Self-clamped P-shield 4H-SiC trench MOSFET for low turn-off loss and suppress switching oscillation

A novel 4H-SiC trench MOSFET with self-clamped P-region (SCP-MOS) is proposed. The breakdown voltage is boosted and switching oscillation is suppressed by introducing a lightly P-type doping concentration region (LP) and additional NCSL. P+ and NCSL form a new electric field modulation region that reduces the electric field at the bottom of the gate, resulting in a higher breakdown voltage for the device. Moreover, When V DS is small, the LP region links P-shield and P+ source region, the P-shield is clamped at a low potential, which effectively reduces the gate to drain capacitance ( C GD ). As V DS increases, the LP region is gradually depleted, causing the P-shield to transition into floating state, the potential in the P-shield region is raised. Consequently, the described characteristics facilitate achieving low turn-off losses and Surge voltage( V Surge ). SCP-MOS has 32 % lower surge voltage compared to GP-MOS and 85 % lower turn-off loss compared to FP-MOS. Overall, SCP-MOS can obtain better E OFF - V Surge trade-off.