OXIDATION OF SINGLE-CRYSTAL SILICON-CARBIDE .1. EXPERIMENTAL STUDIES

The oxidation of single crystal SiC in dry oxygen (10−3-1 atm and 1200°–1500°C) followed parabolic kinetics. Two different apparent activation energies were calculated for oxidation of the (0001) C faces of SiC, approximately 120 kJ/mol below 1350°C and 260 kJ/mol above 1350°C. Two regimes were not apparent for oxidation of the (0001) Si faces, and apparent activation energies lay between 223 and 298 kJ/mol. Double oxidation experiments using 16O2 and 18O2 indicated that the process is dominated by the transport of molecular oxygen at lower temperatures (<1300°C) with a substantial contribution from diffusion of ionic oxygen at higher temperatures. Epitaxially grown Si 13C films on alpha-Si 12C substrates via CVD were used to study carbon transport behavior during oxidation of SiC. Depth profiles for carbonaceous species using SIMS showed that carbon can transport quickly through the oxide layer, which eliminates the possibility that transport of carbonaceous species is rate controlling in the oxidation of SiC. Oxidation mechanisms of SiC are discussed on the basis of these results. © 1990, The Electrochemical Society, Inc. All rights reserved.