Theoretical and Experimental Study of 22 kV SiC Emitter Turn-OFF (ETO) Thyristor

Controllable three terminal high voltage (>10 kV) power switches based on silicon carbide (SiC) material are gaining significant attentions since silicon (Si) power switches such as insulated gate bipolar transistors (IGBTs) are typically designed for much lower blocking voltages. After more than 30 years of commercial development, there is a fundamental limitation in designing Si IGBTs with more than 6.5 kV voltage rating. On the other hand, the voltage barrier for SiC power devices could easily exceed 10 kV. In this paper, a world record 22 kV SiC p-type emitter turn-OFF (ETO) (p-ETO) thyristor is reported and analyzed as a promising candidate for high-voltage applications, such as solid-state circuit breaker, HVdc, flexible alternating current transmission system (FACTS), and motor drives. The device is based on a 2 cm² 22 kV p-type SiC gate turn-OFF thyristor (p-GTO) structure. Its static performances are analyzed exhibiting a high voltage (22 kV) blocking characteristic, ultralow leakage current, and a low forward voltage drop (~7 V at 100 A) for a broad range of temperatures. The dynamic performances including turn-ON and turn-OFF are studied. Key switching characteristics such as turn-OFF storage time, turn-OFF loss, dv/dt, and di/dt are presented and analyzed. In addition, the large reverse biased safe operation area (RBSOA) of the 22 kV SiC ETO is theoretically analyzed and verified by simulations and experimental tests.