A SiC gate turn-off thyristor with high d i/ d t for fast switching-on applications

Abstract High d i /d t 4H-silicon carbide (SiC) gate turn-off thyristors (GTOs) are investigated and developed for fast switching-on application. This work has focused on accelerating the turn-on process to improve the d i /d t characteristic, and the n -base dopant concentration is carefully designed to increase the injection efficiency of top P + N junction. With reducing n -base dopant concentration from 2.3 × 10 17 cm −3 to 6.8 × 10 16 cm −3 , the injection efficiency is increased about 18%, and consequently the current rise-up process and subsequent lateral propagation of the anode current are obviously accelerated. Experimental results show that the d i /d t capability is greatly improved and a high d i /d t of 126 kA cm −2 μ s −1 is obtained. The excellent d i /d t performance makes the designed 4H-SiC GTO a promising candidate for fast switching-on application.