6500V-100A SiC JFET-Based Half-Bridge Module

Over the last decade, tremendous efforts have been invested in developing high voltage SiC power switches. At present, SiC unipolar power switches including MOSFETs and normally-on JFETs have been commercially available at voltage ratings up to 1700V. However, medium voltage (>3300V) SiC power devices are still not commercially available mainly because of the very high cost of high quality medium-voltage SiC epi-wafers. There is a strong need for a cost-effective medium-voltage SiC power switch that can be commercialized and moved into mass production quickly. In this program, United Silicon Carbide, Inc. (USCi) proposes to develop such a 6.5kV SiC power module based on the technology of series-connecting multiple commercial available low-voltage (1,200V to 1,700V) SiC normally-on JFETs. The proposed approach has substantial performance advantages over the medium-voltage SiC MOSFET solution. For example, the proposed approach has a higher threshold voltage (>3V at 150C) providing higher noise immunity, can be driven by a conventional gate driver for ease to use, and has an excellent built-in antiparallel diode with a knee voltage of only 0.7V.