Novel Approach Toward Body Diode Reverse Recovery Performance Improvement in Superjunction MOSFETs

In this paper, a novel superjunction MOSFET with ohm contact in the termination region and dual Schottky contacts in the cell region is proposed and experimentally demonstrated. The dual Schottky contacts consisting of the N-type Schottky contact and the P-type Schottky contact suppress the hole injection in the cell region, thereby reducing the reverse recovery charge and enhancing the current density in the termination region. The high current density and the ohm contact in the termination region provide sufficient slowly extracted non-equilibrium holes during the reverse reduction period, which contributes to a significantly improved softness. Experimental results show that, in comparison with the conventional superjunction MOSFET, 66.2% reduction in reverse recovery charge and 137.5% improvement in softness factor can be obtained in the proposed superjunction MOSFET.