Analysis and optimization of the switching noise for Super-junction MOSFET in full bridge converter system

In this paper, the switching noise of Super-junction MOSFET in full bridge converter system has been investigated. According to the experimental results, the largest noise is induced by the steep reverse recovery current variation (di(rr)/dt) during the Super-junction MOSFET body diode reverse recovery. In order to understand the phenomena, the TCAD simulations and analyses have been carried out. It is found that the reverse recovery currents in the cell region and the termination region combine to result in the steep di(rr)/dt. The current in cell region aggravates the current variation, however, the current in termination region contributes to alleviate the current variation. Furthermore, it is also shown that increasing the hole injection level in termination region can alleviate the di(rr)/dt, and then the switching noise is reduced effectively. Finally, an optimized structure with heavily doped main junction in the termination region is proposed for the SJ-MOSFET, which can increase the hole injection efficiency greatly to reduce the switching noise during the Super-junction MOSFET body diode reverse recovery.