10-kV 4H-SiC Gate Turn-OFF Thyristors With Space-Modulated Buffer Trench Three-Step JTE

Ultrahigh-voltage 4H-silicon carbide (SiC) gate turn-OFF thyristors (GTOs), with multiple space-modulated buffer trench (SMBT) regions on the traditional three-step junction termination extension (3S-JTE), have been investigated and fabricated. With the adoption of these SMBT regions, the electric field crowding near the edges is effectively suppressed and the sensitivity of edge maximum electric field on the etching depths is greatly reduced. The fabricated SiC GTOs with an improved 3S-JTE can accomplish a high blocking capability of 10 kV, which improves the breakdown voltage by 4 kV compared with the traditional 3S-JTE.