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

Abstract

AbstractThe marked lack of long‐term 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 medium charge‐to‐failure value of more than 400C/cm2 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 room temperature. An ONO gate dielectric DMOS was demonstrated to show stable normally‐off transistor operation on 4H‐SiC. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 90(5): 1– 10, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20329