MA – Investigation of the current pulse shape on bipolar degradation in SiC MOSFETs

Bipolar degradation (BD) in SiC MOSFETs is a reliability issue in automotive inverters generating an increased R_DS,on due to growth of stacking faults. Although the mechanism of BD is well understood the influence of the shape of the stress-current-pulses is yet to be investigated.

This work investigates the influence of different current shapes on bipolar degradation in SiC MOSFETs. Starting point is the waveforms available in the current test setup, which are provided by a commercial power supply respectively a switched inductor. At least two SiC MOSFET manufacturers must be considered, and the sample size must be statistically significant. As a metric to judge BD, accurate measurements of R_DS,on shall be used.

A suitable test plan must be designed and implemented to evaluate the influence of pulse shapes on the BD. The test results must be carefully evaluated with regard to the R_DS,on drift caused by the BD. Furthermore, an analysis of the BD in the semiconductor material must be performed to separate aging of the packaging from the aging of the semiconductor.

Bearbeiter: Hasibul Md Hasan

Betreuer: Rijuta Bagchi, Lukas Farnbacher, Dr. Jürgen Leib

Verantwortlicher:  Prof. Dr.-Ing. Martin März