Evaluation of 4 mm × 4 mm silicon carbide thyristors

The U. S. Army Research Laboratory (ARL) is evaluating silicon carbide thyristors to determine the extent of silicon carbide capabilities as a possible replacement for silicon in future pulsed switching applications. Individual SiC die measuring 4 mm × 4 mm were pulsed at high temperatures and varying pulse widths. At 150 °C, these thyristors were switched in an RLC circuit up to 3.2 kA and repetitively pulsed at 2.6 kA and 5 Hz for greater than 14,000 pulses. A pulse forming network (PFN) was designed to increase the pulse width and the action seen by the SiC devices. At ambient temperature and a peak current of 2 kA, SiC thyristors were switched in the PFN at a 50% pulse width of 40 us and an action of 150 A²S. These devices were also pulsed at narrower pulse widths in pairs to look at their behavior in parallel. One pair reached a peak total current of 6.7 kA with current sharing as good as 51% / 49%. This paper includes further data on the three aforementioned test procedures, as well as analysis of the devices' failure points.