CIMOSFET: A New MOSFET on SiC with a Superior Ron·Qgd Figure of Merit

A new MOSFET structure named the CIMOSFET (Central Implant MOSFET) has been presented and experimentally confirmed on SiC. The novelty of the CIMOSFET lies in a p-type implant introduced in the middle of the JFET area to shield the oxide interface field from the drain bias. Compared to the commercially available 1200 V SiC DMOSFET, this new concept has significantly reduced the on-resistance (Ron) and gate-drain capacitance (Cgd) simultaneously, produced a record low Ron·Qgd Figure of Merit of 455 mΩ·nC at 25°C, and 700 mΩ·nC at 150°C (~30% of the best data found). Only a 55% increase in Ron from 25°C to 150°C has been achieved due to the highly doped drift layer used on the CIMOSFET. Inductive load switching measurements have shown the CIMOSFET exhibits a fast switching performance. The CIMOSFET blocks 1600 V even though its drift doping is higher than that of the conventional DMOSFETs.