Ultra-high voltage 4H-SiC gate turn-off thyristor for low switching time**Project supported by the National Natural Science Foundation of China (Grant No. 51677149).

Abstract

An ultra-high voltage 4H-silicon carbide (SiC) gate turn-off (GTO) thyristor for low switching time is proposed and analyzed by numerical simulation. It features a double epitaxial p-base in which an extra electrical field is induced to enhance the transportation of the electrons in the thin p-base and reduce recombination. As a result, the turn-on characteristics are improved. What is more, to obtain a low turn-off loss, an alternating p+/n+ region formed in the backside acts as the anode in the GTO thyristor. Consequently, another path formed by the reverse-biased n+–p junction accelerates the fast removal of excess electrons during turn-off. This work demonstrates that the turn-on time and turn-off time of the new structure are reduced to 37 ns and 783.1 ns, respectively, under a bus voltage of 8000 V and load current of 100 A/cm2.