Grid-assisted Magnetron Sputtering Research Articles

Morphology of Al Thin Films Deposited Under Different Magnetic Field Configurations by Grid-assisted Magnetron Sputtering

Morphology of Al Thin Films Deposited Under Different Magnetic Field Configurations by Grid-assisted Magnetron Sputtering

Evaluating residual stresses in compositionally graded TiN films via ab initio and Rietveld simulation

The grazing incidence X-ray diffraction (GIXRD) stress measurement method, based on the classic sin2ψ method, is a well-established procedure for the evaluation of compressive residual stresses (CRS) in thin deposited films. Problems arise when using this approach in single-phase compositionally graded films, since both mechanical and diffraction properties vary with film depth. A method of obtaining CRS gradient was developed which consists in simulating a stressed GIXRD pattern via Rietveld simulation and ab initio obtained X-ray elastic constants (XECs) in order to evaluate the stress profile across the film. This work successfully describes the CRS profile of compositionally graded TiN films obtained by Grid Assisted Magnetron Sputtering (GAMS), insofar as the biaxial stress assumptions are valid and within the limits imposed by the sin2ψ method.

Change with the Reactive Deposition Mode in Crystallographic and Mechanical Properties of Titanium Aluminum Nitride Coatings Obtained Via Grid-Assisted Magnetron Sputtering

Change with the Reactive Deposition Mode in Crystallographic and Mechanical Properties of Titanium Aluminum Nitride Coatings Obtained Via Grid-Assisted Magnetron Sputtering

Use of ball-cratering wear test and nanoscratching test to compare the wear resistance of homogeneous and functionally graded titanium nitride thin films

Homogeneous (HM) and functionally graded (FG) TiN thin films were produced by the grid-assisted magnetron sputtering (GAMS) technique. The joint use of ball-cratering micro-abrasive wear test (BCMA) and nanoscratching (NN) test was proposed and carried out to evaluate the wear resistance of TiN films. The results showed an increase of 33.3% wear resistance in the FG TiN thin film, when compared with the HM TiN thin film. This result was justified by the higher resistance to nucleation and propagation of cracks and higher level of adhesion to the substrate by the FG TiN thin film, validated through the NN tests.

Corrosion resistance of functionally graded TiN/Ti coatings for proton exchange membrane fuel cells

Bipolar Plates (BPP) are important components of proton exchange membrane fuel cell (PEMFC) stacks. In the development of innovative fuel cell designs, it is advantageous to use aluminum for these applications, however, this material lacks the necessary corrosion resistance. Since the performance of PEMFC stacks depends on BPP properties, in particular, corrosion resistance, depositing titanium nitride (TiN) thin films onto aluminum substrates may improve their efficiency and durability. The present work focuses on improving corrosion resistance and hydrophobicity of TiN/Ti by using N graded films deposited onto aluminum substrates (AA-1100) by grid-assisted magnetron sputtering (GAMS). Electrochemical impedance spectroscopy (EIS) and potentiodynamic and potentiostatic polarization are used to investigate the performance of the substrate/film system at room temperature and 70 °C, thus simulating a prototypic PEMFC electrolyte environment. Electrochemical test results showed that graded TiN films improved corrosion resistance when compared with both the homogeneous films and the AA1100 uncoated substrate. Furthermore, contact angle results reveal improved hydrophobicity for both homogeneous and graded TiN coatings when compared with the AA1100 substrate.

Alternative anode geometry for magnetron sputtering

Anode geometry can play a crucial role in magnetron sputtering deposition. In this work, we investigated the use of five different ring anodes placed in front of the target. Their effects in the current-voltage relations and the hysteresis curves in reactive deposition were compared to conventional magnetron sputtering and grid-assisted magnetron sputtering. We measured the current-voltage relations in Ar discharges using Al and Ti targets. The hysteresis curves were obtained in Ar/N2 and Ar/O2 atmospheres for both targets. By changing the ring internal diameter, we change the ratio between the ring internal diameter and the target diameter. The results show that this ratio is determinant to the current-voltage relations and substrate floating potential, which can vary from negative to positive values relative to the ground. We also report hysteresis in the substrate floating potential during reactive deposition. The analysis of these hysteresis curves shows that the substrate floating potential can decrease to values around – 60 V depending on target/reactive gas combination.

Mechanical properties of homogeneous and nitrogen graded TiN thin films

Coating of metallic industrial parts with titanium nitride (TiN) is widely used with the aim to improve the mechanical and tribological properties of these parts. In the present work, TiN films were deposited via grid-assisted magnetron sputtering on aluminium substrates. The films were grown under different substrate bias voltage (-40, -75 or -100 V) and two different modes of nitrogen supply during deposition (constant and variable), resulting in homogeneous and N-graded films. The results of tension fractures observed in situ were correlated with the film microstructure and residual stress levels obtained through grazing incidence X-ray diffraction measurements. Elastic properties of the films were analysed via nanoindentation and adhesive properties were investigated by nanoscratching tests. Results show that the delamination load of the graded films is higher than in the homogeneous counterparts, suggesting the graded film have improved tribological properties.

Multiphase titanium suboxides films grown on glass substrate: Surface energy, wettability and morphology analysis

Thin films of titanium suboxides were deposited through grid-assisted magnetron sputtering on glass substrates at different temperatures (room, 373 K, 473 K, 573 K and 673 K). The physical, chemical and morphological properties of the samples were measured by grazing incidence X-ray diffraction (GIXRD), contact angle measurement, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) techniques. GIXRD and XPS results indicate a miscellaneous of suboxides (TiOx) growing on substrate at temperatures of 473 K, 573 K and 673 K. Contact angle analyses show significant increase in surface energy after irradiation of the films with UV light. Results allow us to conclude that multiphase TiOx films present photoinduced hydrophilicity, and may be employed in photocatalysis and self-cleaning applications, similarly to stoichiometric TiO2.

Grid-assisted magnetron sputtering deposition of nitrogen graded TiN thin films

Titanium Nitride (TiN) films were obtained using the grid-assisted magnetron sputtering deposition technique on Al substrates in two conditions: under constant and variable nitrogen concentration along the thin solid film thickness. The formation of a film with variable N concentration (herein referred as graded film) was confirmed using energy filtered transmission electron microscopy, X-ray photoelectron spectroscopy and grazing incidence X-ray diffraction. The TiN thin films microstructures were also analysed using scanning and transmission electron microscopies (SEM and TEM). The viability of synthesizing TiN thin films with variable N concentration is herein proposed as an alternative method for tailoring the properties of such functional coating materials.

Target power influence on optical and electrical properties of amorphous titanium oxide deposited by reactive grid-assisted magnetron sputtering

Titanium oxide (TiOx) thin films were deposited by reactive grid-assisted magnetron sputtering on glass substrates as function of the target power. Films were characterized by mechanical profilometry, optical spectrophotometry, four-probe method, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) in order to investigate the effect of the target power on electrical, structural and electronic properties. The electrical properties were measured after deposition and one year later to evaluate the stability of the sheet resistance. Data for suboxides show the decreasing of the optical gap, sheet resistance and density of electronic states in conduction and/or valence bands, and increasing of the optical gap entropy, optical absorption and film thickness as the target power increases. The absorption coefficient indicates the presence of mid-gap states in suboxides, inducing the redshift of the absorption onset. The TiO2 reference sample presents only a single transition in the ultraviolet part. XRD show amorphous structure for all samples. Ti2p and O1s spectra from XPS indicate an oxidized surface with a small contribution of Ti3+ states in either titanium suboxide or dioxide, where the surfaces with the highest concentrations of hydroxyl radicals presented the best stability of the sheet resistance after one year.

Optical and electrical properties of Ti suboxides grown by reactive grid-assisted magnetron sputtering

In this paper, the structural, optical, and electrical properties of titanium suboxides (TiOx) are investigated. The sub-stoichiometric films were obtained by grid-assisted magnetron sputtering in an atmosphere of Ar and O2 at different oxygen concentrations in gas flow rate. The samples were characterized by profilometry, X-ray diffraction, and X-ray photoelectron spectroscopy. The optical and electrical properties were measured by optical spectrophotometry and the van der Pauw method, respectively. Oxygen deficiency (x < 2) decreases the film resistivity without doping with other elements and shifts the absorbance to longer wavelengths, in consequence of a second optical gap in the TiOx films. The optical properties can be controlled, changing the visual aspect of the films from “mirror-like” to transparent, through opaque yellow and bluish films.

Nb-doped Ti2O3 Films Deposited Through Grid-Assisted Magnetron Sputtering on Glass Substrate: Electrical and Optical Analysis

This study was supported by the Government of the State of Santa Catarina through the FUMDES and FAPESC programs.

Shifts in average energy of deposited atoms by magnetron sputtering through modifications in anode geometry: a simulation study

The deposition of titanium and gadolinium films by magnetron sputtering was simulated by using software SiMTra. The main goal is to analyze the average energy of deposited atoms as a function of argon pressure at different anode geometries. Two different anode configurations were used: a grid inserted between the target and the substrate, in the so-called grid-assisted magnetron sputtering, and a disk with different apertures. In the case of grid anode, simulations were also performed with a shutter in front of the substrate. The presence of the grid increases the average energy of atoms arriving at the substrate for pressures in the range between 1.0 and 8.0 Pa. The disk anode also changes the average energy, but such effect depends on the size of aperture.

Langmuir Probe Measurements in a Grid-Assisted Magnetron Sputtering System

The grid-assisted magnetron sputtering is a variation of the magnetron sputtering commonly used for thin film deposition. In this work, Langmuir probe measurements were performed in such a system by using the grid under two basic and practical electrical conditions, i.e., floating and grounded. The results show that grounding the grid leads to an enhancement of the plasma confinement and to increases in both floating and plasma potential, as inferred from the probe characteristics. The grounded grid drains electrons from the plasma, acting as an auxiliary anode and reducing the plasma diffusion toward the chamber walls. For the same discharge current, the improved confinement results in a lower electron temperature when compared to floating condition, although the electron densities are comparable in both cases.

Pulsed bias effect on roughness of TiO2:Nb films deposited by grid assisted magnetron sputtering

Abstract In this work Nb-doped TiO2 (TiO2:Nb) films were deposited by reactive sputtering. The substrate was biased with negative pulses to change the energy of the ions nearby the sample surface during the deposition. As consequence, the film crystalline structure and roughness were changed. It was verified that higher energy favours the rutile growth with a higher roughness, even under low temperature as 300°C, and the material structure can be controlled by setting the duty cycle, voltage and frequency of the switched power supply applied to the substrate.

Drude’s Model Optical Parameters and the Color of TiNx Films Obtained Through Reflectivity Measurements

Titanium nitride (TiN) has been applied as decorative coating due to its high reflectivity and goldish color, having high hardness and wear resistance. In the present work, TiNx films were deposited by grid-assisted magnetron sputtering. The color and reflectivity were investigated by spectrophotometry as a function of the working gas ratio N2/Ar used during films deposition. The crystalline phases were identified by X-ray diffraction pattern (XRD). The TiNx plasma frequency (ω p) and the relaxation time (τ) were determined by fitting the experimental reflectivity curves, according to the Drude model. The color parameters obtained by the CieLab method were used to compare TiNx films with gold film.

Pulsed bias effect on crystallinity and nano-roughness of Ti6Al4V-N films deposited by grid assisted magnetron sputtering system

This paper reports the effect of pulsed bias in comparison with DC bias on reactive deposition of Ti6Al4V-N films, obtained by Grid Assisted Magnetron Sputtering. The results obtained by X-Ray diffraction (XRD), Energy Dispersive X-ray Fluorescence Spectrometer (EDX) and Atomic Force Microscopy (AFM) show that bias condition affects the crystalline texture and change the roughness and morphology of the films. The DC bias favors the film crystallinity, however the pulsed bias produces smoother films.

Unusual behaviour of current–voltage relations in an unbalanced grid-assisted magnetron sputtering system

Current–voltage relations were measured in an unbalanced grid-assisted magnetron sputtering system at different inter-electrode distances and magnetic field configurations. The intensity and configuration of the magnetic field were adjusted through an electromagnetic coil placed at the magnetron centre. This scheme allows observation of the current–voltage relations under conditions of weak and strong plasma confinement. Surprisingly, for some inter-electrode distances, a decreasing discharge current with increased magnetic field was observed. This unusual behaviour in grid-assisted magnetron discharges can be useful for a better understanding of abnormal glow discharges assisted by a magnetic field.

High adhesive metal laminate manufacturing by low energy ion cascade treatments

Highly adhesive Cu clad laminates (CCL) without oxygen plasma treatment were fabricated by introducing Ti layer using grid assisted magnetron sputtering. The interfaces of polyimide and titanium obtained were studied by XPS. The results give evidence for the formation of Ti–O–C chemical bonds between two sides of the interface. These chemical bonds are believed to be responsible for the observed mechanical strength of the CCL bonding.

Deposition of TiO x thin film using the grid-assisting magnetron sputtering

This paper presents a modification to conventional magnetron sputtering systems. The introduction of a grid in front of the target increases metal ion ratio in the plasma. By using optical emission spectroscopy (OES) and observing both Ti neutral and Ti ion, the relative ionization could be qualitatively extended to grid-attached magnetron sputtering as compared with conventional magnetron systems. Experiments clearly demonstrate microstructural cross-sectional TEM analysis of the titanium oxide film changes from a columnar-like (anisostropic) structure to a homogenous structure (isotropic), and resulting in a high refractive index. It is believed that more energetic ion bombardment induced the structural changes in films in the case of grid-assisted magnetron sputtering.