Semenov A. Physical and technological basis of the obtaining and modification of nanocrystalline silicon carbide films

The thesis is devoted to the development of physical and technological basis for the obtaining and modification of nanocrystalline SiC films under the conditions of direct deposition of carbon and silicon ions with elevated energy.There was proposed the method of low-temperature formation of nanocrystalline SiC layers on the substrate based on direct deposition of carbon and silicon ions with elevated energy. For realization of this method, a vacuum-arc source of carbon and silicon ions with polycrystalline SiC cathode, was developed. For the first time, the mechanism of the influence of the ion energy and the substrate temperature on the structure of SiC condensate was established, and the temperatures of the formation of nanocrystalline SiC films of non-cubic polytypes 15R-SiC, 21R-SiC, 24R-SiC, 27R-SiC, 51R-SiC, 6H-SiC were experimentally determined. Proposed was the model of thermal balance on the substrate during the formation of SiC films under the conditions of direct deposition of carbon and silicon ions with an energy of ~100 eV. For the first time, nanocrystalline SiC films were shown to possess anomalously high third-order nonlinear optical response, the maximum value of the nonlinear susceptibility х3 (~ 10-5 esu) being characteristic of the films of 21R-SiC polytype with a nanocrystal size of ~10 nm. The gradient method of the formation of heterostructures based on nanocrystalline SiC layers in the single cycle of direct ion deposition, was developed. For the formation of the nanocrystal/boundary region interface and charge compensation in the boundary regions there was used annealing in О2 atmosphere.Developed is a series of thermal sensors based on nc-SiC films working under complex conditions which possess elevated reliability and prolonged service life.High-resistance protective coatings are developed for powerful HF pin diodes, photo-converters, including those for solar and optical elements, which provide stable operation of the devices under complex climatic conditions. Developed are thermally stable protective coatings for welding torch elements which provide the increase of weld quality and duration of continuous torch work up to 30%.