A New Structure and Process Method for SiC Trench MOSFET

In this paper, we propose a new device structure, fabrication process, and TCAD simulation for a SiC Trench MOSFET. Through utilizing a trench refill process with a controlled flow rate of hydrogen chloride (HCl) gas reported before, we can achieve a thin lateral thickness in the p-connect layer and a new structure of SiC Trench MOSFET, without using ion implantation. When the device is under reverse bias, the parasitic PMOS turn-on effectively clamps the p-connect and p-bottom regions, providing robust protection for the gate oxide corners. TCAD simulation reveals that the lateral thickness of the p-connect layer should be maintained below 400Å. The SiC Trench MOSFET demonstrates the capability to block a reverse bias voltage of 1174V, with the n-drift layer having a minimum thickness of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$7\mu\mathrm{m}$</tex> beneath the p-bottom region.