Papers by Keyword: Magnetron Sputtering

Abstract: Heterostructures are important for various electrical, optical, and magneto-transport applications. In the present work, MoS₂/ZnO heterostructures are successfully grown by magnetron sputtering followed by annealing of ZnO thin films. After annealing, ZnO is again coated with Mo by using the same technique. ZnO-Mo stack is further sulfurized to convert Mo into MoS₂. X-ray diffraction (XRD) showed the structural analysis of ZnO, MoS_2, and MoS₂/ZnO heterostructures with polycrystalline nature. Scanning electron microscopy (SEM) also supports the granular morphology of ZnO, MoS_2, and MoS₂/ZnO films. Energy dispersive X-ray analysis (EDX) confirms the presence of necessary elements i.e., Zn, Mo, S, O, and Si. Further, the impact of the magnetic field on the current-voltage (I-V) behavior of MoS₂/ZnO heterostructures, reveals insights into their magneto-resistive capabilities.

Abstract: This study considers the growth characteristics of nickel oxide NiO films using DC magnetron sputtering. The hysteresis transition process between sputtering from poisoned and clean Ni target as a function of discharge power was determined. The structure, atomic composition, and optical and electrical properties of NiO films for two modes of sputtering (with low and high discharge power, respectively) have been investigated. It is demonstrated that sputtering parameters have a fundamental effect on both the formation of structure and atomic composition and on the trend of their modification using temperature annealing. The results obtained for each of the sputtering modes can be applied to the development of devices based on catalytic reactions as well as on their semiconductor properties.

Abstract: Magnetron sputtering was utilised to deposit submicron-sized speckle patterns for microscale digital image correlation (DIC) of 18Ni-300 maraging steel. A Taguchi orthogonal array consisting of four configurations was used to investigate the influence of magnetron sputtering parameters (i.e. sputter current, sputter duration, and chamber pressure during sputtering) on the resultant speckle characteristics. Increasing the sputter current resulted in larger-sized speckles, while increasing the sputter duration resulted in larger-sized speckles at expenses size uniformity of speckles. A higher chamber pressure retards the transport of speckles resulting either in low deposition rate or much less uniform sizes of speckles. Among the configurations studied, configuration I (75 mA, 240 s, 3 Pa) produced speckle patterns that were most suitable for microscale DIC as its speckles were adequately smaller and more uniform in size. In-situ tensile test with DIC strain distribution mapping on sample deposited with speckle pattern configuration I shows a strain resolution of about 71 nm, and slip bands with widths measured between 240 to 400 nm, indicating the speckle pattern was suitable, enabling further study on deformation mechanism.

Abstract: Since their early investigations, TiN coatings have sparked considerable interest because of their remarkable mechanical properties, especially their prominent hardness (30–60 GPa) and oxidation resistance. They are mainly used to harden and protect cutting or sliding tools and occasionally for decoration. Small quantities of different ligands, including Ni, Cu, or Co, are added to improve the smooth performance of cutting tools. These alloying elements lead to the formation of nanocomposites, potentially altering their mechanical characteristics and imparting notable flexibility. In this context, this study focuses on the production of pure TiN and Cu-doped TiN thin films. Magnetron sputtering was used as a deposition technique, simultaneously sputtering Ti and Cu-targets, both with high purity (99.99%), and in a gas mixture of Ar and N₂. X-ray diffraction, SEM, profilometry, nanohardness, and scratch test analyses were employed to characterize the TiN and TiN/Cu films. The results reveal that 3–4% of Cu content led to a slight decrease in hardness, while surface adhesion increased with the addition of copper. Furthermore, the elasticity of the doped films improved the strength and wear resistance of coatings with Cu compared to TiN films without added Cu.

Abstract: Ultra-high Molecular Weight Polyethylene (UHMWPE) is a highly versatile polymer known for its exceptional mechanical properties, however, its limited life as an implant material for Total Joint Replacement (TJR) necessitates surface modification to extend its lifespan. This study aims to enhance the surface properties of UHMWPE through application of ceramic coatings. Magnetron sputtering method was used to deposit thin film of white Titania (TiO₂) on the material’s surface. To evaluate the surface characteristics, such as surface roughness, uniformity and structure, coated and uncoated samples were analyzed through Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and X-ray Diffraction Analysis (XRD). The material performance in relation to biological context was investigated through Contact Angle measurement. A comparative analysis of coated and uncoated samples was then performed. The coated samples showed better wettability compared to uncoated sample. This fact highlights the hydrophilic nature of film. The results of the coated UHMWPE suggest that this surface modification technique could significantly extend the lifespan of UHMWPE implants in TJR, potentially addressing the current limitations associated with their longevity.

Abstract: This work investigates the properties of copper thin films deposited by magnetron sputtering. The substrate is biased by a negative voltage (V_s), which controls the energy ions bombardment during the deposition of the thin films. In order to focus solely on the ions energy contribution, the power supply was fixed and the working pressure was selected at 5 Pa. This ensures energetic sputtered particles completely thermalized, by a sufficient number of collisions with the Argon gas. X-ray diffraction analysis revealed that substrate voltage V_s affects essentially the structure and size of the formed crystallites. The preferred orientation (111) and the larger crystallite size (30 nm) were achieved at V_s = - 60 V. The Cu (111)/(200) peak intensity ratio is maximal (12.55) at - 60 V, corresponding to the lowest resistivity value (6.33 mW.cm). Optimum corrosion resistance of the deposited thin film was achieved at -60 V. At high crystallite sizes, nanoindentation analysis showed a thin film that is more elastic (133 GPa) and less hard (1.96 GPa).

Abstract: Tungsten (W) reinforced diamond-like carbon (DLC) nanocomposite thin films were deposited on silicon substrates by magnetron sputtering in a CH₄/Ar discharge. The W content of the films was varied by varying the W target power (20, 40, 60, 80, and 100 W). The evolution of the W-DLC nanocomposites was studied by high-resolution transmission electron microscopy, X-ray energy dispersive spectroscopy, X-ray photoelectron spectroscopy, 3D optical profilometry and Raman spectroscopy. Increasing the W target power resulted in an almost liner increase in the W content, reduced the hardness and the sp³/sp² ratio in the films, while it increased the surface roughness and promoted formation of WC nanoparticles. Tribological properties were studied by conducting sliding reciprocating testing. Wear tracks were analyzed with Raman spectroscopy and 3D optical profilometry. Increasing the W content in the films (increasing target power) resulted in a reduction of both, the friction coefficient and wear rate. The film deposited at 80 W target power (~8 at. % W) exhibited the lowest friction coefficient (0.15) and wear rate (6x10^-7 mm³N^-1m^-1). The observed low friction and wear rate were attributed to the particular nanocomposite structure of the films involving a fine distribution of WC nanoparticles surrounded by a sp² dominant carbon network. The present W-DLC nanocomposite films offer a highly desirable combination of low friction and low wear rate.

Abstract: ZnO films were deposited by magnetron sputtering using RF power supply, in order to study the effect of substrates on quality of the prepared films. Then, growth of the ZnO films on thin AlN buffer layer and Si(100) substrates were characterized using different techniques. The surface morphology was investigated by means of scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). The structural properties were investigated via X-ray diffraction (XRD) patterns, Rocking Curve as well as Pole figures. The ZnO films were textured and they had preferred orientation (002) and the crystallinity was better for ZnO/Si in the used growth conditions. The XRD results were confirmed by HRTEM. Optical properties were analyzed by photoluminescence (PL), as well as electrical characteristics were performed by C-V and I-V measurements. The dispersion orientation of these films, as indicated via the FWHM (rocking curves), is small for thin ZnO/Si. These results are considered as hopeful for piezoelectric applications.

Abstract: The layers of Al and Co are deposited successively on SiO₂ substrates using magnetron sputtering technique. Thereafter, annealing is provided at 1100°C in 2-195 minutes in the muffle furnace. The color of the layers is changed gradually from brown at 2 minutes to blue at 195 minutes. The change of the structure during annealing is seen from the Raman spectra. The line at 188 cm^-1 shifts to 203 cm^-1, which shows the substitution of the Co³⁺ with less massive Al³⁺ ions during the formation of CoAl₂O₄. The most intensive peak at 505 cm^-1 disappears after the process is finished in 60 minutes. the annealing is provided in the Ar+O₂ atmosphere with 5% and 0.07% of oxygen in the temperature range from 850 to 1100 °C. The film with the layered structure is obtained at the low oxygen conditions.

Abstract: In this work, the adhesion and corrosion resistance of TiN coating by magnetron sputtering on stainless steel substrates under different bias voltages conditions (-50 V and-100 V) was investigated. AFM was used for surface roughness and grain size analysis, XRD for phase identification, Rockwell C for adhesion and nanoindentation for hardness and elastic modulus. According to AFM the coating deposited at-100V bias had decreased surface roughness, the value decreased from 2.7 nm (for-50V sample) to 1.8 nm, this was due to an etching like process which occurs when ions with higher energies start hitting the surface. The coated samples came under HF1 adhesion parameter which is the highest class of adhesion in the model on the basis of Rockwell C adhesion test. nanoindentation hardness and elastic modulus results of-50 V and-100V were found to be 224 GPa and 182 GPa, respectively and the value of hardness, 16 GPa and 22 GPa, respectively. The corrosion behavior of TiN coatings were studied in 3.5wt. % NaCl solutions using Tafel Extrapolation, Cyclic Polarization and Open Circuit Potential. It was noted on the basis of these corrosion tests that, as bias voltage is increased, it leads to the formation of more densely packed, fine grained columnar structures with less pores, which decreases the chances of corrosion. .