Highly reliable SiO2/SiN/SiO2(ONO) gate dielectric on 4H-SiC

The marked lack of long-tcrm reliability in thermal gate oxides has thwarted practical applications of siC power MOS devices. Gate dielectrics with a SiO2/SiN/SiO2 (ONO) structure have been studied and optimized on a commercial 4H-SiC epitaxial substrate as a fundamental resolution to this problem. A medim charge-to-failure value of more than 400 C/cm (2) was achieved for polycrystalline gate MONOS capacitors with an equivalent SiO2 thickness of 40 nm and fabricated with a typical power MOS process. The medium time-to-failure at an operating field of 3 MV/cm was extrapolated to be over 2 million years at roorn temperature. An ONO gate dielectric DMOS was demonstrated to show stable normally-off transistor operation on 4H-SiC. (C) 2007 Wiley Periodicals, Inc.