETs. The nominal Hexagonal (Hex) cell and a recently published Octagonal (Oct) cell are also used on the 650 V SiC MOSFET layout designs for comparisons. The devices are fabricated, diced, and packaged for static and dynamic characterizations. Experimental results show that the Hex-cell MOSFET has the lowest specific ON-resistance (Ron,sp) and is suitable for high-power applications. The Dod and Oct-cell MOSFETs have much smaller gate-drain capacitance than Hex-cell MOSFETs, making them good candidates for high-frequency applications. The new Dod cell is designed with optimized channel density to have reduced Ron,sp compared to the Oct cell.