Experimental Investigations of SiC MOSFETs under Short-Circuit Operations

The short-circuit capability of power MOSFETs is crucial for the fault protection. In this work, short-circuit ruggedness and failure mechanisms of SiC planar and trench MOSFETs are compared and analyzed. Single-event short circuit tests are demonstrated. Experimental results show that thermal effect and gate stress are the two important factors which result in performance degradation and damage of SiC MOSFETs under short circuit operations. High gate stress will lead to hot carrier injection effect as well as tunneling effect under strong perpendicular electric field. The high current density and electric field at Pwell/Ndrift junction cause a high junction temperature, eventually leading to device failure. A temperature limited single-event failure SOA and drive-voltage limited degradation SOA are demonstrated.