Impact of the transition region between active area and edge termination on electrical performance of SiC MOSFET

The transition region between the active area and the edge termination of silicon carbide (SiC) MOSFET is either used to place a poly-silicon gate runner (G-MOS) or electrically contacted to the source potential (S-MOS), which is studied experimentally and by TCAD simulation in this work. The simulation results indicate that the transition region of G-MOS can effectively alleviate the propagation delay in the poly-silicon gate and allow all elementary cells to turn on quickly at the same gate voltage magnitude, which leads to a lower on-resistance (Ron), and small switching delay time. On the other hand, the transition region of G-MOS increases the Miller capacitance (Cgd), which can be reduced by shortening the length of the transition region. The simulation results are further validated by the experimental values, which show a reduction of Ron of G-MOS by 212% and an increase of Cgd of G-MOS by 72% compared to S-MOS. Moreover, the transition region barely influences the breakdown voltage of the devices, which are both higher than 1700 V.