Impact of Self-Heating Effect on Plateau Voltage and Gate Charge Measurement for SiC MOSFETs Characterization

Abstract:
The aim of this paper is to analyze the gate charge measurements of SiC MOSFETs and their correlation with junction temperature. The definition of gate-drain charge is related to the Miller region of gate-source voltage that identifies the plateau voltage level, which is very sensitive to junction temperature. According to the working point, self-heating can affect the test by changing the level of plateau voltage and gate-drain charge definition, since junction temperature can change quickly assuming a very different value compared to the device case temperature, which is typically set to 25 °C for this type of measurement. In the present paper the identification of the gate charge is supported by experimental tests varying the gate current and consequently the junction temperature that has also been estimated. Finally, the correlation between plateau voltage and junction temperature is presented and discussed.