Failure Analysis and Improvement of the Body Diode in Superjunction Power MOSFET

Abstract

The characteristics of body diode are significant to the reliability of Superjunction power MOSFET (SJ-MOSFET). In the experiments of body diode reverse recovery of SJ - M OSFE T, it is found that there are two kinds of failure mechanisms: overvoltage caused by the snappy reverse recovery and overcurrent caused by the large peak reverse current. Simulations show that the characteristics of body diode can be improved by optimizing the doping concentrations, carrier lifetimes and charge balance of the P/N pillars in the SJ-MOSFET.