Investigation and Improvement on Surge Robustness of Double-Trench SiC MOSFETs in Synchronous Rectification Mode

This paper investigates the surge capability of double-trench SiC MOSFETs under both synchronous and asynchronous rectification mode. The results indicate that in synchronous rectification mode, the terminal region fails before the cell region, which weakens the surge capability of the device. An improved surge spice model and thermal simulation model confirms that heat is concentrated in the terminal region because the conduction of the channel can suppress the activation of the body diode under positive gate bias. Subsequently, this paper utilizes TCAD simulation to optimize the device design by increasing the source trench depth to balance the surge temperatures in the terminal region and the cell region, thus achieving a compromise between surge capability and forward conduction performance.