Reactive Magnetron Deposition Research Articles

Reactive magnetron deposition of YAG:Ce phosphor coatings in the metallic mode

The possibility of YAG:Ce3+ coatings phosphor formation by reactive magnetron deposition during sputtering of metal targets in an atmosphere of argon and oxygen activated by a radio-frequency source of inductively coupled plasma has been studied. The installation consists of three middle-frequency magnetrons with Y, Al and Ce targets with power of 1000, 1570 and 150 W, respectively. The (Y–Al–O):Ce coatings were deposited in metal and oxide sputtering modes of yttrium and aluminium targets. The coating deposition rate on the planetary rotating substrates in the metallic sputtering mode reaches of 0.67 nm/s. This is about an order of magnitude higher compared to the oxide sputtering mode and the method of radio-frequency magnetron sputtering of ceramic targets commonly used to deposit such coatings.Characterization of the elemental and phase composition of the coatings showed the YAG:Ce crystal structure formation during annealing both in air at 1100 °C and in a nitrogen atmosphere at 1200 °C. Cathodo- and photoluminescent spectroscopy was used for study of YAG:Ce thin films emission properties. The emission properties of YAG:Ce correspond to the radiation transition in Ce3+ ions. It was found that the intensity of both types of luminescence turned out to be slightly higher for samples annealed in air. It enhanced with increasing coating thickness in the considered range from 1.8 to 7.0 μm. The suggested approach could be potentially used for luminescent coatings formation with high level of the emission properties.

Optical and electrophysical properties of nitride TiAlSiN and carbonitride TiAlSiCN coatings: influence of reactive magnetron deposition regimes

The development of thin-film thermal control coatings for small spacecraft is relevant. Coatings based on titanium nitride are capable of functioning in unfavorable conditions of near and deep space, due to their high resistance to the irradiation by high-energy particles. Using the reactive magnetron sputtering method, the nanostructured TiAlSiN and TiAlSiCN coatings were formed on the substrates of silicon oxide (SiO2), glass-ceramic CT-1 and single-crystalline silicon (Si(100)). A study of the electrophysical and optical properties of the formed coatings was carried out. The deposited coatings demonstrate a good reflectivity in the infrared range of spectrum (700–2000 nm), what is important for reducing the overheating of the spacecraft (SC) under the influence of the direct sunlight. In the visible range of spectrum (400–700 nm), a low level of total Rtotal reflection is observed. This is promising for satellites designed to observe the Earth’s surface. The values of solar absorption coefficients αs, emissivity coefficients ε0, ratios αs/ε0, as well as the equilibrium temperature Tр for the samples under study were obtained. The values of resistivity ρ and surface resistance R□, electron concentration N and electron mobility μ were determined. It has been discovered that TiAlSiN, TiAlSiCN films are electrically conductive: ρTiAlSiN = (92÷4260) ∙ 10–7 Ω ∙ m, ρTiAlSiCN = (51÷2360) ∙ 10–7 Ω ∙ m. It has been found that adding carbon to the coating composition reduces the resistance. The obtained nanostructured coatings of TiAlSiN nitride and TiAlSiCN carbonitride can be used as temperature control coatings for small spacecrafts.

Плёнки FeZrN: статические и СВЧ магнитные свойства

The phase-structural state, magnetic structure parameters, static and microwave magnetic properties of Fe81 – 74Zr2 – 5N17 – 21 films prepared by reactive magnetron deposition were studied. As the Zr and N contents increase, the film structure changes from, so-called, mixed structure (grain size 3 – 6 nm of nanocrystalline α-Fe(Zr,N) + fcc nitride) to amorphous one. The film magnetic structure parameters (effective anisotropy field of stochastic domains D1/2〈Ha〉 = 11.8 ± 8 Oe and effective local anisotropy field D1/2Ha = 880 ± 700 Oe), saturation magnetization Ms (1.8 ± 0.3 T), coercive field Hc (11 ± 2 Oe), and the real permeability µ′ (80 ± 30), retaining its value at frequencies up to 3 GHz, were determined. The values of the initial permeability µ0 (70 ± 21) obtained from the hysteresis and the real permeability µ′ (80 ± 30) obtained from microwave measurements are in good agreement. The correlation between the static magnetic properties, the stochastic magnetic structure parameters and the real permeability µ′ was considered. There is no any sign on ferromagnetic resonance in the studied frequency range. However the Acher’s coefficient value (less than 0.38) for this frequency range indicates the possibility of ferromagnetic resonance at higher frequencies.

Nanostructured TiAlCuN and TiAlCuCN coatings for spacecraft: effects of reactive magnetron deposition regimes and compositions.

Spacecraft are exposed to a number of factors in the outer space: irradiation by electron flows, high-energy ions, solar electromagnetic radiation, plasma irradiation, and a stream of meteorite particles. All these factors initiate various physical and chemical processes in spacecraft materials, which can eventually lead to failure. To ensure reliable operation of spacecraft, it is necessary to use protective coatings and special radiation-resistant materials. TiAlCuN and TiAlCuCN coatings were formed by reactive magnetron sputtering on different substrates: single-crystal silicon and Titanium Grade 2 wafers. Nitrogen was used as a reactive gas to form nitride coatings and acetylene was used to form carbonitride coatings. The elemental composition was studied by energy-dispersive X-ray (EDX) spectroscopy. The structural-phase state of the coatings was examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Mechanical properties, such as hardness and Young modulus, were investigated by nanoindentation using a CSM Instruments Nanohardness Tester NHT2. The influence of deposition parameters, such as Ti and Al contents, the degree of reactivity α, and carbonitride formation on the structure and their mechanical properties were considered. It was detected that Cu addition to the coatings has effects on crystallite and growth column size refinement in comparison with the TiAlN and TiAlCN analogues due to its segregation along crystalline boundaries, and thus, imparts better mechanical characteristics. The hardness of TiAlCuN and TiAlCuCN coatings varies in the range of H = 25-36 GPa and Young modulus - E = 176-268 GPa. The impact strength index and the H/E* ratio, as well as the plastic deformation resistance index H3/E*2, were calculated. Due to their high mechanical properties, the formed nitride and carbonitride coatings are promising for use in space technologies.

Structural, ferroelectric and magnetic properties of lead ferrite (Pb2Fe2O5) thin films synthesized by reactive magnetron deposition

Lead ferrite (Pb2Fe2O5) thin films were deposited by reactive magnetron sputtering in the (500 - 600)°C temperature range. At room temperature, thin films exhibited remnant polarization of ~60 µC/cm2 and EC ~ 90 kV/cm. With the increase of synthesis temperature, ferroelectric properties deteriorate and formed capacitors become lossy. X-ray diffraction pattern demonstrated formation of lead ferrite phase, although lead and iron oxides could not be avoided. It was determined by atomic force microscopy (AFM), that with the increase of temperature, average surface roughness decreases from 25.9 nm to 2.7 nm, possibly due to the surface diffusion. Images of scanning electron microscopy complement AFM data where smoother surfaces are visible. Measured temperature dependences of dielectric permittivity indicated Curie temperature at 783 K. Magnetic susceptibility measurement confirmed Neel magnetic ordering temperature around 540 K.

Технология магнетронного нанесения высокобарьерного относительно кислорода наноразмерного покрытия из оксида алюминия на рулонную лавсановую пленку

The paper introduces the development of the technology of reactive magnetron deposition of a nanosized aluminum oxide layer on a roll PET film, which provides a low specific permeability relative to oxygen. We describe a large-size magnetron deposition facility and its optimal operating modes, as well as the sequence of operations performed. Within the research, we found that various parameters of magnetron deposition of aluminum oxide affect the characteristics of the nanosized layer. The thicknesses of oxide layers were measured in the range of 20--80 nm, the roughness of their surfaces and their structures and reliefs were estimated. Furthermore, we established the experimental dependence of the specific permeability relative to the oxygen of the oxide layer on the PET substrate on its thickness in the range of 20--80 nm. The study gives its qualitative explanation and describes the specific energy consumption

The Effect of Aluminum Dopant Amount in Titania Film on the Memristor Electrical Properties

In a promising nanoelectronics device, namely, memristor based on metal oxides, there are many intermediate states with different conductivity between the limits of highly conductive and low-conducting states. These intermediate states can be used in the processes of associative learning of a neural network based on memristor synapses and simultaneous processing of input pulses, which consists in their weighing and summation in the neuroprocessor. By the method of simultaneous magnetron sputtering of two cathodes in a reactive oxygen environment, thin films of mixed oxides with a different mole ratio of titanium and aluminum were obtained. A method for obtaining a mixed oxide with a specified metal fractions by controlling the sputtering rates of cathodes using acoustic piezoelectric sensors is described. It is shown that the introduction of Al into titanium oxide improves the electrophysical characteristics of the memristor. The existence of an optimal fraction of Al dopant maximizing the memristor resistance ratio of the high-resistive and low-resistive states is established. The results indicate that the method of reactive magnetron deposition of mixed metal oxide by simultaneous sputtering of two cathodes provides a more uniform distribution of elements across the thickness of the active layer compared with the atomic layer deposition method. The uniform distribution is necessary to improve the stability of the memristor. It can be expected that in the memristors on mixed oxides TixSc1-xOy, HfxSc1-xOy, HfxY1-xOy, HfxLu1-xOy, ZrxSc1-xOy, ZrxY1-xOy, ZrxLu1-xOy an optimal dopant fraction corresponding to the maximally increased ratio of resistances in the high-resistance and low-resistance states will also be observed. Moreover, memristors on films with pure hafnium and zirconium oxides have a much larger range of resistive switching than titanium oxide.

Growth and characterization of PbI2-decorated ZnO nanowires for photodetection applications

In this study, we demonstrated for the first time the growth of ZnO nanowires (NWs) decorated with highly crystalline few-layer PbI2 and fabricated two-terminal single-nanowire photodetector devices to investigate the photoelectric properties of the hybrid nanostructures. We developed a novel two-step growth process for uniform crystalline PbI2 nanosheets via reactive magnetron deposition of a lead oxide film followed by subsequent iodination to PbI2 on a ZnO NW substrate, and we compared as-grown hybrid nanostructures with ones prepared via thermal evaporation method. ZnO–PbI2 NWs were characterized by scanning and transmission electron microscopy, X-ray diffraction analysis and photoluminescence measurements. By fabricating two-terminal single-nanowire photodetectors of the as-grown ZnO–PbI2 nanostructures, we showed that they exhibit reduced dark current and decreased photoresponse time in comparison to pure ZnO NWs and have responsivity up to 0.6 A/W. Ab initio calculations of the electronic structure of both PbI2 nanosheets and ZnO NWs have been performed, and show potential for photoelectrocatalytic hydrogen production. The obtained results show the benefits of combining layered van der Waals materials with semiconducting NWs to create novel nanostructures with enhanced properties for applications in optoelectronics or X-ray detectors.

Microstructure and phase composition of ZrN/SiNx multilayered coatings formed by reactive magnetron deposition

In the present work, the microstructure and phase composition of multilayered nanoscaled ZrN/SiNx coatings with different thicknesses of individual ZrN and SiNx layers were investigated. The results of transmission electron microscopy (HRTEM) showed that multilayer ZrN/SiNx coatings formed by reactive magnetron deposition are alternating layers of ZrN and SiNx. The X-ray reflectometry (XRR) method made it possible to determine the density, thickness, and surface roughness of individual ZrN and SiNx layers. X-ray diffraction analysis showed that ZrN and SiNx layers have a crystalline and amorphous structure, respectively. The phase composition of mononitride ZrN coatings is characterized by the presence ZrN phase with preferential orientation (111). Phase composition results indicate a change in the preferential orientation from (111) observed for the mononitride ZrN films, to (200) forming in the multilayered ZrN/SiNx coatings.

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.

INFLUENCE OF SUBSTRATE HEATING AND BIAS POTENTIAL ON THE Ti Al C N COATINGS OPTICAL CHARACTERISTICS

Ti–Al–C–N coatings were produced by reactive magnetron deposition at different substrate temperatures Ts (220, 340 and 440 °C) and bias voltages Ubias (–90, –150 and –200 V). Using the energy dispersive X-ray spectroscopy method, it was found that the increase of the bias voltage led to a growth of argon atomic concentration and the (Al + Ti) / (Ti + N) ratio and to a decrease of the trace oxygen concentration in Ti–Al–C–N coatings. The growth of Ts promoted a decrease in the oxygen concentration. By means of scanning electron microscopy, a change in the type of the microstructure (columnar, granular and mixed columnar-granular) of coatings by varying Ts and Ubias was found. Electrophysical measurements showed the change of the film resistivity (1982–3169 μΩ · cm) when the deposition conditions were varied. The solar absorptance αs was varied from 0.24 to 0.54, the emittance ε was varied from 0.33 to 0.52, and the αs / ε ratio was varied from 0.60 to 1.44 by changing Ts and Ubias. The obtained results indicate the opportunity to vary the Ti–Al–C–N films electrophysical and optical characteristics by choosing optimal substrate heating temperature and bias voltage.

Effect of deposition conditions on physical properties of sputtered silicon oxynitride thin films on float glass

AbstractSilicon oxynitride layers have been widely used to tailor the optical performance and mechanical resistance of multilayer optical coatings. The key issue for their reliable large‐scale application on a glass substrate is the effect of technological parameters on their performance. Here we report on the interrelationship between the conditions of the reactive magnetron deposition process and composition, structure and in turn optical and mechanical properties. The process gas composition and pressure level exhibit a strong influence on the film properties, whereas only moderate effect of magnetron power was observed. The O/(O+N) ratio of the films changes from 0.33 to 0.90 and the film density varies between 2.66 g.cm−3 and 1.85 g.cm−3 along with the increase in the process gas pressure from 0.58 Pa to 1.02 Pa. The refractive index shifts between 1.81 and 1.48 and the residual stress of the film varies in the range from compressive (−385 MPa) to tensile (26 MPa). Hardness and reduced modulus follow the same trend and decline with the increase in process pressure from 12.1 GPa to 2.1 GPa and from 120.3 to 31.6 GPa, respectively. The abrasive wear resistance decreases with the nitrogen content in the films.

Role of carbon in the formation of the structure and magnetic properties of Ni@CNx nanoclusters under reactive magnetron deposition

Role of carbon in the formation of the structure and magnetic properties of Ni@CNx nanoclusters under reactive magnetron deposition

Low Pt Content Proton Exchange Membrane Fuel Cell Stack

Pt doped cerium oxide thin films with a nano-porous structure was prepared by reactive rf magnetron deposition on a fuel cell gas diffusion layer [1] coated with nitrogenated amorphous carbon films (CNx) as an interlayer. We show that the structure and morphology of the cerium oxide-CNx composites depend on the oxygen and nitrogen concentration in working gas used for catalyst deposition. Considerable plasma erosion of the carbonaceous interlayer accompanied by the formation of highly porous carbon/cerium oxide bilayer systems is reported. Oxygen plasma etching of the carbon interlayer occurring simultaneously with cerium oxide film growth is considered to be the driving force for the formation of cerium oxide film nanoporosity with large active surface. Thin film techniques permits to grow the catalyst film characterized by highly dispersed platinum [2] showing high hydrogen oxidation activity and stability. These new materials may help to substantially reduce the demand for expensive noble-metals in proton exchange membrane fuel cell (PEMFC) catalytic applications. We prepared 50 cm2 MEAs with 6 μg Pt/cm2 anode and 300 μg Pt/cm2 cathode catalysts. The MEAs activity were measured in 10 cell hydrogen/air water cooled PEMFC stack, developed in our laboratory. Efficiency measurements performed at different pressures, temperatures, and hydrogen flow conditions were compared with performance of standard reference MEAs. We showed that MEAs made by assembling thin film Pt-CeOx/CNx anodes, containing 6 μg Pt per 1 cm2 only, and reference cathodes can be used for fabrication of state of the art low Pt content PEMFC stacks delivering high specific power. It is shown that the almost Pt free anode technology represents promising solution for future fabrication of PEMFC stacks using Pt free cathodes under development. Reference [1] Fiala, R; Figueroba, A; Bruix, A; Vaclavu, M; Rednyk, A; Khalakhan, I; Vorokhta, M; Lavkova, J; Illas, F; Potin, V; Matolinova, I; Neyman, KM; Matolin, V, High efficiency of Pt2+- CeO2 novel thin film catalyst as anode for proton exchange membrane fuel cells, Appl. Catal. B-Environ., 197 : 262–270, 2016. [2] Dvorak, F; Camellone, MF; Tovt, A; Tran, N-D; Negreiros, FR; Vorokhta, M; Skala, T; Matolinova, I; Myslivecek, J; Matolin, V; Fabris, S, Creating single-atom Pt-ceria catalysts by surface step decoration, Nat. Commun., 7 (Feb): Art. No. 10801, 2016.

Effective reactive pulsed magnetron sputtering of aluminium oxide – Properties of films deposited utilizing automated process stabilizer

The formation of dielectric composites on a target surface (target poisoning) reduces the deposition rate of a reactive magnetron deposition process in comparison to the deposition rate of metals. One way of minimizing this reduction is shifting the magnetron operating point from the dielectric to the transient mode. The goal of this paper is to show that a stable process of efficient aluminium oxide deposition can be carried out in a transient mode. An automated stabilizer driven by the electrical parameter of the magnetron power supply was used for process stabilization. The approach of process stabilization in the transient mode resulted in about seven times higher deposition rate of aluminium oxide than that of a standard dielectric mode and only two times lower than the deposition rate of aluminium. The optical properties of the thus obtained aluminium oxide films were studied by means of ellipsometric analysis. The model of film structure, consisting of stoichiometric aluminium oxide, metallic inclusions and voids, was proposed and dispersion characteristics were calculated. The complex refractive index characteristics were similar to those typical of aluminium oxide deposited during a standard pulsed reactive magnetron sputtering process.

(Invited) Plasma Assisted Preparation of Low Pt Content Proton Exchange Membrane Fuel Cell Anode Catalysts

Pt doped cerium oxide thin films with a nano-porous structure was prepared by reactive rf magnetron deposition on a fuel cell gas diffusion layer (GDL) coated with nitrogenated amorphous carbon films (CNx) as an interlayer. We show that the structure and morphology of the cerium oxide-CNx composites depend on the oxygen and nitrogen concentration in working gas used for catalyst deposition. Considerable plasma erosion of the carbonaceous interlayer accompanied by the formation of highly porous carbon/cerium oxide bilayer systems is reported. Oxygen plasma etching of the carbon interlayer occurring simultaneously with cerium oxide film growth is considered to be the driving force for the formation of cerium oxide film nanoporosity with large active surface. Thin film techniques permits to grow the catalyst film characterized by highly dispersed platinum showing high hydrogen oxidation activity and stability. These new materials may help to substantially reduce the demand for expensive noble-metals in proton exchange membrane fuel cell (PEMFC) catalytic applications. We measured Pt-CeOx thin film anode catalyst activity in hydrogen PEMFC and compared it with performance of a standard reference cell. We showed that membrane electrode assembly (MEA) made by assembling Pt-CeOx/CNx anode, containing 2-4 μg per cm2 only, and a reference standard cathode can deliver 1.2 W/cm2 power density.

Phase map, composition and resistivity of reactively magnetron sputtered and annealed Ta–N films

Thin films of tantalum nitride (Ta–N) have been prepared by reactive magnetron deposition under various nitrogen partial pressures and subsequently annealed (Ta = 450–950 °C). The structure, density, composition and electrical resistivity of the prepared films were systematically investigated. A phase map was constructed from the results of structural analysis. With increasing of from 0 to 0.2, a single-phase or two-phase mixture films of tetragonal Ta, Ta2N ( °C), ϵ-TaN ( °C), θ-TaN ( °C) and fcc δ-TaN are sequentially observed. For –0.45, the as grown and annealed films exhibit δ-TaN structure. Amorphous films grown in the –0.75 range crystallize as cubic Ta2N3 upon annealing at °C or as δ-TaN at °C. A cubic Ta2N3 is grown at highest (0.85), which decomposes to δ-TaN at °C. The N / Ta atomic ratio in the film linearly increases for –0.5, ranging from 0 to 2.1, while the mass density monotonically decreases with . Upon annealing, a part of N atoms out-diffuses from the films deposited at . The electrical resistivity strongly depends on both and Ta. However, in the as grown and annealed δ-TaN films the resistivity was of the order of 100–1000 cm. In these films, a correlation between the resistivity and the average number of defects (Ta vacancies and N atom excess) is observed. Finally, the influence of thermally introduced oxygen on the films resistivity has been revealed.

Реактивное магнетронное осаждение оксида индия, легированного оловом, с контролем рабочего давления

Реактивное магнетронное осаждение оксида индия, легированного оловом, с контролем рабочего давления

Magnetron formation of Ni/YSZ anodes of solid oxide fuel cells

Physico-chemical and structural properties of nanocomposite NiO/ZrO2:Y2O3 (NiO/YSZ) films applied using the reactive magnetron deposition technique are studied for application as anodes of solid oxide fuel cells. The effect of oxygen consumption and magnetron power on the discharge parameters is determined to find the optimum conditions of reactive deposition. The conditions for deposition of NiO/YSZ films, under which the deposition rate is maximum (12 μm/h), are found and the volume content of Ni is within the range of 40–50%. Ni-YSZ films reduced in a hydrogen atmosphere at the temperature of 800°C have a nanoporous structure. However, massive nickel agglomerates are formed in the course of reduction on the film surface; their amount grows at an increase in Ni content in the film. Solid oxide fuel cells with YSZ supporting electrolyte and a LaSrMnO3 cathode are manufactured to study electrochemical properties of NiO/YSZ films. It is shown that fuel cells with a nanocomposite NiO/YSZ anode applied using a magnetron sputtering technique have the maximum power density twice higher than in the case of fuel cells with an anode formed using the high-temperature sintering technique owing to a more developed gas-anode-electrolyte three-phase boundary.

A Synthesis of Pure Monolayer VO2 Films with High Visible Transmittance

Thermochromic VO 2 thin film was synthesized on glass slide substrates by reactive RF magnetron deposition (T dep = 450 � C) following annealing (T ann = 400 � C). The method of synthesis results in the formation of preferred orientation vanadium dioxide with acicular nano-structure. The transmittance of monolayer VO 2 thin film reaches to 67% in the visible light region. This study provides a novel method to improve visible transmittance of VO 2 thin films, which boosts their practical applications in smart windows.