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.
ASJC Scopus subject areas
- 化学 (全般)