Cathodic Magnetron Sputtering Research Articles

Optical spectroscopy on processing plasmas: cathode magnetron sputtering and flowing post-discharges for elastomer activation and medical sterilization

This article is focused on emission spectroscopy whose the main interest is in a non intrusive diagnostics, allowing a control and a piloting of the surface treatment process. To analyse a given plasma process, the emission spectroscopy must be coupled to the plasma kinetic equations. These mechanisms are described for a PVD process with a RF-activated magnetron DC cathode where it is shown how to follow the metal ionization degree with the example of Cu sputtering. In a second part of the article, it is shown how to measure the absolute densities of N- and O-atoms by NO titration in flowing N2 and O2 post-discharges, with applications to the activation of elastomers and to the sterilization of oral bacteria. In a chosen N2–O2 flowing microwave post-discharge, it has been obtained a decrease of 12 log (when 6 log is necessary for sterilization) for E. coli bacteria after a treatment time of 15 min.

Fullerene-like B [sbnd]C [sbnd]N thin films: a computational and experimental study

Ab initio calculations show that the energy cost for incorporating lattice defects such as pentagons and heptagons is significantly reduced for BCN compared to BN, thus promoting bending of basal planes in these compounds. Boron–carbon–nitride (B C N) thin films with a fullerene-like (FL) microstructure were then deposited by dual cathode magnetron sputtering from C and B 4C targets. Up to 1 μm thick films were grown at a total gas pressure of 3 mTorr (0.4 Pa) in varying Ar/N 2 ratios, and substrate temperatures between 225 and 350 °C. Compositional and microstructural studies were performed using RBS, SEM and HREM, respectively. Depending on the deposition condition, ternary B x C y N z films with fullerene-like microstructure could be prepared in agreement with the calculations within the composition range 0 ≤ x ≤ 53, 15 ≤ y ≤ 62, and 24 ≤ z ≤ 50 at.%. Fullerene-like structures also tend to form at lower temperatures in the case of BCN compared to CN. Nanoindentation measurements show that all B x C y N z films exhibited a highly elastic response independent of elemental composition. In addition, the calculations suggest a driving force for C and BN phase separation.

Improved film deposition of carbon and carbon nitride materials on patterned substrates by ionized magnetron sputtering

This work is mainly devoted to the study of thin film deposition by ionized magnetron sputtering (IMS). This process is based on a standard magnetron cathode sputtering deposition assisted by an induced r.f. discharge generated by an r.f. powered coil (antenna), placed between the substrate and the cathode (target). A very different deposition behavior is obtained compared to a classical magnetron process. We have used IMS for carbon and carbon nitride deposition in order to improve the relatively low deposition rate obtained by magnetron sputtering. In this paper, the ability of IMS to fill holes and trenches of micronic and sub-micronic size with amorphous carbon and carbon nitride films is particularly studied. Several patterns realized onto silicon substrates have been used: holes and trenches of different width. In particular, the influence of the substrate bias voltage is studied by determining the deposition rate at the top and the bottom of the holes and trenches. Moreover, the investigation by scanning electron microscopy of the film morphology has revealed the growth of original structures.

Improved film deposition of carbon and carbon nitride materials on patterned substrates by ionized magnetron sputtering

This work is mainly devoted to the study of thin film deposition by ionized magnetron sputtering (IMS). This process is based on a standard magnetron cathode sputtering deposition assisted by an induced r.f. discharge generated by an r.f. powered coil (antenna), placed between the substrate and the cathode (target). A very different deposition behavior is obtained compared to a classical magnetron process. We have used IMS for carbon and carbon nitride deposition in order to improve the relatively low deposition rate obtained by magnetron sputtering. In this paper, the ability of IMS to fill holes and trenches of micronic and sub-micronic size with amorphous carbon and carbon nitride films is particularly studied. Several patterns realized onto silicon substrates have been used: holes and trenches of different width. In particular, the influence of the substrate bias voltage is studied by determining the deposition rate at the top and the bottom of the holes and trenches. Moreover, the investigation by scanning electron microscopy of the film morphology has revealed the growth of original structures.

Ion bombardment: a means to improve the properties of TiN/AlN multilayered coatings

Various multilayered systems were realised by reactive magnetron cathodic sputtering with DC polarisation for TiN layers and RF polarisation for AlN layers. Different types of ion bombardment were used during coating elaboration. The first type (I) is ion bombardment applied after sputtering of each layer in the multilayered system. The second (type II) is ion bombardment applied during deposition. The third (type III) is ion bombardment applied during deposition and after sputtering of each layer. All multilayered coatings show a periodic structure with more or less good-quality interfaces, depending on whether ion bombardment was applied or not. The type of ion bombardment influences the properties of these multilayered systems, such as the nanohardness and the elastic recovery.

Super-smooth indium–tin oxide thin films by negative sputter ion beam technology

An ionized physical vapor deposition, negative sputter ion beam (NSIB) technology, is described for the deposition of super-smooth indium–tin oxide (ITO) thin films with highly transparent and conductive properties at near-room temperature deposition. A negatively charged sputter ion beam is produced by retrofitting an ITO magnetron sputtering cathode with a cesium vapor injector capable of releasing controlled amounts of cesium vapor into the plasma during deposition. Using this highly energetic deposition process, ITO thin films have been obtained at near-room temperature (less than 50 °C) with super-smooth surface (<1 nm rms), resistivity of 4×10−4 Ω cm, and transmittance higher than 85% (at wavelength 550 nm) on polycarbonate substrates.

Depth profiles study of n(TiN+AlN) bilayers systems by GDOES and RBS techniques

Some n(TiN+AlN) bilayers systems with n=1 and n=2 are realised by reactive magnetron cathodic sputtering. Different layers and interfacial zones are studied by glow discharge optical emission spectroscopy (GDOES) and Rutherford backscattering spectroscopy (RBS). With GDOES analysis, it is possible to check the bilayers number in each system, the total thickness of coating and the bilayer's thickness. It is also possible to compare the thickness and the roughness of interfacial zone. The higher the slope is, the less rough is the interfacial zone. A great quantity of oxygen is present, mainly in interfacial zones, when any ion bombardment is not applied. This oxygen is nearly completely eliminated, when an ion bombardment is applied during the coating's elaboration. This contamination is confirmed by the stoichiometry's determination of different layers of bilayers systems, with some RBS analyses. These RBS analyses show the interfacial roughness owing to the disagreement between the experimental points and the simulation points. To obtain a good fitting, we should simulate, in case of (TiN+AlN) systems, an additional layer, which plays the role of interfacial layer. When an ion bombardment is applied during sputtering deposition, the interfaces are well-defined and without oxygen. For 2(TiN+AlN) systems, the interfaces also appear very rough without ion bombardment.

Properties of Ti1−xSixNy films deposited by concurrent cathodic arc evaporation and magnetron sputtering

A new technique is described in the synthesis of thin films of Ti1−xSixNy based on the concurrent reactive deposition of Ti produced by a cathodic arc source and Si produced by a d.c. magnetron sputter source. The technique permits the controllable doping of TiN with silicon over the range of 1–16 at.%. The films were found to have a microhardness of 70 GPa with a compressive stress of 5.5 GPa when deposited with a magnetron power of 220 W and a bias voltage of −150 V, and a maximum hardness of 58 GPa and stress values of approximately 3.3 GPa when deposited using 280 W magnetron power and −50 V bias. The hardness and stress of TiN was found to be 26 and 3.5 GPa, respectively, when deposited in the absence of the magnetron.

Rapid chemical and structural characterization of metastable thin‐film libraries by a combination of electron probe microanalysis and scanning x‐ray diffraction

AbstractThe increasing complexity of modern coatings leads to the demand for a cost‐effective tool for the development of new products in the advanced materials industry. One possible approach to this question is the adaptation of combinatorial methods to the specific requirements of the coatings industry.In this paper, the deposition and characterization of two‐dimensionally laterally graded (Ti,Al,Si)N hard coatings deposited by a triple cathode magnetron sputtering arrangement is presented. The three cathodes, equipped with aluminium, silicon and titanium targets, respectively, were adjusted at a low angle to the surface. Additionally, a system of apertures was mounted between the cathodes. The relation between composition and structure of the resulting materials library was investigated by a combination of electron probe microanalysis (EPMA) and scanning x‐ray diffraction. Copyright © 2002 John Wiley & Sons, Ltd.

Chromium-based thin sputtered composite coatings for solar thermal collectors

One of the fundamental components of a solar thermal collector is the absorber surface that should be spectrally selective for solar radiation. Efficient solar photothermal conversion benefits from spectrally selective absorber surfaces. Most solar selective coatings use metal-dielectric composites, known as cermets, as the absorber of solar energy. In this study we will present a numerical model that allow us to correlate the selectivity of the produced absorbers to the collector efficiency. The cathodic magnetron sputtering being a promising method to produce thin solar selective films, a study of some cermet Cr–Cr 2O 3–CrO 3 coatings obtained by this technique in reactive atmosphere and using a DC power unit will be presented. The multilayered composites produced were based in metallic chromium in a matrix of a chromium oxide with a gradient in oxygen composition. The selective graded films were produced by a reactive DC magnetron sputtering of pure chromium target in a plasma of argon–oxygen at different sputtering pressures and substrate temperatures. The microstructure, surface roughness, crystallographic phases, composition and chemical analysis by X-ray photoelectron spectroscopy and reflectivity spectra in vis-NIR were analysed.

Characterisation studies of the pulsed dual cathode magnetron sputtering process for oxide films

Pulsed magnetron sputtering has become the leading industrial production process for large area thin film deposition due to its versatility, low environmental impact and ability to provide uniform coatings across large substrate areas. Such applications commonly employ oxides, including silica (SiO 2), alumna (Al 2O 3) and titania (TiO 2). Although all of these materials can be produced by reactive DC-magnetron sputtering, until recently the deposition process was highly problematic. The industrial exploitation of the pulsing process is impeded by the fact that, during long-term deposition runs, eventually all surfaces will be covered with the insulator. Once the chamber and anode are covered with insulating material, there can be no average (DC) current flowing to the power supply leads. Moreover, if the anode/chamber becomes covered with the dielectric film it will cease to operate as an effective ground (anode). A more viable approach is to use two magnetrons in a dual bipolar arrangement (dual cathode). In this arrangement each magnetron acts alternatively as an anode and a cathode. The broad aim of this study is to investigate the inter-relationship between ‘global’ parameters, pulse parameters, plasma parameters and in particular, film properties in relation to the dual cathode system. The spatial distribution of measured parameters will be considered. This paper describes the production of Al 2O 3 films by dual cathode unbalanced reactive magnetron sputtering, in particular, the effects of spatial distribution and pulse frequency on coating properties. In general, it was observed that, once hard arcs have been removed, all coating structures, coating surfaces and hardness show little variation. However, more variation was observed in critical loads during scratch adhesion testing for coatings deposited at different pulse frequencies.

Structure and tribological properties of MoS x coatings prepared by bipolar DC magnetron sputtering

MoS x coatings were prepared by bipolar pulse DC (balanced and unbalanced) magnetron-sputtering systems. Deposition parameters, cathode current density, argon pressure, bias voltage and magnetron sputtering conditions, were varied in order to obtain low friction and wear-resistant coatings. Composition and surface morphology were determined by energy dispersive X-rays and scanning electron microscopy, while the structure was investigated by X-ray diffraction. The friction and wear properties were investigated by fretting tests in ambient air of <10% and 50% relative humidity. On proper selection of the argon pressure and the cathode current density, MoS x coatings characterised by a strong (002) basal plane orientation parallel to the substrate were obtained in a reproducible way. Such coatings deposited under optimised conditions exhibit very good lubricity and high wear-resistance, even in ambient air with a relative humidity of 50%. Conversely, when deposition parameters such as higher argon pressure and larger cathode current density result in the deposition of a MoS x coatings with a needle-like structure and preferential (100) and (110) plane orientations, a lower wear resistance is achieved especially in air of 50% relative humidity. Ion bombardment, achieved by applying a negative voltage bias or unbalanced sputtering conditions, improves the friction and wear performance. Conversely, a positive bias voltage deteriorates the tribological performance of the coatings. Experimental data on the friction and sliding wear resistance for MoS x coatings indicate that the best tribological properties are obtained with low sulfur and featureless MoS x coatings.

Macroparticle induced corrosion for arc bond sputtering CrN/Nbn superlattice coatings

Transition metal nitride (TMxNy ) coatings prepared by physical vapor deposition (PVD) techniques have proven to be highly wear and corrosion resistant, thanks to the excellent combination of high hardness, electrical and thermal conductivity, and electrochemical nobility. Although a mere monolayer of binary TiNor CrN could have remarkable effect on increasing a machining tool's life in the early days, more complex ternary or higher coatings, with a functional base layer, or consisting of multiple layers, have been explored subsequently for enhanced performances in wear or corrosion. As for the coating techniques, while the traditionally classified evaporation deposition, sputter deposition, and ion plating (using relatively low keV ion beams to assist vapor deposition) have all been enjoying some success in achieving particular coating properties, recent years have seen the emergence of a particular promising sputter deposition technique, namely the arc bond sputtering (ABSTM), which combines the cathodic arc evaporation and unbalanced magnetron sputtering (UBM) in one process [1].

Computer simulation of gas rarefaction effects and film deposition characteristics in a magnetron sputtering apparatus

Ar gas is known to be rarefied in front of a magnetron sputtering cathode due to the collisional heating by energetic sputtered atoms. The effects of the Ar rarefaction in a magnetron sputtering apparatus used for Ti-film deposition were investigated using the direct simulation Monte Carlo (DSMC) method which is capable of taking gas rarefaction effects into account. The calculated film deposition rate on a substrate and the film coverage in a small hole were larger than those calculated by the conventional simulation where the gas rarefaction is not included. This shows that the gas rarefaction improves both the film deposition rate and the film coverage.

Magnetron sputtering cathode with confined magnetic flux

In a planar magnetron cathode, a disk target shows an erosion ring at the central region of the target. It was found that the grounded permalloy sheet which covered the outer surface of the magnetron cathode confined the magnetic leakage flux and enhanced the transverse magnetic field at the outer region of the target. The additional erosion ring was observed at the outer region. The total amount of the sputtered substance increased by 4 times. The grounded permalloy sheet will provide a compact magnetron cathode with a controlled erosion pattern.

Sliding wear behavior of polycrystalline TiN/CrN multilayers against an alumina ball

Sliding wear experiments were conducted using a ball-on-disc rotating friction apparatus to evaluate the wear behavior and properties for TiN, CrN and TiN/CrN multilayers with different modulation periods deposited on WC/Co cemented substrates with reactive magnetron cathodic sputtering. TiN showed the higher coefficient of friction of 0.9 and the higher wear rate due to the larger debris as abrasive remained on wear scar. It was found that the coefficient of friction of TiN/CrN multilayers against the alumina ball ranged from 0.3 to 0.5. TiN/CrN multilayer at Λ of 21 nm, possessing the maximum hardness enhancement, showed the smallest friction coefficient value of 0.3. The lower coefficient of friction of TiN/CrN multilayers corresponds to the enhancement of hardness, the promotion of the formation of the dense Cr 2O 3, and CrO 3 oxide layer, and the exclusion mechanism of debris from the wear scar. The wear volume of TiN/CrN multilayers was decreased with one digit in comparison with that of TiN single layer coatings. TiN/CrN multilayer technique, by enhancing the hardness, promoted the formation of an oxide layer on the wear scar. The dense Cr 2O 3 and CrO 3 oxide layers help to build additional protective films on the worn surface, induce a lower coefficient of friction and will contribute to the decrease of wear loss for TiN/CrN multilayers.

Growth of CN x/BN:C multilayer films by magnetron sputtering

Symmetric CN x /BN:C multilayer thin films, with nominal compositional modulation periods of Λ=2.5, 5, and 9 nm were deposited by unbalanced dual cathode magnetron sputtering from C (graphite) and B 4C targets in an Ar/N 2 (60/40) discharge. The multilayers and single-layer of the constituent CN x and BN:C compounds were grown to a total thickness of 0.5 μm onto Si(001) substrates held at 225°C and a negative floating potential of ∼30 V ( E i ≈24 eV). Layer characterizations were performed by TEM, X-ray reflectivity, RBS, and nanoindentation measurements. Results show that CN 0.33 and BN:C (35, 50, and 15 at.% of B, N, and C, respectively) layers were prepared at the above conditions. It is suggested that all films exhibit a three-dimensional interlocked structure with a cylindrical texture in the film growth direction. The structure was continuous over relatively well defined and smooth CN x /BN:C interfaces. All coatings exhibit extreme elasticity with elastic recoveries as high as 85–90% (10 mN maximum load) attributed to the observed structure. However, the multilayers were stiffer and more elastic compared to that of the single-layers and thus shows promise for improved protective properties.

Investigation of The Oxidation Behaviour of A TiAlCrYN Pvd Hard Coating

AbstractFor dry high speed cutting the oxidation resistance of the protective hard coating of the cutting tool surface is very important. Therefore the effects of heat treatment on a TiAlN based hard coating deposited by the combined cathodic arc unbalanced magnetron sputtering technique have been studied using cross sectional transmission electron microscopy (XTEM) and energy dispersive X-ray analysis (EDX). The combination of these analytical techniques revealed the diffusion paths and preferences in diffusion of various coating and substrate elements in a physical vapour deposited (PVD) type coating after heat treatment. The structure comprises a ~2 µm thick TiAlCrYN coating on top of a 0.25 µm thick TiAlCrN base layer deposited on a stainless steel substrate. In the as-deposited sample Y was distributed in a fine layered structure (1.7 nm) throughout the coating. The coating was heat treated at temperatures between 600 °C and 900 °C in air for 10 hrs duration. With increasing temperature the microstructure changed gradually from interrupted columnar growth to a fully columnar structure at 900 °C as observed with XTEM. EDX analysis after heat treatment at 700 °C showed the presence of substrate elements Fe and Cr mainly at column boundaries in the base layer. In contrast no evidence of substrate elements could be observed in the TiAlCrYN coating, thus showing a sharp change in elemental composition concerning Cr and Fe between base layer and coating. This indicates that Y segregation in the TiAlCrYN coating along column boundaries inhibited column boundary diffusion of the substrate elements Cr and Fe. Energy dispersive X-ray distribution maps recorded after 800 °C annealing showed distinct segregation of Y along the column boundaries. The substrate elements, Fe and Cr, were observed through the coating along column boundaries up to 0.95 µm from the base layer/coating interface. After heat treatment at 900 °C the substrate elements had diffused from the substrate/coating interface to the coating surface. Y out-diffused, too and was concentrated adjacent to TiO2 crystals in the oxide layer.

変形磁界型高周波マグネトロンスパッタ法によるＮｉ薄膜の堆積速度

In order to obtain high deposition rate of Ni films, we have developed a modified magnetron sputtering cathode configuration with a ferromagnetic Ni target of 100 mm in diameter and 5 mm in thickness. The plasma confinement could be enhanced by providing four special permanent magnets around outside the cathode. Nickel films were prepared at the rf power of 100 to 200 W and the argon gas pressure of 6.7×10-1 to 8.1×10-2 Pa. The deposition rate was 14 nm/min, four times as large as that of a conventional magnetron sputtering at an rf power of 100 W and an argon gas pressure of 6.7×10-1Pa.

Growth of high mobility GaN by ammonia-molecular beam epitaxy

The growth of high electron mobility GaN on (0001) sapphire by ammonia molecular beam epitaxy is reported. A buffer layer of AlN &amp;lt;300 Å is initially deposited by magnetron sputter epitaxy, a technique where the aluminum source is a planar dc magnetron sputter cathode and ammonia is used for the nitrogen source. The GaN epilayer is deposited using a conventional K cell for the gallium source and ammonia for the nitrogen source. The layers were doped using silane. Measured room temperature electron mobilities of 560 cm2/V s were observed for layers with carrier densities of ∼1.5×1017 cm−3. The 4 K photoluminescence spectrum showed a very strong donor bound exciton at 3.48 eV with a full width at half maximum (FWHM) of 4.9 meV. X-ray diffraction studies showed the layers to have good crystallinity with FWHM of the ω–2θ and ω scans as low as 13.7 and 210 arcsec, respectively.