Rusavsky A. Structural, optical and mechanical properties of films of a-Si1-xCx(:H) deposited by the method of magnetron sputtering.

This dissertation deals with the decision of the scientific task on the study of processes of forming of the amorphous silicon-carbon films obtained by the magnetron sputtering technique, influence of physical and technological conditions of synthesis and subsequent heat treatments on the structure of near-order, optical and mechanical properties of material for revealing the key mechanisms, which determine these properties. The original method of deposition of a-SiC(:H) thin-films is suggested and developed - the method of RF- magnetron sputtering of crystalline silicon carbide target with an area, limited only by the size of the magnetron cathode. The target is a large-grainy batch of silicon carbide (6Н) crystals of 1-3 mm size. The influence of the gas mixture composition during deposition is studied on the density and magnitude of mechanical stress in tapes of a-SiC and a-SiC:H. On the basis of these results the conception is suggested to control the mechanical stress in silicon-carbon films by variation of physical and technological parameters of deposition. By means of paramagnetic resonance, IR and Raman spectroscopy the passivation of the defect states in a-SiC:H films and formation of new silicon-carbon states are investigated. Such a structural reconstruction substantially increases the PL efficiency. The effect of the low temperature thermal annealing (4500C) in an inert and oxidizing environment (water vapor, oxygen) is studied on the structural reconstruction and luminescent properties of a-Si(1-x)C(x):H films with stoichiometrical composition (x=0.5) and with an excess of carbon (x=0.7). It is found that the basic effect of the low temperature heat treatment of а-SiC:H thin-films in an oxidizing environment is the enhancement of white spectrum photoluminescence. The strongest effects of oxidization, and also intense photoluminescence of white light, were observed in the carbon-rich а-SiC:H films, that is explained by higher porosity, and also is related to the presence of carbon precipitates. The method of synthesis of light-emitting films is suggested using low temperature oxidation in the atmosphere of oxygen of the carbon-rich a-Si(1-x)C(x):Tb:H films deposited by the method of reactive magnetron sputtering. It is found that activation of photoluminescence of ions of terbium of Tb3+ in such material can occur at the temperature of oxidation 500?6000С. The oxidation resistance of a-SiC:H and a-SiC films is analysed. It is found that the increase of the carbon content in films reduces their density and oxidation resistance, especially in the oxygen environment. The difference in the mechanisms of oxidation of a-SiC:H and a-SiC films by the water vapor and dry oxygen is demonstrated. If oxidation by the water vapor of a-SiC tapes is accompanied by precipitation of free carbon in the bulk of the film, then, in the case of oxidation of a-SiC:H films by dry oxygen, carbon that is released after the break of Si-C bonds, oxidizes and retires from the material in the form of volatile oxides.