Characterization of Threshold Voltage for Application-Oriented Power Cycling Conditions for Wide-Bandgap Power Devices

A quasi-threshold voltage measurement setup is implemented in a test bench to allow online parameter observation during power cycling tests for silicon carbide MOSFETs. The threshold voltage is known to change during operation, either temporarily or non-reversibly, due to degradation and trapping phenomena in the MOS-structure. To evaluate different assembly and interconnection technologies, for conditions as close to the real application as possible, an application-oriented power cycling test setup is examined. The proposed test bench allows the measurement of a quasi-threshold voltage under the influence of different off-state drain-source and gate voltages. Measurements show a decrease of quasi-threshold voltage with increasing off-state drain-source voltage and negative gate-source voltage.