Gate-oxide reliability and failure-rate reduction of industrial SiC MOSFETs

We discuss various gate-oxide reliability aspects of silicon carbide (SiC) MOSFETs and highlight similarities and differences of SiC and silicon (Si) technology. Basic concepts of electrical gate-oxide defect screening are introduced and failure probability and the failure-rate after screening is studied based on Weibull statistics. To be able to quantify very low extrinsic failure probabilities (e.g. after electrical screening), we present a new kind of test procedure which we call the "marathon stress test". The results of this test demonstrate that excellent gate-oxide reliability of commercially available SiC trench MOSFETs can be achieved after applying a sufficiently precise electrical screening.