K.F. Minnebaev

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.

Anisotropy of sapphire single crystal sputtering

We have studied the spatial distribution of particles sputtered from the base (0001) plane of a sapphire single crystal with trigonal crystalline lattice (α-Al2O3) that can be considered a superposition of two hexagonal close packed (hcp) structures–the ideal sublattice of oxygen and a somewhat deformed sublattice of aluminum. It is established that the particles sputtered from the base plane of sapphire are predominantly deposited along the sides of an irregular hexagon with spots at its vertices. The patterns of spots have been also studied for sputtering of particles from the (0001) face of a zinc single crystal with the hcp lattice. The spots of sputtered Zn atoms are arranged at the vertices of concentric equilateral hexagons. In both cases, the observed anisotropy of sputtering is related to focused collisions (direct and assisted focusing) and the channeling process. The chemical composition of spots has been determined in various regions of sputtered sapphire deposition. The results are discussed in comparison to analogous earlier data for secondary ion emission from an α-Al2O3 single crystal.

On the Energy Spectra of Secondary Ions Emitted from Silicon and Graphite Single Crystals

Secondary ion emission from silicon and graphite single crystals bombarded by argon ions with energies E0 varied from 1 to 10 keV at various angles of incidence α has been studied. The evolution of the energy spectra of C+ and Si+ secondary ions has been traced in which the positions of maxima (Emax) shift toward higher secondary-ion energies E1 with increasing polar emission angle θ (measured from the normal to the sample surface). The opposite trend has been observed for ions emitted from single crystals heated to several hundred degrees Centigrade; the Emax values initially remain unchanged and then shift toward lower energies E1 with increasing angle θ. It is established that the magnitude and position of a peak in the energy spectrum of secondary C+ ions is virtually independent of E0, angle α, and the surface relief of the sample (in the E0 and α intervals studied). Unusual oscillating energy distributions are discussed, which have been observed for secondary ions emitted from silicon (111) and layered graphite (0001) faces. Numerical simulations of secondary ion sputtering and charge exchange have been performed. A comparison of the measured and calculated data for graphite crystals has shown that C+ ions are formed as a result of charge exchange between secondary ions and bombarding Ar+ ions, which takes place both outside and inside the target. This substantially differs from the ion sputtering process in metals and must be taken into account when analyzing secondary ion emission mechanisms and in practical applications of secondary-ion mass spectrometry.

Improved angle and energy resolved secondary ion spectrometer

Abstract An apparatus for angle and energy resolved SIE with improved characteristics is designed and created. The apparatus is based on the concept of a movable energy analyser with fixed mass analyser. The energy analyser consists of a first forming 5 element lens, 180° hemispherical electrostatical deflector, 90° hemispherical electrostatical deflector, and transport lenses. The transmission energy bandwidth is kept constant. The sputtered secondary ions are registered within a solid angle of Ω = 6°. The polar angle of registration may be varied from θ = 15 to 90°.