Manifestation of the Sapphire Crystal Structure in the Surface Nanopattern and Its Application in the Nitride Film Growth

The "quenching" technique was used to investigate the initial stage of the formation of a terracestep nanostructure on the R-cut surface of sapphire crystal upon high-temperature annealing in air. The morphological features of the formation of A- and R-sapphire planes are experimentally shown in dependence on the misorientation direction and qualitatively interpreted with allowance for the surface energy density for the main sapphire faces. The possibilities of forming AlN layers on the R-sapphire surface with a terrace-step nanostructure under thermochemical effect and high-temperature substrate annealing in a mixture of nitrogen and reducing gases are considered.