Kinetics of the Initial Oxidation of the (0001) 6H-SiC 3 x 3 Reconstructed Surface

Using first-principle calculations, the mechanism of oxygen insertion into the (0001) 6H-silicon carbide 3 x 3 reconstructed surface is investigated. The stable chemisorbed oxygen states, transition states, and activation energies adjoining each oxidation step are identified. Dissociative oxidation occurs barrierlessly at the surface dangling bond, while the lower layers are repulsive toward oxygen. Oxidation of the surface dangling bond will lower the energy barriers for subsequent lower layer oxidation, after which lower layer oxidation is possible.