Enhancing gate turn-off thyristor blocking characteristics by low temperature defect passivation technology

In the past, gate turn-off (GTO) thyristors were commonly used to either increase the length of the drift region or reduce the doping concentration to increase high-voltage and high-power applications. However, this results in an on-resistance (R _on) increase. In this study, we applied a supercritical fluid (SCF) treatment to devices which has the advantage of high permeability and low-temperature processing to passivate SiC-GTO bulk defects. After the proposed defect passivation, the breakdown voltage has been improved by 8% without increasing on-state resistance. In addition, the leakage current has also been suppressed more than 30% in average. This study also uses electrical analysis to understand the characteristics of the devices after SCF treatment, and then discusses the passivation mechanism of materials of the devices from this treatment. (paper)