Effects of Grounding Bottom Oxide Protection Layer in Trench-Gate SiC-MOSFET by Tilted Al Implantation

A trench gate SiC-MOSFET with BPW grounded by tilted Al implantation is developed in order to optimize the cell design and process for grounding the BPW in a more simple manner. From evaluation of static characteristics, the MOSFETs with sidewall region can improve the trade-off relationship between Ron,sp and Vbd by the variation of dSRs, and is superior than that of conventional BPW ground contact structure. From evaluation of dynamic characteristics, the MOSFETs with sidewall region can realize stable p-type ohmic contact for BPW compared with conventional BPW ground contact structure. Furthermore, the trade-off between Ron,sp and tsc of this device is adjusted to optimized layout of the p-type sidewall regions without degradation of the dV/dt dependence of turn-on and turn-off losses.