Power Cycling Test Using Positive and Negative Gate-Voltage Switching Circuit for SiC-MOSFET Power Module

The power cycling (PC) test is one of the important methods to assess the reliability performance of power modules under the actual switching operation of power semiconductor devices. The actual operation of silicon carbide metal-oxide-semiconductor field-effect transistors (SiC-MOSFETs) require positive and negative gate-voltage switching. This study investigated the effects of positive and negative gate-voltage switching on the characteristics of SiC-MOSFETs during PC tests. Two types of test circuits were used: a traditional circuit with a fixed positive gate-voltage and a new circuit with positive and negative gate-voltage switching. The traditional test circuit led to degradation in SiC-MOSFETs, including gate threshold-voltage shifts and on-state voltage fluctuations. The degradation of SiC-MOSFETs was improved by applying a positive and negative gate-voltage switching every cycle during the PC test. The new test circuit led to the accuracy improvement of PC lifetime estimations. The results demonstrated that the positive and negative gate-voltage switching were essential for the PC tests of the SiC-MOSFET power module.