SiC Power MOSFETs – Status, Trends and Challenges

Abstract

SiC power MOSFETs are attractive electronic power switches for innovative power supply and motor drive solutions. The paper discusses this statement and specifies market segments offering the best chances for a commercialization. Due to well-known difficulties in achieving adequate channel conductivity, a lot of SiC-MOSFET publications focus on the channel mobility. However, for a power MOSFET this is only one important parameter affecting the performance. Other characteristics have to be considered too for an honest evaluation: transfer characteristics and blocking capability over the standard operation temperature range, handling of gate oxide stress and related reliability issues, capability of paralleling, dynamic stability, body diode characteristics, reproducibility of the fabrication process and device size. Various attempts have been made in recent years in order to address these features. Approaches differ in the use of different crystal orientations and polytypes, accumulation or inversion channel, implanted or epitaxially grown channels and novel oxidation techniques. Worldwide a trend to the planar DIMOS concept can be observed. Our present results are shown for a power SiC MOSFET designed for 10 A / 1200 V. Key data are a specific on-resistance of 12 m1cm2, the desired low but positive increase of the onresistance with temperature, static avalanche (20 mA DC @1574 V), short-circuit stability at 600 V for 20 9s and robust switching behavior.