Dynamic Calibration of Junction Temeperature of SiC MOSFETs for Power Cycling

Temperature dependent, transient effects were observed during calibration of virtual junction temperature of SiC trench MOSFETs within power cycling tests. Depending on the device design resp. semiconductor manufacturing these effects may lead to a significantly wrong junction temperature measurement thus leading to a wrong interpretation of results in lifetime testing, e.g. acc, to AQG324 PCmin, PCsec. This study investigates the time-dependent transient response of the body diode's forward voltage under test conditions with a switched gate bias applied. Based on the results, a new approach of the measurement of T<inf>vj</inf> is proposed. This dynamic calibration method is applied to address the transient effects detected during PCT. This method is applied to SiC MOSFETs of different manufacturers. A parameter study is carried out to determine the effect of test parameters on the transient response.