On-state characteristics of SiC thyristors for the 8–20 kV regime

Silicon carbide is attractive for high-voltage power switching applications because its critical field is 8-10x higher than silicon. In SiC MOSFETs, the drift region resistance increases as the square of the blocking voltage, and for sufficiently high voltages (>10 kV) this resistance becomes a major limitation. Bipolar devices (BJTs, IGBTs, and thyristors) inject minority carriers into the drift region, resulting in conductivity modulation that dramatically reduces this resistance. BJTs and IGBTs are single-injection devices, but thyristors inject carriers into the drift region from both sides, resulting in increased conductivity modulation. Hence, thyristors are attractive for high-voltage, low-frequency applications such as electric power utility distribution.