Non-reactive RF Magnetron Sputtering Research Articles

Cu 4O3 thin films deposited by non-reactive rf-magnetron sputtering from a copper oxide target

Copper oxide thin films deposited by sputtering are frequently formed by using metal copper targets in reactive atmospheres. In this report, paramelaconite (Cu4O3) thin films were deposited by non-reactive rf magnetron sputtering. The target used for sputtering was a copper oxide disk fabricated by oxidation of metal copper at 1000 °C for 24 h in airatmosphere. X-ray diffraction (XRD) results showed that the copper oxide target was mainly composed of cupric oxide (CuO) and cuprous oxide (Cu2O) crystals. Raman analyses suggested that the surface of the copper oxide disk is composed by a (CuO) layer. XRD measurements performed to the copper oxide thin films deposited by non-reactive rf magnetron sputtering showed that the film is composed of (Cu4O3) crystals. However,Raman measurements indicated that the Cu4O3 thin films are also composed by amorphous CuO and Cu2O.

Morphology and Optical Properties of Thin Cd3As2 Films of a Dirac Semimetal Compound

Using atomic-force microscopy (AFM) and wide-band (0.02–8.5 eV) spectroscopic ellipsometry techniques, we investigated the morphology and optical properties of Cd3As2 films grown by non-reactive RF magnetron sputtering on two types of oriented crystalline substrates (100)p-Si and (001) α-Al2O3. The AFM study revealed the grainy morphology of the films due to island incorporation during the film growth. The complex dielectric function spectra of the annealed Cd3As2/Al2O3 films manifest pronounced interband optical transitions at 1.2 and 3.0 eV, in excellent agreement with the theoretical calculations for the body centered tetragonal Cd3As2 crystal structure. We discovered that due to electronic excitations to the Cd(s) conical bands, the low-energy absorption edge of the annealed Cd3As2 films reveals a linear dependence. We found that for the annealed Cd3As2 films, the Cd(s) conical node may be shifted in energy by about 0.08–0.18 eV above the heavy-flat As(p) valence band, determining the optical gap value. The as-grown Cd3As2 films exhibit the pronounced changes of the electronic band structure due to the doping effect associated with Cd non-stoichiometry, where fine-tuning of the Cd concentration may result in the gapless electronic band structure of Dirac semimetals.

Electrical insulation performance of aluminum oxide layers on metallic substrates – HiPIMS compared to RF-MS

In this evaluation, aluminum oxide layers with thicknesses in the range of 300 nm to 4000 nm are investigated for their electrical insulation capability by measuring the resistance between the substrate and a subsequent conductive layer. The deposition was carried out in a non-reactive RF magnetron sputtering process and in a reactive HiPIMS process, respectively. The substrate materials tested are steel 1.3505 (100Cr6), titanium alloy 3.7164 (Ti6Al4V) and aluminum alloy 3.1645 (AlCuMgPb) with both turned and polished surfaces.Besides resistance measurements, the layers were investigated by SEM and characterized by EDX. During the HiPIMS deposition, the value of the electrical current over the time of one pulse was measured additionally.The comparison of the resistance values showed strong dependencies between the electrical insulation and the substrate materials used, as well as their surface microstructure. Moreover, a deviating insulation performance for the layers deposited by HiPIMS was identified. From the results, a correlation of substrate material, surface microstructure and the corresponding deposition technology is deduced.

Comparative studies on the properties of magnetron sputtered transparent conductive oxide thin films for the application in solar cell

Transparent conductive ZnO:Al and ZnO:Ga ultrathin films have been developed on glass substrate at room temperature by non-reactive RF magnetron sputtering using sintered ceramic disc of ZnO:Al target (ZnO 98%, Al 2%), and ZnO:Ga target (ZnO 97%, Ga 3%). The thin films (90–250 nm) of ZnO:Al and ZnO:Ga show low resistivity of 8.6 × 10−5 and 4.5 × 10− 4 Ω cm, respectively. The ZnO:Al thin film exhibits highest transparency of 92%, haze factor of 54% in the visible region and electrical mobility of 12 cm2/V s. Similar kinds of results (highest electrical mobility is 10 cm2/V s, haze factor varies from 28 to 44%) are observed for ZnO:Ga thin films. The moderate improvement on thickness-dependent electrical mobility for very thin ZnO:Ga and ZnO:Al films are due to improved crystallinity, increased crystallite sizes but negative effect comes from grain boundary scattering and higher surface roughness. X-ray diffraction spectra reveal polycrystalline nature of ZnO:Ga and ZnO:Al thin films with grain size 22 and 19 nm, respectively. Variation of thickness and composition-dependent structural, morphological and optical haze properties of Al- and Ga-doped ZnO thin films have been compared with that of conventional ITO and SnO2:F thin films.

Study of ZnS/CdS structures for solar cells applications

ZnS/CdS bilayers were prepared by non-reactive RF magnetron sputtering. The bilayers were post-annealed from 100°C to 500°C. The films were characterized by X-ray diffraction analysis, atomic force microscopy, optical spectroscopy, and photoluminescence spectra. It was found that changing the annealing temperature for the multilayers ZnS/CdS is possible to promote the formation of ZnxCd1-xS thin films. For CdTe/CdS solar cells this is an interesting route to improve the window layer.

Room Temperature Deposited Transparent Conducting InZnO:Ga thin films by Non-Reactive RF-Magnetron Sputtering

Transparent-conducting InZnO:Ga (IZO:Ga) thin films have been developed on glass substrate at room temperature (300K) by nonreactive RF-Magnetron sputtering using sintered ceramic disc of InZnO:Ga target (In-10 wt%, Ga -3wt% and Zn -87wt%). The novelty of very thin IZO:Ga films are low resistivity (1.5×10−3Ω.cm) and low sheet resistance (20 Ω/□) with average optical transmittance 86%, large Haze factor (>70%) and high figure of merit value (1.1×1018) respectively. RF-sputtered IZO:Ga films shows amorphous nature, smooth and crack-free surface morphology and topography with predominant metallic phase. Heat treated samples becomes crystalline, topography becomes more aligned (U-type) and surface roughness increases.

RETRACTED ARTICLE: Growth and Characterization of Tungsten Oxide Thin Films using the Reactive Magnetron Sputtering System

WO3 thin film is one of the most important and applied metal oxide semiconductors that have attracted the scientist’s attention in recent decades. WO3 thin films by two different methods: reactive and non-reactive RF magnetron sputtering deposited on soda lime glass. The effect of presence and absence of oxygen gas in system and RF power on structural, morphological and optical properties of thin films were investigated. The XRD analysis of the films shows the amorphous structure. Spectrophotometer analysis and calculation show that the optical properties of reactive sputtered layers were better than the non-reactive sputtered thin films. By changing deposition parameters, over 70 % transmission achieved for WO3 films. The results showed that reactive sputtering method improved the optical properties of layers and increased band gap up to 3.49 eV and on the other hand reduced roughness of thin films. On the whole, presence of oxygen in the chamber during sputtering improved properties of WO3 thin films.

Synthesis and characterization of photochromic Ag-embedded TiO2 nanocomposite thin films by non-reactive RF-magnetron sputter deposition

Ag-embedded TiO2 nanocomposite thin film with reversible photochromic properties were prepared by layer-by-layer non-reactive RF-magnetron sputtering. Films were produced in Ar/O2 and pure Ar atmospheres. In the oxidizing regime, a diffusion of Ag from the film volume to the outer film surface was observed. Therefore, pure Ar plasma was applied in the deposition of TiO2. The electronic and optical properties of the TiO2 film were almost not affected by the presence of oxygen. Transmission electron microscopy (TEM) and reflection mode X-ray absorption spectroscopy (XAS) were performed to study the morphology, crystal structure and chemical state of the embedded Ag nanoparticles before and after the annealing step. Annealing of the film led to the crystallization of the TiO2 matrix. Moreover, the Ag nanoparticles in the film underwent Ostwald ripening leading to particle agglomerate. No oxidation of the embedded Ag during the sputter deposition and subsequent annealing process was found as confirmed by XAS measurements. The non-reactive RF-magnetron method is believed to avoid the energetic oxygen ions attack to Ag during the deposition of Ag-embedded TiO2 nanocomposite and thus the films are expected to have better optical properties and long-term stability.

Laser micro-structuring of magnetron-sputtered SnOx thin films as anode material for lithium ion batteries

SnOx electrode thin films for lithium ion batteries were deposited by reactive and non-reactive rf magnetron sputtering of a SnO2 target in an argon–oxygen atmosphere. Amorphous and nano-crystalline SnOx films could be synthesized, with regard to the O2:Ar volume ratio in the sputter gas which was adjusted to 0, 3.5 or 10%. Laser micro-structuring using a KrF excimer laser operating at a wavelength of λ = 248 nm was applied to create free-standing microstructures. Thus, the active surface of the anode material was significantly increased. Furthermore, it was expected that the large volume changes during electrochemical cycling of SnOx could be better compensated by a microstructured surface. The laser parameters were optimized in a way which leads to structures without any defects and little debris. Depending on the laser fluence and pulse number, free-standing conical structures could be formed with a horizontal spacing of <0.5 μm up to 2 μm. The structured and unstructured thin films were cycled in a battery tester against metallic lithium. The structured SnOx thin films exhibited significantly better battery performance with respect to cycling stability.

Microstructural and magnetic properties of thick (≥10 μm) magnetron sputtered barium ferrite films

This work focuses on the properties of 10–15 μm thick barium M-type hexaferrite (BaFe 12O 19 or BaM) films deposited by non-reactive RF magnetron sputtering on alumina substrates. High deposition rates were achieved through deposition at room temperature and operation at an RF power of 100 W. By varying sputtering gas pressure, the dc magnetic properties were correlated with structural, morphological and compositional properties obtained by X-ray diffraction (XRD), atomic force microscopy (AFM) and Rutherford backscattering spectrometry (RBS), respectively. A deposition pressure of P=3 Pa enables one to reach the best compromise between high deposition rate (0.75 μm/h) and adequate crystallographic, stoichiometric and magnetostatic properties. Finally the gyromagnetic properties at high frequency were assessed through the characterization of coplanar isolator up to 60 GHz. As such, hexaferrite films prepared using this technique may offer opportunities for the next generation of self-biased planar microwave devices.

Growth kinetics and properties of nanostructured hafnium diboride films

The composition, structure, substructure, and physicomechanical properties of hafnium diboride films deposited by nonreactive rf magnetron sputtering are studied by X-ray diffraction (including photographic recording) and electron microscopy. The results obtained are analyzed, and the film growth kinetics is revealed.

Structured ZnO-based contacts deposited by non-reactive rf magnetron sputtering on ultra-thin SiO 2/Si through a stencil mask

In this paper, we study the localized deposition of ZnO micro and nanostructures deposited by non-reactive rf-magnetron sputtering through a stencil mask on ultra-thin (10 nm) SiO 2 layers containing a single plane of silicon nanocrystals (NCs), synthetized by ultra-low energy ion implantation followed by thermal annealing. The localized ZnO-deposited areas are reproducing the exact stencil mask patterns. A resistivity of around 5 × 10 − 3 Ω cm is measured on ZnO layer. The as-deposited ZnO material is 97% transparent above the wavelength at 400 nm. ZnO nanostructures can thus be used as transparent electrodes for Si NCs embedded in the gate-oxide of MOS devices.

Conductivity and the Hall coefficient of nanostructured titanium nitride films

The conductivity and the Hall coefficient of nanostructured TiN films synthesized by nonreactive RF magnetron sputtering have been experimentally studied. The mechanism of conductivity and the role of grain size are discussed.

Characaterization of WMeC (MeFe, Co) films and their structural behaviour with temperature

Metastable WMeC (MeFe, Co) films were obtained by non-reactive RF magnetron sputtering. Their initial state and thermal stability were studied by means of electron probe microanalysis, secondary ion mass spectrometry and X-ray diffraction. The results show that the structure at room temperature depends on the percentage of iron and cobalt in the films, varying from β-WC 1− x to amorphous with the increasing content of these elements. The structure of the crystalline films changes with temperature from β-WC 1− x to WC and W 2C. The crystallization mechanism of the amorphous films is characterized by the formation of carbon-deficient phases, such as W 2C or M 6C.