V. E. Yurasova

Formation of cones during sputtering

Abstract Conditions of cone formation on the sputtered surface of single crystals : re examined. The effects of the various irradiation factors (dose, face orientation, ion beam incidence angle, etc.) on cone formation are studied. The cone formation on sputtered surfaces is primarily explained by crystal growth under the conditions of atom migration and target sputtering.

The effect of nitrogen content on the structure and mechanical properties of TiN films produced by magnetron sputtering

Abstract Titanium nitride TiN χ layers with different nitrogen content have been deposited on hard tool steel substrates by unbalanced magnetron sputtering at different nitrogen partial pressures so that the effect of nitrogen content on the structural and mechanical properties of the films could be studied. The film microhardness was found to have a maximum at χ ≈ 0.9. For this value of χ a maximum content of carbon and the highest lattice distortion (especially for the (200) plane) was observed. Chemical bonding between the film components was shown to be the determining factor for the microhardness, as well as intrinsic stress created due to lattice imperfections.

Emission of secondary particles during ion bombardment of metals in the phase transition region—Part 1. Sputtering

Abstract A review of recent studies of the emission of secondary particles (neutral atoms, ions and photons) under ion bombardment of metals in the phase transition region of the first and second type is given. A discussion of the observed anomalies in emission is presented and theoretical models allowing explanation of experimental data are considered. In the present first part of the review results on sputtering are given.

Secondary particle emission from metals under ion bombardment in the region of phase transitions—Part 2. Charged-particle and photon emission

Abstract This part of the review deals with the ion induced secondary ion, electron, and photon emissions and with ion scattering during phase transitions of the first and second kinds. New experimental and theoretical results bearing on ferromagnetic sputtering near the Curie point are also presented.

Experimental and computer study of ion scattering from single crystals

Abstract The spatial distribution of reflected particles was experimentally studied in the case of oblique incidence of 4.5 keV Ar ions on a (001) Cu face along the (110) and (100) planes. The distribution in ejection angles of the reflected particles was found to have several peaks and minima. To explain the results of these reflection experiments a computer study was performed. The shape of the calculated spatial distribution curves appears to be very sensitive to variations of the constants in the interaction potentials. Some features of the spatial distribution of the reflected ions have been shown to be connected to the motion of ions in surface semichannels. The spatial distribution of the neutral component of scattered and sputtered particles was also studied in the experiments. A predominant yield of the sputtered particles was observed not only in the low-index but also in high-index directions.

Computer calculations of single crystal sputtering by low energy ions

Abstract A study of copper crystal sputtering by 10–2500 eV Ar ions was performed by molecular dynamic computer simulation. Good agreement with experiment was obtained in spatial and energy distributions of sputtered atoms and in energy dependence of sputtering. A sharp peak was observed in energy spectra of atoms moving in the uppermost (001)Cu layer, appearing due to correlated collisions for ion energies E0≤50 eV. The nonmonotonic dependence of average and maximal energy transferred by ions to atoms in (001) layers on the layer number was established. It was found that there is an optimum energy of the incoming ions which gives to the greatest number of atoms in upper layers with energy higher than some chosen threshold.

Computer simulation of ion scattering by polycrystals

Abstract The models of random media used at present in describing polycrystal scatteringcannot explain some experimental facts, such as the double-scattering peak in the energy spectra of reflected ions. Two models of simulation of ion interactions with polycrystals are proposed here, namely 1) the model of random filling of the coordinative spheres in which the polycrystal is represented by a set of singlecrystal coordinative spheres with arbitrary positions of atoms and the distances between atom may sometimes be smaller than those in single crystal, a fact that can be treated as the presence of an imbedded atom; 2) the model of arbitrary selection of the bombarded face in which the surface and incidence planes are selected randomly for each ion (or of a group of ions). In both models, the atoms are free, the Born-Mayer potential is used, and thermal vibrations of atom are included. A good agreement with experimental results has been obtained in both methods.

Spatial and energy distributions of secondary ions produced by ion bombardment of single crystals

Abstract Angular distribution of the 115In+ ions sputtered from the (111) and (1 1 1) polar faces of InSb single crystal has been experimentally studied. Angular and energy distributions of the 63Cu+ ions sputtered from the (100) Cu single crystal face were also studied. In the latter studies the use was made of a method permitting the energy distribution curve to be obtained in case of continuous cyclic passage through the various azymuthal angles of ion ejection. Such curve displays oscillations due to angular anisotropy of secondary ion emission and permits energy distributions to be obtained for all azymuthal angles of sccondary ion ejection (at given polar angles). The sputtering was under 5-10 keV Ne+ ion bombardment at a normal to the face. The ejection angles, energies, and masses of secondary ions were anialyzed using an installation which comprised a sector electrostatic energy analyzer with a 60° deflection angle and a magnetic mass-spectrometer. The angular distributions of the 115in+ and 65Cu...

Mass dependence of nitride sputtering

A molecular dynamics simulation was performed to study the sputtering yield Y for BN, AlN and GaN polycrystals of wurtzite structure as a function of the masses m 1 of bombarding ions with energies from 200 to 2000 eV. A nonmonotonic behavior of the Y(m 1) curve was obtained for the irradiation by low-energy ions, the curve having a maximum with a position being dependent on m2/m1 (m2 is the average mass of atoms in a compound). For AlN and GaN the maximum was observed at m2/m1 = 2, and for BN at m2/m1 = 1. The effect of the mass of bombarding ions on the mean energies and energy spectra of sputtered particles, the depth of sputtering origin, and the generation of emitted atoms for nitrides was also investigated and discussed.

Models of single crystal sputtering

Abstract Analytical models of single crystal sputtering, including consideration of focusons, channelling and transparency, are reviewed and computer calculations, dealing with both binary models and dynamical models involving different numbers of interacting particles, are considered in greater detail. Results of all calculations are discussed and compared with experimental data.