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A review of recent advances in the field of epitaxial growth of SiC films on Si by means of a new method of epitaxial substitution of film atoms for substrate atoms has been presented. The basic state

A new method of solid-state epitaxy of silicon carbide (SiC) on silicon (Si) is proposed theoretically and realized experimentally. Films of various polytypes of SiC on Si(111) grow through a chemical reaction (at T = 1100–1400°C) between single-crystal silicon and gaseous carbon oxide CO (at p = 10–300 Pa). Some silicon atoms transform into gaseous silicon oxide SiO and escape from the system, which brings about the formation of vacancies and pores in the silicon near the interface between the silicon and the silicon carbide. These pores provide significant relaxation of the elastic stresses caused by the lattice misfit between Si and SiC. X-ray diffraction, electron diffraction, and electron microscopy studies and luminescence analysis showed that the silicon carbide layers are epitaxial, homogeneous over the thickness, and can contain various polytypes and a mixture of them, depending on the growth conditions. The typical pore size is 1 to 5 μm at film thicknesses of ∼20 to 100 nm. Thermodynamic nucleation theory is generalized to the case where a chemical reaction occurs. Kinetic and thermodynamic theories of this growth mechanism are constructed, and the time dependences of the number of new-phase nuclei, the concentrations of chemical components, and the film thickness are calculated. A model is proposed for relaxation of elastic stresses in a film favored by vacancies and pores in the substrate.

A new method is developed for the solid-phase synthesis of epitaxial layers when the substrate itself is involved into a chemical reaction and the reaction product grows in the interior of substrate layer. It opens up new possibilities for the relaxation of the elastic energy due to attraction of point defects formed during the chemical reaction in anisotropic media. In the same time, the attracting point dilatation centers compose relatively stable formations—dilatation dipoles, named by analogy with electric dipoles, providing significant reduction of the total elastic energy. The correspondent theory of interaction of point dilatation centers in anisotropic crystals is developed. It is eliminated that the most advantageous location of the dipoles is the direction (111) in crystals with cubic symmetry. In order to confirm the theory, the single-crystal silicon carbide films with the thickness up to 200 nm have been grown on silicon (111) substrates owing to the chemical reaction with carbon monoxide. Grown high-quality single-crystal silicon carbide films do not contain misfit dislocations despite the huge lattice mismatch value of $\sim 20\%$ . Also the possibility of growing of thick wide-gap semiconductor films on such templates SiC/Si(111) and, accordingly, its integration into silicon electronics, is demonstrated. In particular, a working LED structure based on gallium nitride has been produced. Finally, the thermodynamic theory of new phase nucleation due to a chemical reaction has been developed and it was shown that in the case under consideration the chemical equilibrium constant generalizes the concentration of adatoms exploited in a one-component nucleation theory.