A. S. Dzhumaliev

Magnetron sputtering of thin Cu(200) films on Ni(200)/SiO2/Si substrates

The possibility of oriented growth of thin copper films with a (200) texture on a SiO2/Si substrate by magnetron sputtering in medium vacuum is demonstrated for the case when a predeposited nickel layer with a (200) texture serves as an orienting sublayer.

Refractive index and lattice constant of zinc oxide films modified in a low-temperature plasma

The crystallographic and optical properties of ZnO films obtained in the recombination burning zone of a low-temperature plasma are investigated. The refractive index is determined, and its correlation with the lattice constant along the c axis is found. A planar homogeneous structure consisting of two ZnO films with different refractive indices is fabricated to demonstrate areas of application of the technique suggested.

Synthesis of ordinary-and inclined-texture zinc oxide films in an inhomogeneous gas-discharge plasma

Zinc oxide films having ordinary and inclined texture were grown on extended amorphous substrates. It was shown that a desired structure can be provided by controlling charged particle fluxes with the substrate remaining parallel to the target plane. Experiments were performed in a dc magnetron sputterer in a mixture of argon and oxygen. The textured films were studied by X-ray diffraction and by exciting longitudinal and shear bulk acoustic waves.

The formation of the (200) and (110) textures in iron films prepared by magnetron sputtering

The effect of working-gas pressure on the texture of iron films on Si(100)/SiO2 substrates prepared by magnetron sputtering at room temperature is studied. It is shown that a change in working-gas pressure from 1.33 to 0.09 Pa leads to a change in the texture of the films from (110) to (200), which is accompanied by transition from a columnar to quasi-homogeneous microstructure of the films. It is found that the surface roughness of the film nonmonotonically depends on working-gas pressure and has a maximum in a pressure range corresponding to the coexistence of phases with the (110) and (200) textures in the film.

Effect of annealing temperature and rate of sputtering on the magnetic properties and microstructure of the polycrystalline nickel films with (200) texture

The dependences of the magnetic properties and morphology of polycrystalline nickel (Ni) films with the (200) texture that are fabricated using the dc magnetron sputtering on the SiO2/Si(100) substrates on sputtering rate annealing temperature T, and film thickness d are analyzed. It is demonstrated that an increase in the sputtering rate from 17 to 35 nm/min does not affect the saturation magnetization 4πM and ferromagnetic resonance line width ΔH but leads to a significant increase in the coercivity Hc for the films whose thickness d is greater than critical thickness dcr (d > dcr). It is also demonstrated that dcr depends on both sputtering rate and annealing temperature. The films with the thickness d > dcr exhibit the stripe domain structure whose period increases with increasing d and rate v. The annealing of the films with d ≥ 40 nm at T ≈ 200–400°C results in an increase in ΔH and Hc by a factor of 2–4, an increase in 4πM by 25%, an increase in grain size ξ by a factor of 20–30, and the formation of the stripe domain structure in the films that do not exhibit such structure prior to annealing and substantial strengthening of the (200) texture.

Effect of bias voltage polarity of a substrate on the texture, microstructure, and magnetic properties of Ni films prepared by magnetron sputtering

The influence of the bias voltage polarity Us on microstructure, crystallographic texture and magnetic properties has been investigated for Ni films with a thickness of ≈15–420 nm, which are obtained via magnetron sputtering at a working gas pressure P corresponding to the collision-deficient flight mode of atoms of the sputtered target between the target and the substrate. The Ni(111)-textured films have been shown to form at Us ≈–100 V, whose microstructure and magnetic parameters are almost unchanged with a thickness. In contrast, the Ni(200) films are formed at Us ≈ +100 V, whose magnetic properties and micro-structure depend significantly on the thickness d that manifests in a critical thickness d* ≈ 150 nm, when the structure of the film becomes inhomogeneous in the thickness, the remagnetization loops are changed from rectangular to supercritical with the formation of the band domain structure.

Surface roughness and magnetic properties of Co/SiO2/Si(100) polycrystalline films deposited via DC magnetron sputtering

For polycrystalline films of cobalt that have the thickness t ≈ 1.3–133 nm and that are deposited via DC magnetron sputtering on SiO2(0.1 μm)/Si(100) substrates, surface-roughness root-mean-square amplitude σ and surface correlation length ξ, which characterize the roughness of film surfaces, as well as saturation magnetization 4πM0, width of ferromagnetic-resonance line ΔH, coercitivity HC, and saturation fields HS, are studied as functions of film thickness t. It is shown that the behavior of dependences HC(t) and HS(t) coincides with the behavior of dependence σ(t)/t, whereas the behavior of 4πM0(t) depends on ratio t/σ(t). The dependence of the FMR line width on the film thickness, ΔH(t), is characterized by a minimum of ΔH ≈ 60 Oe present in the region of thicknesses of 30 to 60 nm. The behavior of dependence ΔH(t) is determined by ratio σ(t)/t at small thicknesses t ≤ 5 nm and by the behavior of σ(t) at t ≥ 5 nm.

Zinc Oxide Molecules and Clusters Formed in a Quasiclosed Volume of Reactive Gas-Discharge Plasma

Plasma-deposited zinc oxide films were studied and it was established that oxide molecules may form and their clusters nucleate within a recombination burning zone in the volume of plasma, provided that the ion range does not exceed the size of a discharge chamber. The nucleation zone is rather narrow and its position depends on the gas pressure in the chamber. The zinc oxide films grown in this zone possess a texture with small misorientation angle and are characterized by small thickness of the nucleation texture and high piezoelectric activity.

Magnetic crystallographic anisotropy of Fe/GaAs(100) epitaxial films

An investigation was made of the anisotropic properties of Fe films obtained by molecular-beam epitaxy on GaAs(100) substrates. It is shown that at thicknesses t=40–50 Å the Fe films begin to exhibit cubic magnetic anisotropy. At thicknesses t>100 Å the first constant of cubic anisotropy K1 has values similar to those for “bulk” Fe single crystals. Films of intermediate thickness 50<t<100 Å possess both isotropic and anisotropic phases.

Formation of textured Ni(200) and Ni(111) films by magnetron sputtering

The effect of the working gas pressure (P ≈ 1.33–0.09 Pa) and the substrate temperature (Ts ≈ 77–550 K) on the texture and the microstructure of nickel films deposited by magnetron sputtering onto SiO2/Si substrates is studied. Ni(200) films with a transition type of microstructure are shown to form at growth parameters P ≈ 0.13–0.09 Pa and Ts ≈ 300–550 K, which ensure a high migration ability of nickel adatoms on a substrate. This transition type is characterized by a change of the film structure from quasi-homogeneous to quasi-columnar when a film reaches a critical thickness. Ni(111) films with a columnar microstructure and high porosity form at a low migration ability, which takes place at P ≈ 1.33–0.3 Pa or upon cooling a substrate to Ts ≈ 77 K.