An Ultra-Low Gate Charge Shield Gate MOSFET with Pinch-Off Region and Schottky Contact

A novel low gate charge $(\mathrm{Q}_{\mathrm{g}})$ vertical power MOSFET (VDMOS) based on high-doped pinch-off region and stepped trench shield gate is proposed in this work. The easy-depleted pinch-off region not only functions as a series depletion capacitance connected to the drift region, but also introduces lateral coupling effect with P-body and shield plate. Combination of the two leads to a great reduction in $\mathrm{C}_{\mathrm{gd}}$ . Besides, the metal plug of trench shield gate realizes an integrated Schottky contact without additional area, improving reverse recovery performance. Simulation and modeling are presented to evaluate the $\mathrm{C}_{\mathrm{gd}}$ shielding effect and reveal internal mechanism. Compared with conventional shield gate trench (SGT) device, $\mathrm{Q}_{\mathrm{gd}}$ and $\mathrm{Q}_{\mathrm{g}}$ are reduced by 65% and 59%, and $R_{on,sp}\cdot \mathrm{Q}_{\mathrm{g}}$ achieves a decrease of 53%.