Papers by Author: Sergey I. Sidorenko

Abstract: Processes involved in the structure and phase formation in the thin film systems Sn(4 nm)/Cu(14 nm) and Сu(14 nm)/Sn(8 nm) in the temperature range 130-500 оС were studied using “in situ” electron imaging and Transmission Electron Microscopy methods (TEM). Solubility of Sn α – solid solution Cu-Sn has been determined from the changes in the lattice parameter. This work was performed in the framework of the Swedish Institute supported cooperative research project “Thin metal films – the interplay of structure diffusion and boundaries” (SI dnr 00699/2009).

Abstract: The surface diffusion layers formed in preliminary deformed (350 %) -Fe after nitriding at 853 K in ammonia medium were studied by means of metallography, electron microscopy, microhardness test and X-ray powder diffractometry. The preliminary plastic deformation (PPD) effects non-monotonously on the structure, microhardness and thickness of nitride - and -phases layers formed in -Fe. The narrow intervals of deformations of 3-8 % and 20-30 % were found in which the accelerated formation of nitride - and -phases occurs.

Abstract: Thermally stimulated solid state reactions in the Ni(10 nm)/Si(001) film system that occur under the annealing in the nitrogen ambient were researched by methods of сross-sectional transmission electron microscopy and scanning electron microscope. It was established that NiSi2 formation consists of several steps: a formation of the NiSi polycrystalline silicide thickness of which twice higher initial thickness of Ni layer; prevailed diffusion of Ni atoms out of NiSi into Si substrate according with lattice mechanism and appearing of exceeding vacancies at grain boundaries; a formation of epitaxial NiSi2 nuclei at separate spots of NiSi/Si(001) interface; regular growth of NiSi2 phase inclusions at the expense of NiSi layer “diffusion dissolution”; a formation of NiSi2 spherical inclusions in the lattice of Si matrix and their coalescence.

Abstract: By the method of radio isotopes (method of depleting) the redistribution of 63Ni was investigated in the surface layer of iron after the Electric-spark alloying by titanium and zirconium in a carbon containing atmosphere and in air. It is proved that the Electric-spark alloying results in diffusive penetration of 63Ni both in the alloyed layer and in material of basis. The depth of isotope’s penetration depends on the nature of an anode material. Alloying by titanium results in penetration of nickel on the depth of 10 μm, that is almost 2 times more than the depth of its penetration if a zirconium anode is used. In particular, a microhardness, microstructure and phase composition of alloyed layers are examined. It is assumed that alloying of iron by zirconium results in the hardness increase. The alloyed layer equals to 10 GPa (at treatment in kerosene) and to 8,6 GPa (at treatment in propane-butane) that exceeds the microhardness values at alloying by titanium.

Abstract: The laser-induced mass transfer in thin-film substrate /Cr/Cu/Ni system is studied by means of Auger Electron Spectroscopy (AES). For the laser-pulse energy values, E = 100-170mJ, the diffusion of Cu atoms into Ni layer and their accumulation within this layer are observed, whereas at E > 170mJ the same is true for Cr atoms. The observed phenomena are explained on the basis of calculated temperature distribution in the system at issue during lased action. Enhanced transfer of Cr atoms towards external surface is observed under the irradiation regimes leading to the melting of intermediate copper layer. Diffusion coefficients of copper and chromium calculated from their surface accumulation show an exponential dependence on the laser-pulse energy. Under laser heating, the diffusion processes are more manifested as compared with those under conventional thermal annealing. This is bound up with higher concentration of nonequilibrium defects generated within the irradiation zone.

Abstract: The method of Ionization Spectroscopy is used to study the thermo-induced kinetics of surface segregation of the Pt80Co20(111) alloy components. The temperature dependence of the Co diffusion coefficient in this alloy is determined. It is found that the value of the activation energy for the segregation of Co atoms in the near-surface region is close to the heat of sublimation of pure Co.

Abstract: Influence of an annealing environment and film thickness on the phase formation in the Ti(30 nm)/Si(100), [(Ti+Si) 200 nm]/Si(100) thin film systems produced by magnetron sputtering and the Ti(200 nm)/Si(100) thin film system produced by electron-beam sputtering were investigated by X-ray and electron diffraction, Auger electron spectroscopy (AES), secondary ion mass-spectrometry (SIMS) and resistivity measurements. Solid-state reactions in the thin film systems under investigation were caused by diffusion processes during annealing in the different gas environments: under vacuum of 10-4 - 10-7 Pa, flow of nitrogen and hydrogen. It is shown that the decrease of Ti layer thickness from 200 to 30 nm in the Ti/Si(100) film system causes the increase of the transition temperature of the metastable C49 TiSi2 phase to the stable C54 TiSi2 phase up to 1070 K at vacuum annealing. During annealing in the nitrogen flow of the Ti(30 nm)/Si(100) thin film system the C49 TiSi2 is the first crystal phase which is formed at 870 K. For annealings of the [(Ti+Si) 200 nm]/Si(100) thin film system by impulse heating method or for furnace annealings in inert gas atmosphere of N2, Ar, H or higher vacuum (10-5 Pa) the crystallization process has two stages: the first metastable C49 TiSi2 phase is formed at 870 K and then at higher temperatures it is transformed to the stable C54 TiSi2 phase.

Abstract: Low-temperature diffusion in thin films of the stable isotopes, 56Fe/57Fe, was studied by applying secondary ion mass spectrometry (SIMS). Processing of the concentration profiles obtained was done by using the Hall – Morabitto “median gradient” method. The bulk and intergrain selfdiffusion coefficients were determined.

Abstract: Phase transformations during the heating of amorphous Fe-Si-B alloys were investigated. The differential thermomagnetic analysis and X-ray method are used for the studies. The intervals of phase transformations are revealed, and the magnetic properties of phases are determined. The method of calculation of magnetic effects during the phase transformations, registered by differential technique is suggested.