scholarly journals Investigating the effect of nitrogen on the structural and tribo-mechanical behavior of vanadium nitride thin films deposited using R.F. magnetron sputtering

Author(s):  
Linda Aissani ◽  
Mamoun Fellah ◽  
Ablel Hakim Chadli ◽  
Mohammed Abdul Samad ◽  
Abderrahmane Cheriet ◽  
...  

AbstractMagnetron sputtering is one of the most commonly used deposition techniques, which has received considerable attention in industrial applications. In particular, owing to its compatibility with conventional fabrication processes, it can produce and fabricate high-quality dense thin films of a wide range of materials. In the present study, nitrogen (N) was combined with pure vanadium in order to form binary nitride to improve its mechanical and tribological performance. To evaluate the influence of nitrogen on the structure of the as-deposited vanadium nitride (VN) coatings, the following techniques were used: XPS, XRD, SEM, AFM and optical profilometry. The residual stresses were determined by the curvature method using Stoney’s formula. The hardness and Young’s modulus were obtained by nanoindentation measurements. The friction behavior and wear characteristics of the films were evaluated by using a ball-on-disk tribometer. The obtained results showed that the N/V ratio increased with increasing the N2 flow rate while the deposition rate decreased. The preferred orientation was changed from (200) to (111) as the N2 flow rate increased with the presence of V–N and V–O binding energies as confirmed by XPS analysis. The nitrogen addition resulted in a columnar morphology and a fine structure with fine surface roughness. The VN thin film containing 49.5 at.% of nitrogen showed the best performance: highest mechanical properties (hardness = 25 GPa), lowest friction coefficient (μ = 0.37) and lowest wear rate (Ws = 2.72 × 10−5 mm3N−1 m−1). A good correlation between the film microstructure, crystallite size, residual stress and mechanical and tribological properties was observed.

Coatings ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 385 ◽  
Author(s):  
Asim Aijaz ◽  
Fabio Ferreira ◽  
Joao Oliveira ◽  
Tomas Kubart

Hydrogen-free diamond-like carbon (DLC) thin films are attractive for a wide range of industrial applications. One of the challenges related to the use of hard DLC lies in the high intrinsic compressive stresses that limit the film adhesion. Here, we report on the mechanical and tribological properties of DLC films deposited by High Power Impulse Magnetron Sputtering (HiPIMS) with Ne as the process gas. In contrast to standard magnetron sputtering as well as standard Ar-based HiPIMS process, the Ne-HiPIMS lead to dense DLC films with increased mass density (up to 2.65 g/cm3) and a hardness of 23 GPa when deposited on steel with a Cr + CrN adhesion interlayer. Tribological testing by the pin-on-disk method revealed a friction coefficient of 0.22 against steel and a wear rate of 2 × 10−17 m3/Nm. The wear rate is about an order of magnitude lower than that of the films deposited using Ar. The differences in the film properties are attributed to an enhanced C ionization in the Ne-HiPIMS discharge.


Coatings ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 246 ◽  
Author(s):  
Z. Hubička ◽  
M. Čada ◽  
A. Kapran ◽  
J. Olejníček ◽  
P. Kšírová ◽  
...  

A reactive high-power impulse magnetron sputtering system (HiPIMS) working in Ar + H2S gas mixture was investigated as a source for the deposition of iron sulfide thin films. As a sputtering material, a pure Fe target was used. Plasma parameters in this system were investigated by a time-resolved Langmuir probe, radio-frequency (RF) ion flux probe, quartz crystal monitor modified for measurement of the ionized fraction of depositing particles, and by optical emission spectroscopy. A wide range of mass flow rates of reactive gas H2S was used for the investigation of the deposition process. It was found that the deposition rate of iron sulfide thin films is not influenced by the flow rate of H2S reactive gas fed into the magnetron discharge although the target is covered by iron sulfide compound. The ionized fraction of depositing particles decreases from r ≈ 40% to r ≈ 20% as the flow rate of H2S, QH2S, changes from 0 to 19 sccm at the gas pressure around p ≈ 1 Pa in the reactor chamber. The electron concentration ne measured by the Langmuir probe at the position of the substrate decreases over this change of QH2S from 1018 down to 1017 m−3


2018 ◽  
Vol 775 ◽  
pp. 238-245 ◽  
Author(s):  
Thitinai Gaewdang ◽  
Ngamnit Wongcharoen

In this paper, copper oxide (CuOx) thin films with amorphous phase were prepared on glass substrates by reactive dc magnetron sputtering. The influence of the flow rate of O2 on the structural, optical and electrical properties of the as-deposited films was systematically studied. XRD revealed that the as-deposited films remained amorphous in the whole range of adjusted oxygen flow rate. Surface morphology and nanoparticle size of the films were observed by AFM. Electrical resistivity and Hall effect measurements were performed on the films with van der Pauw configuration. The positive sign of the Hall coefficient confirmed the p-type conductivity in all studied films. From temperature-dependent electrical conductivity of the films prepared at R(O2) of 1.5 sccm, it was show that three types of behavior can be expected, nearest-neighbor hopping at high temperature range (200-300 K), the Mott variable range hopping at low temperature (110-190 K) and Efros-Shklovskii variable range hopping at very low temperature (65-100 K). Some important parameters corresponding to Mott-VRH and ES-VRH like density of localized states near the Fermi level, localization length, degree of disorder, hopping distance and hopping energy were determined. These parameters would be helpful for optimizing the performance of photovoltaic applications.


2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Yu-Wei Lin ◽  
Chia-Wei Lu ◽  
Ge-Ping Yu ◽  
Jia-Hong Huang

This study aims to investigate the effects of nitrogen flow rate (0–2.5 sccm) on the structure and properties of TiZrN films. Nanocrystalline TiZrN thin films were deposited on Si (001) substrates by unbalanced magnetron sputtering. The major effects of the nitrogen flow rate were on the phase, texture, N/(Ti + Zr) ratio, thickness, hardness, residual stress, and resistivity of the TiZrN films. The nitrogen content played an important role in the phase transition. With increasing nitrogen flow rate, the phase changed from mixed TiZr and TiZrN phases to a single TiZrN phase. The X-ray diffraction results indicated that (111) was the preferred orientation for all TiZrN specimens. The N/(Ti + Zr) ratio of the TiZrN films first increased with increasing nitrogen flow rate and then stabilized when the flow rate further increased. When the nitrogen flow rate increased from 0.4 to 1.0 sccm, the hardness and residual stress of the TiZrN thin film increased, whereas the electrical resistivity decreased. None of the properties of the TiZrN thin films changed with nitrogen flow rate above 1.0 sccm because the films contained a stable single phase (TiZrN). At high nitrogen flow rates (1.0–2.5 sccm), the average hardness and resistivity of the TiZrN thin films were approximately 36 GPa and 36.5 μΩ·cm, respectively.


2005 ◽  
Vol 490-491 ◽  
pp. 589-594 ◽  
Author(s):  
Yao Gen Shen

Thin films of molybdenum nitride (MoNx with 0≤x≤0.35) were deposited on Si(100) at room temperature using reactive DC magnetron sputtering. The residual stress of films was measured as a function of sputtering pressure, nitrogen incorporation, and annealing temperature by wafer curvature-based technique. It was found that the stress of the films was strongly related to their microstructure, which depended mainly on the incorporation of nitrogen in the films. The film stresses without nitrogen addition strongly depended on the argon pressure and changed from highly compressive to highly tensile in a relatively narrow pressure range of 0.8-1.6 Pa. For pressures exceeding ~5.3 Pa, the stress in the film was nearly zero. Cross-sectional transmission electron microscopy indicated that the compressively stressed films contained a dense microstructure without any columns, while the films having tensile stress had a very columnar microstructure. High sputtering-gas pressure conditions yielded dendritic-like film growth, resulting in complete relaxation of the residual tensile stresses. It was also found that the asdeposited film was poorly ordered in structure. When the film was heated at ~775 K, crystallization occurred and the stress of the film drastically changed from –0.75 to 1.65 GPa. The stress development mechanism may be due to volumetric shrinkage of the film during crystallization.


2011 ◽  
Vol 130-134 ◽  
pp. 23-26 ◽  
Author(s):  
Shao Feng Yan ◽  
Kai Ge Miao

The Al2O3 films doped with Ce3 + were deposited on slides by the medium-frequency reaction magnetron sputtering process, to which the power is constant, Ar flow rate 70 sccm, O2 flow rate 25~45sccm and sputtering time 90min at room temperature. The relationship between the luminescent properties of Al2O3:Ce3 + films and the doped amount of Ce3 + in the films was studied. The presence of Ce3 + and stoichiometry of those films were determined. It was observed that the total luminescence intensity increases and the peak positions are strongly dependent on Ce3+ concentration in the films. The analysis of luminescent excitation spectra showed that the luminance is due to the Ce3+ concentration in the cerium chloride aggregate formed in the films.


2006 ◽  
Vol 11-12 ◽  
pp. 167-170 ◽  
Author(s):  
Lei Miao ◽  
T. Jiang ◽  
Sakae Tanemura ◽  
Masaki Tanemura ◽  
M. Mori ◽  
...  

Photochromic material Ag-TiO2 thin films are fabricated on quartz substrate by dual -target helicon magnetron sputtering. The phototchromic behavior is investigated for the sample loaded with 90% Ag. Spheres, ellipsoids and polyhedra shape of Ag particles with wide range size (5∼100 nm) are dispersed in the TiO2 amorphous matrix observed by transmission electron microscopy. The spectral hole burned by the irradiation of laser at the wavelength 532 nm can be explained by a particle-plasmon-assisted electron transfer from Ag nanoparticles to TiO2 and subsequent trapping by adsorbed molecular oxygen. Moreover, the mechanism of the slow recovery after photochromism is suggested as a slow thermal release of electrons from oxygen trapping centers and subsequent capture into the Ag nanoparticles.


2013 ◽  
Vol 770 ◽  
pp. 169-172 ◽  
Author(s):  
Prayoon Suapadkorn ◽  
Worawarong Rakreungdet ◽  
Tula Jutarosaga ◽  
Wattana Samanjit

Nitrogen - doped tin oxide (N-doped SnO2) thin films were prepared on unheated glass substrate by dc magnetron sputtering of a Sn target in gas mixtures of O2 and N2. The N2 flow rates were varied from 0 to 15 SCCM with the same working pressure of 1×10-2 Torr. The as-deposited films were annealed in vacuum at 400 °C for 1 h. The films structure, electrical properties and optical properties were characterized by X-ray diffraction (XRD), 4-point probe and Hall effect measurement and portable fiber optic UV-vis spectrometer, respectively. The observed XRD patterns of films showed preferred (101) orientation of the SnO2 tetragonal structure. The average crystalline size of the (101) diffraction peak decreased from 5.10 to 4.07 nm with N2 flow rate increased. Hall measurement indicated that resistivity increased and carrier concentrations decreased as N2 flow rate increased. The carrier concentrations decreased because N atoms substituted oxygen atom in SnO2 lattice. The N atoms may forms acceptor level in SnO2 band gap resulting in hole generation. The electron concentration from intrinsic defect were neutralized with the hole concentration. The carrier concentration decreased from 3.42×1017 cm-3 for un-doped SnO2 to the order of 1014 cm-3. The average percent transmittance of un-doped SnO2 of about 77.5% in visible range (400-700 nm) decreased to 60% with increasing N2 flow rate. The optical band gap decreased from 3.64 eV for un-doped SnO2 to 3.45 eV for N-doped SnO2 films.


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