Silicon Carbide Emitter Turn-off Thyristor, A Promising Technology For High Voltage and High Frequency Applications

A novel MOS-controlled SiC thyristor device, the SiC emitter turn-off thyristor (ETO), as a promising technology for future high voltage high frequency switching applications has been developed. The world´s first 4.5-kV SiC p type ETO prototype based on a 0.36 cm² SiC p type GTO shows a forward voltage drop of 4.6 V at a current density of 25 A/cm² and a turn-off energy loss of 9.88 mJ. The low loss indicates that the SiC ETO could operate at a 4 kHz frequency with a conventional thermal management system. This frequency capability is about 4 times higher than the 4.5-kV-class silicon power devices. The numerical simulations have been carried out to discuss the potential improvement of the high voltage (10-kV) SiC ETOs. The results show that the 10-kV SiC n type ETO has much better trade-off performance than that of the p type ETO due to a smaller current gain of the internal lower (PNP) bipolar transistor in the SiC n type GTO. The experimental and theoretical studies show that the SiC ETO is a promising candidate for high-voltage (>5-kV) high-frequency power conversion applications.