DC Magnetron Deposition Research Articles

Formation of zinc oxide composites of doxycycline with high antibacterial activity based on DC-magnetron deposition of ZnO nanoscale particles on the drug surface

Formation of zinc oxide composites of doxycycline with high antibacterial activity based on DC-magnetron deposition of ZnO nanoscale particles on the drug surface

FeTiB nanocrystalline films: Static and dynamic magnetic properties in accordance with phase composition and magnetic structure

Nanocrystalline Fe100–56.8Ti0–13.5B0–34.2 films 1.4 µm thick are prepared by dc magnetron deposition on glass substrates. The structure and magnetic properties of the films are comprehensively characterized and analyzed. The lattice parameter and the grain size of the bcc Fe-based phase (2-25 nm), parameters of the stochastic magnetic structure (the relative size and the effective anisotropy field of stochastic domains D1/2<Ha> and the local magnetic anisotropy field at the grain scale), saturation magnetization Ms, coercive field Hc, static permeability mst, and ferromagnetic resonance frequency fr of the films are quantitatively estimated and their interrelations are studied. As Ti and B contents increase, the phase composition of the films changes in accordance with the sequence αFe - αFe(Ti) - αFe(Ti) + TiB2 - amorphous, wherein Ms decreases from 2.1 to 0.3 T. The Hc values vary in the interval 7–70 Oe determined by the D1/2 <Ha> field or by other magnetic anisotropy sources. The μst values vary in the interval 20–140. The μst values obtained by the Lorentzian dispersion law adequately fall within the range of the calculated permeabilities, which is limited by the coercive field obtained from the hysteresis loops and the anisotropy field determined by Kittel equation. The μst values of the films are kept up to the frequencies of at least 1.5 GHz. The frequency dependences of the permeability of the films are analyzed taking into account the influence of skin effect and are considered in terms of Acher’s law. The obtained values of the Acher’s constant (less than 0.3) indicate the possibility of reaching the higher values of μst and fr at the expense of elimination of the perpendicular anisotropy, in particular, via the formation of thinner films as compared to the films under study (1.4 µm thick). According to the available literature data, the presented investigations, using the FeTiB films as an example, were performed for the first time.

FeTiB film materials: Dependence of the magnetic properties and magnetic structure on the phase and structural states

The Fe99.2÷56.6Ti0÷13.2B0÷34 films were prepared by dc magnetron deposition on glass substrates. X-ray diffraction analysis was used to determine the phase composition, volume fractions of formed crystalline phases, their grain sizes and microstrains on the grain scale. The magnetic hysteretic properties, saturation induction Bs (2.1–0.3 T), coercive field Hc (0.6–6 kA/m), relative remanence Br/Bs (0.07–0.37), were determined using measured hysteresis loops. Their shapes indicate the existence of intergranular exchange interaction in all studied films. The magnetic structure parameters of the films were determined by correlation magnetometry. All films are characterized by a stochastic magnetic structure. The magnetic properties and the magnetic structure parameters of the films are substantiated by their phase and structural states. The values of the local parameters of the magnetic structure (rms local anisotropy field D1/2Ha and exchange field HR) follow the parameters of the grain (lattice parameter and grain size), while the macroscopic parameters (Hc and rms stochastic domain anisotropy field D1/2<Ha> ) have a more complex behavior.

FeZrN Films: Magnetic and Mechanical Properties Relative to the Phase-Structural State.

The paper presents results of investigation of Fe65.3–100Zr34.7–0N7.5–0 films prepared by dc magnetron deposition on glass substrates and subsequent 1-hour annealing at temperatures of 300–600 °C. The influence of the chemical and phase compositions and structure of the films, which were studied by TEM, SEM, XRD, and GDOES, on their mechanical properties determined by nanoindentation and static magnetic properties measured by VSM method is analyzed. The studied films exhibit the hardness within a range of 14–21 GPa, low elastic modulus (the value can reach 156 Gpa), and an elastic recovery of 55–83%. It was shown that the films are strong ferromagnets with the high saturation induction Bs (up to 2.1 T) and low coercive field Hc (as low as 40 A/m). The correlations between the magnetic and mechanical properties, on one hand, and the chemical composition of the films, their phase, and structural states as well, on the other hand, are discussed.

Zinc Oxide Composites of Doxorubicin in the Form of Coating, Composite Films and Gels with a High Antitumor Activity and Low Toxicity

This work is devoted to the formation doxorubicin (DOX) zinc oxide composites in the form of coating (DOX + ZnO), hydrogels and composite films of DOX with polyvinyl alcohol (DOX + PVA + ZnO) by DC-magnetron deposition of ZnO nanoscale particles (ZnO NPs) on their surfaces (DOX, DOX + PVA) with higher (two times and more) antitumor activity and considerable smaller toxicity at low doses of DOX in compositions compared to the initial drug. Using the methods of spectroscopy, atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray Powder Diffraction (XRD), the role of ZnO NPs size on the antitumor activity of doxorubicin zinc oxide compositions is shown. AFM shows presence of many ZnO NPs on the surface DOX. A comparison of the FTIR spectra of DOX and its zinc oxide compositions has shown the presence of new bands of OH valence and deformation vibrations. It is possible to assume that interaction between ZnO and DOX takes place in the form of hydrogen bond, promoting the complexes formation. It is possible that both synergic and hydrogen-bonding ZnO with DOX increase the antitumor activity.

Electrochemical characteristics of NixN thin films deposited by DC and HiPIMS reactive magnetron sputtering

This study deals with the DC and HiPIMS reactive magnetron deposition process using a pure nickel target (99.995%) in an Ar-N2 gas mixture with varied nitrogen gas flow and bias voltage (floating or -100 V). The characterization of the NiN films has been carried out by X-ray diffraction (XRD), X-ray photoelectrons spectroscopy (XPS) and Energy dispersive X-ray Spectroscopy (EDXS). XRD measurements have highlighted the deformation of the Ni cubic cell as a function of nitrogen content, and a mixture of nitrided phases (Ni4N, Ni3N and Ni2N) appears for 20% N2 in the discharge. XPS and EDX are well correlated and permit us to determine three zones: metallic between 0 and 20% N2, Ni4N between 20% and 42% N2 and finally Ni3N for N2 above 50%. These three zones are in good agreement with deposition rates and optical emission spectroscopy measurements. Cyclic voltammetry has been performed in a conventional three-electrode cell using neutral, alkaline and acidic aqueous electrolytes. The NixN electrochemical behavior shows a pseudocapacitive charge storage mechanism in LiNO3 and KOH electrolytes using an appropriate voltage window, suitable for supercapacitors, whereas NixN exhibits reversible faradaic redox peaks beyond one potential in KOH, depicting NixN film as a battery-type electrode.

COMPARISON OF THE Ti/n-GaAs SCHOTTKY CONTACTS’ PARAMETERS FABRICATED USING DC MAGNETRON SPUTTERING AND THERMAL EVAPORATION

We have fabricated the Ti/[Formula: see text]-type GaAs Schottky diodes (SDs) by the DC magnetron deposition and thermal evaporation, cut from the same GaAs substrates, and we have made a comparative study of the current–voltage ([Formula: see text]–[Formula: see text]) measurements of both SDs in the measurement temperature range of 160–300[Formula: see text]K with steps of 10[Formula: see text]K. The barrier height (BH) values of about 0.82 and 0.76[Formula: see text]eV at 300[Formula: see text]K have been obtained for the sputtered and evaporated SDs, respectively. It has been seen that the apparent BH value for the diodes has decreased with decreasing temperature obeying the single-Gaussian distribution (GD) for the evaporated diode and the double-GD for the sputtered diode over the whole measurement temperature range. The increment in BH and observed discrepancies in the sputtered diode have been attributed to the reduction in the native oxide layer present on the substrate surface by the high energy of the sputtered atoms and to sputtering-induced defects present in the near-surface region. We conclude that the thermal evaporation technique yields better quality Schottky contacts for use in electronic devices compared to the DC magnetron deposition technique.

Effect of Pt, Pd, Au additives on the surface and in the bulk of tin dioxide thin films on the electrical and gas-sensitive properties

The microstructure and properties of thin (∼100 nm) SnO2 films with noble metals Pt, Pd, Au additives, grown by dc magnetron deposition are studied. It is shown that the introduction of additives into the bulk and the deposition of dispersed catalysts on the semiconductor surface make it possible to control the sensor parameters in pure air and upon exposure to reduction (CO, H2, CH4) and oxidation (NO2) gases. Possible mechanisms for the effect of Pt, Pd, Au on the bulk and surface properties of tin dioxide are discussed. The technological conditions for film growth, which provide the selective detection of low concentrations (10–100 ppm) of CO and H2, below-explosive concentrations (0.5–2.5 vol %) of methane, and trace concentrations (0.05–5 ppm) of NO2 are determined.

High-sensitive hysteresisless spin valve with a composite free layer

Method of dc magnetron deposition has been used to prepare metallic nanostructures of the (Si, Al2O3, glass)/Ta/[NiFe/CoFe]/Cu/CoFe/(FeMn, MnIr)/Ta spin-valve type with a composite “free layer” Ni80Fe20/Co90Fe10. A three-stage method of decreasing hysteresis of the free layer has been suggested. The dependence of the magnitude of the giant magnetoresistance and hysteresis has been investigated depending on the angle between the direction of the easy magnetization axis of the free layer and the direction of the applied magnetic field in the plane of layers. It is shown that in the spin valves studied the hysteresis can be reduced to a few tenths of an oersted at the magnitude of the magnetoresistance more than 8%. In the case of a spin valve with an antiferromagnet Fe50Mn50 the magnetoresistive sensitivity in the range of the hysteresisless variation of the magnetoresistance was equal to 1%/Oe, whereas the maximum sensitivity in the presence of a hysteresis exceeded 6%/Oe. A greater sensitivity (2.5%/Oe) at the magnitude of the free-layer hysteresis of 0.6 Oe was obtained for spin valves on the basis of the antiferromagnetic Mn75Ir25 alloy. For them, the maximum magnetoresistance was equal to 11.6%.

Comprehensive study of the conditions for obtaining hydrogenated amorphous erbium- and oxygen-doped silicon suboxide films, a-SiO x :H 〈Er,O〉, by dc-magnetron deposition

The results of a comprehensive study of the conditions for growing a-SiO x :H 〈Er,O〉 films are presented. The effect of the composition of various erbium-containing targets (a-SiO x :H , ErO x , Er2SiO5, Er2O3, and Er), substrate temperature, and annealing temperatures in argon, air, and under conditions of SiH4 + Ar + O2 plasma glow is studied. In order to obtain a-SiO x :H 〈Er,O〉 films with the highest photoluminescence intensity of erbium ions, it is recommended for the following technological conditions to be used: the substrate holder should be insulated from dc-magnetron electrodes and the working gas mixture should include silane, argon, and oxygen. Single-crystal silicon and metal erbium should be used as targets. The erbium target should be placed only in the Si-target erosion zone.

Lateral variation of target poisoning during reactive magnetron sputtering

The reactive gas incorporation into a Ti sputter target has been investigated using laterally resolving ion beam analysis during dc magnetron deposition of TiN in an Ar∕N2 atmosphere. At sufficiently low reactive gas flow, the nitrogen incorporation exhibits a pronounced lateral variation, with a lower areal density in the target racetrack compared to the target center and edge. The findings are reproduced by model calculations. In the racetrack, the balance of reactive gas injection and sputter erosion is shifted toward erosion. The injection of nitrogen is dominated by combined molecular adsorption and recoil implantation versus direct ion implantation.

Transport and magnetic properties of DC-magnetron sputterred Ln 0.7Mn 1.3O 3− δ thin films

Epitaxial thin films of Ln 0.7Mn 1.3O 3− δ have been grown on [0 0 1]-oriented LaSrAlO 4 substrates by DC-magnetron deposition. Magnetization, resistivity, thermopower, and magnetic resonance spectra are investigated over a range of temperatures and magnetic fields. The magnetic polaron theory is used, phenomenologically, to provide a quantitative explanation of transport properties of the oxidized films both above and below Curie temperature T C. The main assumption is that metal–insulator transition near T C is due to a crossover in polaronic mobility. At low temperatures we observe an anisotropy of magnetic resonance spectra, both resonance field and linewidth. To qualitatively account for all the observations (resistivity, thermopower, and magnetic resonance spectra) we suggest an intrinsic electric and magnetic inhomogeneity of the samples.

Three-dimensional Monte Carlo simulation of sputtered atom transport in the process of ion-plasma sputter deposition of multicomponent thin films

An algorithm for Monte Carlo simulation of sputtered atom transport during ion-plasma sputtering was developed. The experimentally determined initial energy distribution of sputtered atoms, the influence of the background gas mixture and the real equipment geometry of the magnetron sputtering system were taken into account. To describe the collision between sputtered atoms and background gas atoms, the Firsov interatomic potential with Nikulin screen function was used. In simulations, the equipment geometry and deposition conditions were chosen corresponding to those of DC magnetron deposition of Cu and YBa 2Cu 3O 7- x thin films. The spatial, energetic and angular distribution of sputtered atoms on the substrate surface, target and chamber’s walls were calculated. The obtained results are in good agreement with experimental ones. The presented simulation procedure is useful in daily research work to choose the optimal deposition conditions for both on- and off-axis magnetron deposition systems.

Growing multilayer gradient thin films via in situ neurocomputing

Multiple-layer thin films of less than 2 μm are presently typically deposited via mechanical manipulation of substrates. Interlayer gradients are typically accomplished by the rotation of substrates between two or more material deposition sources. Film deposition rates are often maintained with limited instrumentation, and no feedback control. Additionally, most tribological hard films deposited on relatively soft substrates need to be deposited with a buffer or interface layer in order to bond a particular film to a substrate. Often, this buffer layer is deposited by manually ramping rotation speeds or source deposition rates, increasing film variability. This research is focused on identifying and relating observed process characteristics to the resulting material chemistry and structure, with a goal of dynamically controlling the material characteristics for multilayer films using in situ neurocomputing. Of specific interest is the ability to grow multilayer diamond-like carbon (DLC)-ceramic–metal films. DLC films deposited by pulsed laser deposition (PLD), combined with the reactive gas DC magnetron deposition of titanium to create Ti–TiN–DLC or Ti–TiC–DLC material gradients will be the focus of this work. In situ laser-induced florescence (LIF) spectroscopy and a quartz crystal microbalance are used for in situ plume sensing with the aim of controlling the film deposition rates and the resulting deposited structure.

Meeting the process challenges for spin-valve fabrication on an industrial scale

We investigated industrial deposition processes for spin-valve giant magneto resistance (GMR) multilayers. We compared rf diode with dc magnetron deposited films, as well as films deposited in a cluster tool equipped with single target process modules and a multitarget module. It is found that the best MR response is obtained by using dc magnetron deposition in a multitarget process module, as this minimizes contamination by background gas atoms and interface mixing due to self-biasing of the substrate. Furthermore, dc magnetron deposition allows accurate control of the deposition time, and thus the thickness of 10–100 Å films. Applying this method to spin-valve deposition results in a controllability of 0.5 Å, a uniformity around 1% (=1σ) over 150 mm wafers and repeatability around 1%. This implies that this process meets the requirements for production of GMR magnetic read heads.

A combined AES, resonant photoemission and EELS study of in-situ grown titanium nitride

Samples of titanium nitride were grown in an Ar N atmosphere with various Ar N gas ratios using reactive DC magnetron deposition onto stainless steel and silicon substrates. The samples were transferred to the analysis position in-situ and were studied there using AES, EELS and synchrotron-radiation excited UPS. Using AES, the composition of the samples was found to vary with the Ar N gas ratio, as expected. Changes in the hybridised Ti 3 d N 2p band seen via UPS agreed with the theoretical prediction that the band narrows as the nitrogen concentration is reduced. A large resonance in the Ti 3d band was observed at ∼73 eV, which is probably associated with the Ti 3s level. The UPS and EELS data is consistent with vacancies being present on the titanium sublattice. The EELS data displayed low-energy loss peaks which shifted to higher loss energies as the nitrogen concentration in the film was lowered. These loss peaks can be explained by a screened Drude plasmon loss rather than by intraband transitions. The intensity of the loss peaks was much weaker than previously reported, with attendant implications for explanations of the shape of the Ti 2p photoelectron peak observed in XPS.

Effect of deposition conditions on the characteristics of reactively sputtered titanium nitride films

A study of the reactive DC magnetron deposition of TiN x films has been performed, from nitrogen/argon mixtures containing from 5 to 50% nitrogen and with substrate temperatures from 150 to 700 °C, The microhardness, chemical composition, crystallographic texture and deposition rate of the films were studied in detail. At a substrate temperature of 600 °C, deposition rate increased as the gas nitrogen content decreased. From 20 to 50% nitrogen, the nitrogen content of the films increased as the nitrogen content in the gas decreased. The film microhardness increased with increasing nitrogen/argon ratio. As substrate temperature was decreased, the nitrogen content in the films increased and microhardness decreased. Films grown below ca. 500 °C showed (111) orientation. For higher temperatures and from 50% nitrogen atmospheres, the dominant orientation changed to (200).

Processes on the target, discharge and NbN film behaviour in reactive dc magnetron deposition

The preparation of NbN coatings by reactive dc magnetron sputtering and the effects of the ratio of nitrogen to total gas mixture flow rates on the process are studied. The range of the ratios was from 2 to 20%. The influences of the nitrogen gas flow rate in the working gas mixture Ar+ N 2 were investigated on the argon gas flow rate, on the partial pressure of nitrogen, on the dc discharge characteristics and deposited film properties under the various process conditions (e.g. variation of pumping speed from 45 to 115 l/s, discharge current from 100 to 700 mA) in reactive dc magnetron deposition of NbN films. A simple model of nitrogen coverage of the Nb target was used to interpret experimental results. The influence of rapid thermal annealing of NbN coatings on their properties was investigated in the temperature range from 850 to 1000 °C. The correlation between technological parameters and coating properties, structure and composition were established.

To the Kinetics of Nitrogen Incorporation during dc Magnetron Deposition

AbstractInvestigations of nitrogen incorporation during film deposition by dc magnetron sputtering with a CrSiAl target in Ar/N2 mixtures have been carried out in the range of the metallic mode. The rate of the nitrogen consumption is proportional to the nitrogen partial pressure during deposition and to the amperage. The corresponding rate constant decreases with the argon pressure. Furthermore, the condensation rate of the target species decreases with the nitrogen partial pressure and is determined by the rate constant of the nitrogen consumption. The experimental results are explained by a 4‐stepped reaction sequence of nitrogen incorporation consisting in (1) ionization, (2) ion bombardment of the target and formation of a coverage by plating, (3) removal of the coverage by the sputter process, (4) condensation on the substrate.

Design of variable phase velocity kinetic inductance delay lines and their measured characteristics when fabricated by a simple Nb based process

A simple design for superconducting kinetic inductance delay lines is presented. Delay lines were fabricated with a thin-film process involving only DC magnetron deposition and anodization of Nb. Phase-velocity measurements demonstrated wave slowing to less than 1/150 of the velocity of light in free space with associated impedances in the ohm range. Phase velocity changes on lines which were in physical proximity to long Josephson junctions and normal conducting lines were investigated. Variations larger than 10% of the equilibrium value were observed with junction-coupled lines under bias application. Locally heated lines exhibited changes exceeding a factor of two. Loss and phase velocity were determined as a function of bias conditions in both cases. Measured line loss was within expectations.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>