Improving the Surge Current Capability of SiC MOSFETs Under Positive Gate Bias

In SiC MOSFETs, the degradation of surge current capability when applying positive gate voltage has become a problem. To suppress the degradation of surge current capability, we conducted TCAD simulation to accurately understand the bipolar operation and heat generation inside the device during surge operation. Based on the results, we experimentally studied the improvement of device design and development of protection circuits. In device design, we showed that appropriate design of current spread resistance can improve surge current capability while minimizing the increase in on-resistance. We also studied protection circuits for surge operation by gate control and provided new guidelines for appropriate switching current and switching delay time.