Minienkov O. Phase state and diffusion mobility of the components in nanoscale Ag - Pd, Cu - Ni and Ag - Ge films

Thesis is devoted to the determination of the physical regularities of the characteristic size (film thickness, grain size) effect on the phase state and diffusion mobility of the components in nanoscale Ag - Pd, Cu - Ni and Ag - Ge films. Methods: layered films were formed by means of successive condensation during thermal or electron beam evaporation of the components from independent sources in a vacuum. The morphology and structure of the samples were investigated by transmission and scanning electron microscopy as well as electron diffraction. The kinetics of the solid solution formation in Ag - Pd layered films and the phase state of Ag - Ge films were studied using the change of samples microstructure and lattice parameter during heating directly in the microscope. The activation energy of diffusion and the solid state solubility were determined by the change in the samples electrical resistance during the heating-cooling cycle. Elemental analysis of the films was carried out using the method of X-ray energy dispersive spectroscopy. The kinetics of homogenization of nanosized Ag - Pd film system has been studied. It has been shown that diffusion processes in such object are accelerated and activated at lower temperatures, compared to the bulk ones. It has been shown that the activation energy of grain-boundary diffusion in multilayered Cu - Ni films decreases with decreasing characteristic size of the system. The corresponding diffusion coefficients have been estimated. The eutectic temperature as a function of Ag film thickness has been measured in a wide range of film thicknesses. The significant lowering of eutectic temperature with the film thickness reduction has been registered. The lowest thickness of the Ag film and the temperature required for the liquid phase formation at the metal-semiconductor interface have been found and estimated. The results of the experimental investigation of the solid-state solubility of Ge in thin Ag films have been reported. The significant increase of germanium terminal solubility in silver with characteristic size reduction, as well as the shifting of solubility curves to the region of lower temperatures, has been shown.