A SiC gate turn-off thyristor with high di/dt for fast switching-on applications

Abstract

High di/dt 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 di/dt 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 × 1017cm−3 to 6.8 × 1016cm−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 di/dt capability is greatly improved and a high di/dt of 126 kA cm−2 μs−1 is obtained. The excellent di/dt performance makes the designed 4H-SiC GTO a promising candidate for fast switching-on application.