Improved Clamping Capability of Parasitic Body Diode Utilizing New Equivalent Circuit Model of SBD-embedded SiC MOSFET

摘要

In the SBD-embedded SiC MOSFET, the operation of the parasitic PN diode that causes degradation of forward voltage of the diode is suppressed by the incorporated SBD. The aim of this study is to improve the maximum current at which the parasitic PN diode does not operate (Iumax). We confirmed the limitation of the existing equivalent circuit model used as a guideline to improve Iumax, and then developed a new circuit model. In addition, a new guideline to improve Iumax has been derived based on the equivalent circuit model. Utilizing this guideline, we have tried to improve Iumax of 3.3 kV SBD-embedded SiC MOSFET experimentally. Iumax at 200°C has been improved to 4.72 times that of the conventional device. Though it has been known that Iumax decreases with temperature, this significant improvement in Iumax is a promising result for future application of SBD-embedded SiC MOSFET above 175°C.