SiC MOSFET Module Using Body Diode with High Reliability for Industrial Applications

Abstract:
Bipolar degradation is one of the critical issues of SiC MOSFETs when current flows into the body diodes. Although some measures have been taken for this issue, some concerns still remain in practical use. To address the issue of SiC MOSFETs’ body diodes, we performed bipolar current tests on a large number of our 2nd generation planar SiC MOSFETs and investigated their characteristic changes. The results statistically revealed that the probability of VDS(on) shift over 5 % is less than 100 ppm for 600 A rating modules. We also conducted long-term reliability and performance limit tests on some of the degraded MOSFETs caused by bipolar current, showing no significant changes in characteristics under the additional stresses. Based on these promising findings, SiC NX modules optimized for our 2nd generation SiC MOSFETs have been developed. These modules exhibit high performance and reliability for a wide range of industrial applications.