Static off state and conduction state charge imbalance in the superjunction power MOSFET

Abstract

The superjunction (SJ) layer for 600 V is analytically designed for perfect charge balance and compared with SJ MOSFET, where the channel region creates charge imbalance due to unsymmetrical drift layer. We estimated this imbalance created due to the channel region with the help simulation. In order to simulate the SJ MOSFET with physical limitations of the fabrication technology, we have deliberately introduced the imbalance in SJ drift layer by varying the doping density of p pillar and then of n drift layer up to 10% respectively. The effect of this imbalance on the off state and on the on state breakdown voltage of the device investigated in detail with the help of simulation.