Study on Gate Bias Voltage Application Conditions to Prevent the Knee Voltage Shift of the SiC–MOSFET Body Diode Depending on Gate Bias Voltage during Transient Temperature Measurements

Abstract

This paper reports a method for determining the gate bias voltage condition during transient temperature measurement using a SiC–MOSFET body diode. The Vg–Vsd characteristic of the device was investigated. There exists a plateau where Vsd does not change with changes in Vg. In this plateau, transient temperature measurement using a body diode is possible under the gate bias condition. This method was applied to three devices with different characteristics. The results confirmed that transient temperature measurement is possible by selecting appropriate Vg values according to the relevant device characteristics. The transient temperature of each module in which three devices (Device A, Device B1, and Device B2) are mounted in the same structure package are measured. The three transient temperature graphs agree well, and the three structure function graphs are also in good agreement. Thus, the proposed method allows the rapid determination of parameters of a transient thermal analysis for an unknown device.