A new super-junction VDMOS realizing fast reverse recovery

In this paper, the authors propose a new Super-Junction VDMOS structure to realize fast reverse recovery of its body diode. In the proposed SJ-VDMOS, the P-pillar of the drift region is surrounded by a thin SiO₂ which prevents the injection of electrons from both the drain and the N-pillar region into the P-pillar region. Thus the stored charges are reduced. A diode D₀ integrated outside the edge terminal is used to conduct the electrons collected at the interface of the bottom polysilicon/SiO₂ generated during the turning-off state of the VDMOS to prevent pre-breakdown. Besides, a Schottky diode in parallel with the body diode is also integrated to further reduce the reverse recovery charges (Q_rr). Simulation results show that the proposed SJ-VDMOS obtains the lowest Q_rr = 54 nC without any lifetime control which reduces the total switching power loss in an invertor system to about 48 μJ for a 500 V SJ-VDMOS @ I = 1.6 A.