Power Cycling of SiC-MOSFET Single-Chip Modules with Additional Measurement Cycles for Life End Determination

To meet the trend of the increasing market of SiC-based power electronics, ECPE is under refinement of the AQG324, to adapt reliability and lifetime testing of power modules with Power Cycling Testing (PCT) also for SiC-based power modules. Based on this qualification guideline the end of life (EoL) criteria of the forward voltage drop VDS is discussed with power cycling (PC) results of SiC-MOSFET single-chip modules and it is shown that different lifetime results can be obtained, if VDS is measured accordingly to different measurement and thermal conditions of VDS. Therefore, PC with a main cycle and additional measurement cycles is introduced to measure VDS and the thermal resistance Rth independently from PC and with simple measurement equipment. Using this procedure, three SiC-MOSFET single chip vehicles with different top-side contacts in fact Al-wire, Al-ribbon and AlCu ribbon bonds are compared using a ‘scientific PC’ and measurement cycles to retain EoL criteria.