Fundamentals of SiC Power Devices – Performance and Reliability

SiC power devices significantly outperform the well-established Si devices in terms of high breakdown voltage, low power loss, and fast switching. In the first part, the major features and current status of SiC power devices are briefly introduced. After this introduction, the “SiC unipolar limit” is updated by using the accurate impact ionization coefficients and electron mobility along the c-axis, both of which were recently determined. Next, recent progress in SiC power MOSFETs, which are the most important unipolar devices, is described with an emphasis on the improvement of channel mobility at the SiO₂/SiC interface. The development of SiC bipolar devices such as pin diodes and IGBTs, which are promising for ultrahigh-voltage (> 10 kV) applications, is presented, where the effect of carrier lifetime enhancement and its limitation are discussed. In addition, major reliability issues of SiC power devices such as bipolar degradation (stacking fault expansion), threshold voltage instability, and short-circuit ruggedness are described together with their improvement. In the final part, important remaining issues in SiC material and device technology are shown.