A novel characterization method for blocking characteristics of high voltage 4H-SiC power devices

SiC power semiconductors typically have large margins in their breakdown voltage to account for epitaxy variation. The proposed method enables the optimization of over-design in the drift region and the performance of the edge termination for high voltage 4H-SiC power devices, such as JBS diodes & MOSFETs. In this study, two designs were evaluated to validate the proposed characterization scheme: Design A - 1200 V, 40 mOhm with conventional floating field rings (FFRs); and Design B - 1200 V, 80 mOhm with ring assisted junction termination extension (RA-JTE). Using this novel method, forward blocking I-V characteristics were measured up to 40 A using short pulsed low energy unclamped inductive switching, which is not possible with only a commercial curve tracer. The measurements demonstrated that Design A with FFRs exhibited a larger “loss” of breakdown voltage compared to Design B with RA-JTE due to leakage generation in the termination region, which was verified by employing high resolution emission microscopy.