Possibility of the use of intermediate carbidsiliconoxide nanolayers on polydiamond substrates for gallium nitride layers epitaxy

The results of using carbidsiliconoxide ($a$-C : SiO$_{1.5}$) films with a thickness of 30–60 nm, produced by the pyrolysis annealing of oligomethylsilseskvioksana (СН$_{3}$–SiO$_{1.5}$)$_{n}$ with cyclolinear (staircased) molecular structure, as intermediate films in the hydride vapor phase epitaxy of gallium nitride on polycrystalline CVD-diamond substrates are presented. In the pyrolysis annealing of (СН$_{3}$–SiO$_{1.5}$)$_{n}$ films in an atmosphere of nitrogen at a temperature of 1060$^\circ$C, methyl radicals are carbonized to yield carbon atoms chemically bound to silicon. In turn, these atoms form a SiC monolayer on the surface of $a$-C : SiO$_{1.5}$ films via covalent bonding with silicon. It is shown that GaN islands grow on such an intermediate layer on CVD-polydiamond substrates in the process of hydride vapor phase epitaxy in a vertical reactor from the GaCl–NH$_{3}$–N$_{2}$ gas mixture.