The Impact of the Hexagonal and Circular Cell Designs on the Characteristics and Ruggedness for 4H-SiC MPS Diodes

In this article, SiC Merged PiN Schottky (MPS) diodes with hexagonal and circular cell designs are investigated and compared in terms of characteristics and ruggedness. It is demonstrated by experimental and simulated methods that the circular cell design brings better performance than the hexagonal one. Owing to the almost simultaneously triggering of the P+ island and the P+ ring of the circular cell under high current stress, the current distribution is more balanced, which significantly reduces forward voltage (
${V}_{F}$
) and lower energy-dissipated heat, and further enhances the surge current capability. Moreover, the circular shape can relieve the curvature effect and electric field crowding under reverse blocking conditions, thereby improving breakdown voltage (
BV
) and avalanche capability. These results suggest that circular cell design can be employed to improve the performance and ruggedness of the SiC MPS diodes.