Bogdanov S. Diffusion and structured phase changes in tungsten and silicon by low energetic external interaction

Thesis is devoted to research of diffusion and structure phase changes in tungsten and silicon by low energetic external interaction. In this work the results of experimetal investigations of low energetic treatment influence in plasma glow discharge of Ar on structured changes of powder tungsten and forma-tion of TiSi2(C54) stable silicide phase with low specific resistance is presented. It is established experimentally that at radiation of powder tungsten by Ar ions in low energetic plasma glow discharge, Ar ions are not localized in thin underlayer but they are extended in volume of material from radiated surface in depth. The depth of penetration in mono-, polycrystalline and powder tungsten achieves 5, 7 and 75mkm values at time treatment 72, 72 and 3 h respectively have been deter-mined by radioactive isotopes method. Diffusion coefficient of 85Kr for powder W is 5,5 and 4 times as many as diffusion coefficient for mono- and poly-W. Above mentioned indicate that porosity in tungsten favors by sharp growth of migration velocity Ar and 85Kr by glow discharge condition. Diffusion model of deep penetration of Ar inert gas in powder W is proposed. Advantage formation silicide phases by low energetic thermoion deposition (LETD) method in con-trast to heat treatment is showed. Using LETD method the formation of TiSi2(C54) runs faster ( 55s) than at magnetron sputtering of titanium on monocrystalline Si with subsequent annealing ( 200s). The specific electric resistance for TiSi2(C54) nanosized film at LETD titanium is cm and magnetron sputtering is -24 cm in dependence on annealing ambient. The process investigation of phase formation of TiSi2(C54) nanosized film on monocrystalline Si has allowed to create the model of Si and Ti atoms diffusion in silicide layer by vacancy mechanism. Diffusion Si and Ti atoms runs both grain boundaries and in volume of silicide phase.