ISPSD2021 | The 33rd International Symposium on Power Semiconductor Devices and ICs (ISPSD)

Short Course Program

Power MOSFETs and IGBTs in 4H-SiC

Sei-Hyung Ryu, Senior Research Scientist, Wolfspeed, a Cree company, USA

Sei-Hyung Ryu (SM’89–M’98-SM’03) was born in Seoul, Korea in 1969. He received B.S. degree in Electronics Engineering in February 1992 from Seoul National University (Seoul, Korea), and M.S. and Ph.D. degrees in Electrical and Computer Engineering in December 1993 and in May 1997, respectively, from Purdue University (West Lafayette, IN), where he developed the first P-well CMOS technology in 6H-SiC for smart power applications.

He continued his research in as a Post-Doctoral Research Associate with the Wide Bandgap Research Group of Purdue University until January 1999. In February 1999, he joined Cree, Inc., where he has been developing high performance power devices in 4H-SiC. Sei-Hyung Ryu played a key role in commercial development of 4H-SiC power Schottky diodes, and is currently focused on the development of MOS based power switches in 4H-SiC, which include 4H-SiC power MOSFETs and 4H-SiC IGBTs. His research interest includes high power, high temperature power devices, devices for harsh environments, and novel devices in wide bandgap semiconductor materials. He authored two book chapters and more than 85 technical presentations and publications.

Sei-Hyung Ryu was a recipient of the Best Paper Award in the 13th International Symposium of Power Semiconductor Devices and Integrated Circuits (ISPSD) in 2001. He is a Senior Member of IEEE.


Silicon Carbide is an indirect bandgap compound semiconductor that can be thermally oxidized to form stable oxide (SiO2) layers. Many of the PN junction and MOS based power devices structures available in Silicon, such as Power MOSFETs, BJTs, and IGBTs, can be fabricated in Silicon Carbide and have been experimentally demonstrated. High performance, low loss Silicon Carbide power MOSFETs were reported with blocking voltages ranging from 600V to 15 kV. Silicon Carbide bipolar devices, such as IGBTs and GTO Thyristors, designed for significantly higher voltage applications, also showed superior on-state and switching performance over Silicon devices.

It should also be noted that Silicon Carbide is a wide bandgap semiconductor that have vastly different electrical, physical, and chemical properties from those of Silicon. Although the operating principles of the devices are the same for Silicon and Silicon Carbide MOSFETs and IGBTs, Silicon Carbide devices require very different optimization approaches due to the differences in materials properties.

This course will start with a brief discussion on differences in material properties between Silicon and Silicon Carbide, then a discussion on design trade-offs and optimization approaches for Silicon Carbide MOSFETs will be provided. Device ruggedness evaluation methods will also be discussed.