Unclamped repetitive stress on 1200 V normally-off SiC JFETs

An experimental characterization of new-generation normally-off vertical channel 1200 V SiC JFETs under unclamped repetitive stress (URS) is presented. The drain and gate leakage currents are monitored, and their time evolution is recorded. The degradation of the leakage characteristics has been compared with repeated short circuits tests, at the same stress energy, thus demonstrating that different mechanisms take place in these conditions. Furthermore, a post-failure analysis of the surface of the device by means of a optic microscope indicates that a termination weakness could be the major cause for the device leakage increment and consequent failure.