High-Voltage 4H-SiC Thyristors With a Graded Etched Junction Termination Extension

For the first time, a graded etched junction termination extension (JTE) is applied to completed 4H-SiC gate turn-off thyristors. These devices demonstrate the feasibility of nonimplanted high-voltage SiC thyristors. The maximal measured forward breakdown voltage of 7.8 kV corresponds very well to the ideal value of 8.1 kV. This letter explains the conceptual procedure to realize an optimal four-step JTE and compares measurement results with those obtained from finite-element simulations.