SIMS study of SiC single crystal oxidized in atmosphere containing isotopic water vapor

Abstract

Double oxidation of SiC single crystal was carried out in oxidizing gas (O2 or H2O) at 1673 K first and then in isotopic water (H218O or D2O) at 1473 K or 1573 K to trace diffusing species during oxidation at high temperatures. SIMS analysis revealed that deuterium was enriched near SiO2/SiC interface when SiC was oxidized in Ar/D2O gas mixture at the second oxidation step, indicating that water molecules or hydroxyls diffused in SiO2 layer to the SiO2/SiC interface. Large amount of carbon in SiO2 scale near the SiO2/SiC interface after oxidation in dry Ar/O 2 gas mixture suggests a possibility that outward diffusion of carbonaceous species can be rate-controlling step during oxidation in dry Ar/O2 atmosphere. Decrease in the amount of the carbon with oxidation time in Ar/H218O gas mixture at the second oxidation step implies that the outward diffusion of carbon-aceous species in SiO2 scale was promoted during oxidation in atmosphere containing water vapor. © 2008 The Ceramic Society of Japan. All rights reserved.