Gate Oxide Long-Term Reliability of 4H-SiC MOS Devices

Reliability of the gate oxide on SiC is a pressing concern for deploying SiC MOS-based devices in real systems. While good projected oxide reliability was obtained recently under highly accelerated test conditions, indication that such projection may not be valid at lower operating fields was also reported. In this work, results from long-term TDDB stress (over 7 months) at 6 MV/cm and 300 degrees C on 4H-SiC MOS capacitors is reported. We confirm that lifetime projection from high-field data continues to be valid and no change in field acceleration factor is observed. The discrepancy between our results and the early prediction of poor reliability is examined.