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The main processes occurring during the migration of molecules of carbon
monoxide CO and silicon monoxide SiO gases through a layer of monocrystalline silicon
carbide SiC of a cubic polytype have been described by the ab initio methods. This problem
arises when a single-crystal SiC layer is grown by the method of coordinated substitution of
atoms due to the chemical reaction of a crystalline silicon substrate with the CO gas. The
reaction products are epitaxial SiC layer and SiO gas. It has been shown that CO and SiO
molecules decompose into separate atoms in the SiC crystal. The Oxygen atoms migrate
through interstices only in the [110] direction (activation energy is 2.6 eV). The Si and C
atoms transit by the vacancy mechanism in the corresponding SiC sublattices with activation
energies of 3.6 eV and 3.9 eV respectively (and also only in the [110] direction).
Keywords: silicon carbide, epitaxy, diffusion, ab initio modelling |
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