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International audience; The p-type Ge-doped (0, 1, 4 and 7 at.%) Mg

Metallic platinum&ndash, titanium coatings were deposited by co-sputtering of two metallic Pt and Ti targets in pure argon atmosphere. The titanium concentrations varied from 0 to 47 atomic percent and were adjusted as a function of the current applied to the titanium target. The structural and chemical features of these films were assessed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). All as-deposited coatings exhibit a perfect covering of the alumina pellets&rsquo, substrate surface. The coatings containing more than 4 at.% Ti are amorphous, whereas the others crystallize in the face-centered cubic (fcc) structure of platinum. After an annealing treatment under air for 2 h, all of the coatings adopt the fcc structure with a crystallization temperature depending on the titanium content. For titanium concentrations higher than 32 at.%, the TiO2 phase appears during the annealing treatment. For the smaller film thickness of Pt&ndash, Ti alloys (15 nm), the Ostwald ripening mechanism is observed by SEM increasing the annealing temperature regardless of the content of Ti. The film resistivity measured at room temperature is lower than 7 10&minus, 4 &Omega, &middot, cm and increases with the temperature to achieve an insulating behavior (in air and reducing atmosphere Ar-H2 (90-10) at 1123 K the resistivity is &rho, 10+36 &Omega, cm). When the thickness of intermetallic Pt3Ti layer is higher than 50 nm, the coating is continuous and the resistivity is below 5 10&minus, cm in air and in reducing atmosphere (Ar with 10% of H2) up to 1273 K.

International audience; In this paper, novel self-powered, solar-blind UV photodetector (PD) designs based on a ZnO thin-film with engineered back metal layer (BML) were fabricated by RF magnetron sputtering and e-beam evaporation techniques. An exhaustive study concerning the impact of dissimilar BML (Au and Ni) on the device structural, optical and electrical properties was carried out. The measured I–V curves illustrated an asymmetrical behavior, enabling a clear and distinctive photovoltaic mode. Superb sensitivity of 107, high ION/IOFF ratio of 149dB, ultralow dark-noise current less than 11pA and responsivity exceeding 0.27A/W were reached for the prepared ZnO-based UV-PDs in self-powered mode. The role of the engineered BML in promoting effective separation and transfer of the photo-induced carriers was discussed using the band-diagram theory. The influence of the annealing process on the UV-sensor performance was also investigated. The annealed device at 500°C demonstrated a lower dark current of a few picoamperes and a high rejection ratio of 2.2:103, emphasizing its exciting visible blindness characteristics. Therefore, the use of an engineered BML with optimized annealing conditions open up new perspectives to realizing high-performance, self-powered solar-blind UV-PDs based on simple thin film-ZnO structure strongly desirable for various optoelectronic applications.

International audience; Tungsten oxide thin films were prepared by DC magnetron sputtering. The reactive gas pulsing processwas implemented to modify tungsten and oxygen concentrations in the films. A rectangular pulsingsignal was used with a pulsing period fixed at P ¼ 16 s, whereas the duty cycle a was systematicallychanged from a ¼ 0e100% of P. The chemical composition of the films showed a gradual increase ofoxygen-to-tungsten concentrations ratio from 0 to more than 3.0 as a function of the duty cycle. Filmsbecame poorly crystallized and even amorphous with an increase of the oxygen content. Similarly, atypical columnar structure was observed for pure or oxygen-rich tungsten films, which vanished whenthe duty cycle was higher than a few % of P. The optical transmittance in the visible range of WOx filmsdeposited on glass also showed a progressive change from absorbent to transparent as the duty cycle wasincreased. Electronic transport properties including conductivity, carrier mobility and concentration alsodemonstrated the controlled and regular evolution of the electrical properties from metallic to insulatorwhen the duty cycle and thus oxygen concentration in the films changed from pure tungsten to overstoichiometricWO3 compound.

Electrical resistivity of tilted columnar thin films is theoretically and experimentally investigated considering the anisotropic structure of the columns. To this end, W and W Cu thin films were deposited by the GLAD co-sputtering technique. These films were prepared using two different sputtering pressures: 2.5 × 10−3 and 15 × 10−3 mbar. Their morphological and crystallographic properties were studied in order to understand the correlations between some structural characteristics and electrical behaviors of these structured films. The influence of the sputtering pressure on the film's morphology was demonstrated and related to the electronic transport properties in these columnar films. For W Cu films, the copper was chemically etched in order to tune even more the electrical properties. By rotating the sample along its azimuthal axis, it was shown that the measured resistivity in the axis perpendicular to the particle flux is maximum, but decreases significantly along the axis parallel to the flux, leading to an anisotropic resistivity coefficient higher than 1.9 for some films. Similarly, an analytical model based-on effective medium approximations was successfully applied to determine the evolution of electrical resistivity versus azimuthal axis for W, W Cu and etched W Cu thin films.

This work reports on the preparation and characterization of zigzag nanostructured silver (Ag) doped zinc oxide (ZnO) films in order to improve piezoresistive response for pressure sensor applications. ZnO/Ag thin films were prepared by Glancing Angle Deposition (GLAD) from a metallic zinc (Zn) target DC sputtered in Ar + O2 atmosphere. The target was customized with different amounts of Ag pellets, symmetrically distributed along the preferential erosion area. It is shown that increasing the Ag content from 0 to 36 at.% in the ZnO/Ag system leads to a decrease of the electrical resistivity from 2.95 Ω cm to 1.52 × 10−5 Ω cm. The structural characterization of the thin films shows an evolution of the preferential growth, changing from a polycrystalline ZnO hexagonal-like structure, confirmed by the presence of dominant ZnO (002) and ZnO (101) diffraction peaks, to a Ag cubic (fcc)-like structure, as evidenced by the Ag (111), (200) and (220) diffraction peaks. The values of the gauge factor show a strong contribution both from Ag as well as from the zigzag nanostructure to the piezoresistive sensitivity of the films, in particular for Ag concentrations lower than 30 at.%. The tunneling distance between pairs of Ag conductive nanoregions was calculated for the different samples and in three different deformation regions, in order to evaluate its influence on the piezoresistive sensitivity. The results show that a longer distance between Ag particles, which varies from 0.1 to 10 nm, enhances the gauge factor, which ranges from 8 ± 1 to 120 ± 3, respectively., This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013 and project PTDC/EEI-SII/5582/2014. Armando Ferreira acknowledges the FCT for the SFRH/BPD/102402/2014 grant. Funding was also provided by the Region of Franche-Comté, the French RENATECH network. This work has also been supported by the EIPHI Graduate School (contract “ANR-17-EURE-0002”). Financial support from the Basque Government Industry Department under the ELKARTEK and HAZITEK programs is also acknowledged.

Inclined, zigzag and spiral Ti1-xCux films were co-sputtered by the Glancing Angle Deposition technique. Two distinct titanium (Ti) and copper (Cu) targets were used and the films were grown with a particle flow incidence angle α of 80°. The thin films had Cu contents ranging from 36 to 76 ± 5 at. %. The effect of increasing Cu incorporation on the electrical anisotropy, as well as the effect of columnar architecture variations on the morphological, structural and electrical properties of the films was evaluated and correlated with the particular their architectures. Main results show well-defined and highly inclined columns (with an average column angle β = 45° ± 5°) for all sputtering conditions. Quasi-amorphous thin films were obtained with low Cu contents (36 at. %), while crystalline Cu (111) + Ti3Cu (114) bi-component structures were achieved at high Cu concentrations (76 at. %). No permanent oxidation of the films was detected after a two-cycle RT-200 °C-RT (RT – room temperature) annealing in air. The two-dimensional representation of the resistivity anisotropy of the columnar and 2 zigzags films is shaped as an elongated ellipse along the xx direction, with a variation of the effective anisotropy, Aeff, at 200 °C from 1.4 to 2.9. The samples prepared with 2 spirals and the same Cu content (36 at. %) exhibit an isotropic behavior, with an Aeff value at 200 °C of 1.1. The overall results demonstrate the possibility to tune the thin films' morphology and electrical characteristics in order to obtain a set of properties that are suitable for the development of high performance materials, such as the case of resistance temperature detectors., This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013 and project PTDC/EEI-SII/5582/2014. Armando Ferreira acknowledges the FCT for the SFRH/BPD/102402/2014 grant. Funding was also provided by the Region of Franche-Comte, the French RENATECH network and performed in cooperation with the Labex ACTION Program (contract ANR-11-LABX-01-01). Financial support from the Basque Government Industry Department under the ELKARTEK and HAZITEK programs is also acknowledged.

International audience; Tungsten oxide thin films exhibiting an oriented columnar architecture were prepared by reactive co-sputtering. Two opposite W and WO3 targets focused on the center of the substrate were simultaneously sputtered using opposite and oblique angles of 80° from the substrate normal. The reactive gas pulsing process was used to adjust the films electrical resistivity. Different inclined columnar structures were produced and applied as gas sensors for dodecane detection. Morphology, structure and resistivity of the films were investigated and connected to the sensing performances measured from 373 to 773 K.

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Pure V thin films were dc sputtered with different pressures (0.4 and 0.6 Pa) and particle incident angles α of 0°, 20° and 85°, by using the GLancing Angle Deposition (GLAD) technique. The sputtered films were characterized regarding their electrical resistivity behaviour in atmospheric pressure and in-vacuum conditions as a function of temperature (40–550 °C), in order to control the oxidation process. Aiming at comprehending the oxidation behaviour of the samples, extensive morphological and structural studies were performed on the as-deposited and annealed samples. Main results show that, in opposition to annealing in air, the columnar nanostructures are preserved in vacuum conditions, keeping metallic-like electrical properties.

Flexible polyurethane substrates were coated with Ag:TiN thin films (N/Ti atomic ratio = 0.7; 10 at.% Ag), with different column inclinations (α = 0°, 40° and 80°) and architectures (columnar, zigzag with 2 and 4 periods), using the Glancing Angle Deposition (GLAD) technique. The coatings were characterized in order to assess the best thin film architecture to suit the bio-potential electrode applications. An abrupt increase of porosity of the samples was perceivable with increasing α angles (particularly from 40° to 80°). Hence, the sputtered films could be divided into dense (Ag:TiN 0° and Ag:TiN 40°) and porous (Ag:TiN 80°, Ag:TiN 80° 2Z and Ag:TiN 80° 4Z) samples. The electrochemical behaviour of the sampleswas consistently linked to the porosity differences,which was accompanied by an increase of the surface Ag content. Furthermore, the porous samples exhibited lower impedances (~104 Ωcm2 at 2 MHz), as well as electrochemical noise and drift rate values similar to those of the commercial Ag/AgCl electrodes. Hence, the porous Ag:TiN 80°, Ag:TiN 80° 2Z and Ag:TiN 80° 4Z porous Ag:TiN GLAD coatings seem to be the most promising architectures for the envisaged bio-potential electrode applications., This research is partially sponsored by FEDER funds through the programme COMPETE - Programa Operacional Factores de Competitividade, by national funds through FCT – Fundação para a Ciência e a Tecnologia, under the projects PEst-C/EME/UI0285/2011, PTDC/SAU-ENB/116850/2010, PTDC/CTM-NAN/112574/2009 and Programa Pessoa 2012/2013 Cooperação Portugal/França, Project no. 27306UA Porous architectures in GRAded CERamic thin films for biosensors — GRACER. The authors would also like to acknowledge to the European Union (FP7-PEOPLE Marie Curie IAPP, project 610950), to CEMUP for SEM analysis and Yantai Wanhua Polyurethanes Co., Ltd. for providing the thermoplastic polyurethane pellets. P. Pedrosa acknowledges FCT for the Ph.D. grant SFRH/BD/70035/2010.

© 2020 by the authors., This Special Issue contains a series of reviews and papers representing some recent results and some exciting perspectives focused on advanced strategies in thin films growth, thin films engineering by magnetron sputtering and related techniques. Innovative fundamental and applied research studies are then reported, emphasizing correlations between structuration process parameters, new ideas and approaches for thin films engineering and resulting properties of as-deposited coatings.

Tungsten films were prepared by DC magnetron sputtering using glancing angle deposition with a constant deposition angle &alpha, = 80&deg, A first series of films was obtained at a constant pressure of 4.0 &times, 10&minus, 3 mbar with the films&rsquo, thickness increasing from 50 to 1000 nm. A second series was produced with a constant thickness of 400 nm, whereas the pressure was gradually changed from 2.5 &times, 3 to 15 &times, 3 mbar. The A15 &beta, phase exhibiting a poor crystallinity was favored at high pressure and for the thinner films, whereas the bcc &alpha, phase prevailed at low pressure and for the thicker ones. The tilt angle of the columnar microstructure and fanning of their cross-section were tuned as a function of the pressure and film thickness. Electrical resistivity and surface elastic wave velocity exhibited the highest anisotropic behaviors for the thickest films and the lowest pressure. These asymmetric electrical and elastic properties were directly connected to the anisotropic structural characteristics of tungsten films. They became particularly significant for thicknesses higher than 450 nm and when sputtered particles were mainly ballistic (low pressures). Electronic transport properties, as well as elastic wave propagation, are discussed considering the porous architecture changes vs. film thickness and pressure.

Thin films of (CoCrCuFeNi) N x were deposited by direct current reactive magnetron sputtering. Two different targets were used. Thin films deposited from a solid near-equimolar target showed a Cu excess with segregation of Cu in the film resulting in the formation of a nanocomposite film. It was also not possible to reach fully stoichiometric nitride thin films with this target. To overcome this problem, a powder target with adjusted composition was used in a second series of experiments. As derived from longitudinal and transversal sound velocity measurements, a transition from the metallic face-centred cubic lattice to the nitride B1 (NaCl) structure is observed. The observed transition corresponds with the process change from the metallic regime at low nitrogen partial pressure to the poisoned regime at high nitrogen partial pressure. TEM measurements show a typical zone T growth with a strong (100) texture in the nitride regime, and reveal a mixing of the constituent metals at the nanometer scale. This study demonstrates that the constituent metals do not form binary nitrides, but a complex nitride is formed.

International audience; wo series of W-Cu thin films were developed by the GLAD co-sputtering technique. The films were produced with two separated W and Cu targets. Both targets were focused on the centre of the substrate and were simultaneously sputtered using opposite and oblique angles of 80° from the substrate normal. In the first series, the W and Cu target currents were inversely changed from 50 to 140. mA in order to tune the elemental concentrations and the microstructure. For the second series, a shield was added between W and Cu targets, perpendicularly to the substrate surface in order to prevent the cross-contamination of the targets. The target currents were varied similarly to the first series. Two argon sputtering pressures were used (0.42 and 1.0. Pa) in each series, with and without the shield.Microstructure showed a tuneable inclined columnar microstructure, which become normal to the substrate at high pressure. The crystallographic structure was not significantly influenced by the shield implementation but rather by the sputtering pressure. The W/Cu atomic concentration ratio varied between 0.2 and 5.5 as a function of the sputtering pressure and target currents and an anisotropic chemical composition was measured inside the columns. The wide range of DC electrical resistivities (3.6×10⁻⁷ to 5.7×10⁻⁵ Ωm) was discussed considering W and Cu target currents, high and low sputtering pressures and the use of a cross-contamination shield. The role of the microstructure was clearly shown since significantly higher resistivity was obtained at high pressure, as a function of the W/Cu atomic concentration ratio. W-Cu sputtered thin films grown at... (PDF Download Available). Available from: https://www.researchgate.net/publication/320080270_W-Cu_sputtered_thin_films_grown_at_oblique_angles_from_two_sources_Pressure_and_shielding_effects [accessed Apr 09 2018].

This work reports on the preparation and characterization of Zinc Oxide (ZnO) thin films, exploring their anisotropic electrical resistivity behaviour evolution as a function of the different preparation conditions. Results show that by increasing the oxygen content in the work gas flow, the electrical resistivity increases from about 2.4 x 10(-2) Omega.cm (common in fairly conductive-like materials) to values in order of M Omega.cm, which is typical of materials that vary from semiconducting to roughly insulating type. Regarding the thin films structural behaviour, a relatively clear evolution of the preferential growth becomes clear when preparing the films within the three different regimes. The X-ray diffraction (XRD) patterns revealed the development of a polycrystalline hexagonal-like structure, confirmed by the presence of dominant and very intense ZnO (002) and ZnO (101) diffraction peaks. A change in preferential growth was noticed with the change in the preparation conditions.By in-air annealing the samples from room temperature (RT) up to 200 degrees C and cooling down to RT again, the differences between the resistivity values along the xx and yy directions become significant, a clear sign of the anisotropic nature of the films. The anisotropy obtained during the annealing cycles of the films increased from 0.98 to 1.10 and, consequently, the Temperature Coefficient of Resistance, TCR, increased in both xx and yy directions, from TCRxx (and yy) similar to 9.0x10(-4) to TCRxx = 6.82 x 10(-3) and TCRyy = 5.97 x 10(-3) degrees C-1. Important also to note is that the increase of the grain size of the films showed to have a significant effect in the effective anisotropy, revealing to be a major factor to take into account., This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013 and project PTDC/EEI-SII/5582/2014 and by the Region of Franche-Comte, the French RENATECH network and performed in cooperation with the Labex ACTION program (contract ANR-11-LABX-01-01). A. Ferreira thanks the FCT for grant SFRH/BPD/102402/2014. Financial support from the Basque Government Industry Department under the ELKARTEK Program is also acknowledged., info:eu-repo/semantics/publishedVersion

International audience; We report on the observation of strongly anisotropic surface acoustic wave propagation on nanostructured thin films. Two kinds of tungsten samples were prepared by sputtering on a silicon substrate: a conventional thin film with columns normal to the substrate surface, and an oriented columnar architecture using the glancing angle deposition (GLAD) process. Pseudo-Rayleigh waves (PRWs) were imaged as a function of time in x and y directions for both films thanks to a femtosecond heterodyne pump-probe setup. A strong anisotropic propagation as well as a high velocity reduction of the PRWs were exhibited for the GLAD sample. For the wavevector k /2 π = 3 × 10 5 m −1 the measured group velocities v x and v y equal 2220 m s −1 for the sample prepared with conventional sputtering, whereas a strong anisotropy appears ( v x = 1600 m s −1 and v y = 870 m s −1 ) for the sample prepared with the GLAD process. Using the finite element method, the anisotropy is related to the structural anisotropy of the thin film’s architecture. The drop of PRWs group velocities is mainly assigned to the porous microstructure, especially favored by atomic shadowing effects which appear during the growth of the inclined columns. Such GLAD thin films constitute a new tool for the control of the propagation of surface elastic waves and for the design of new devices with useful properties.

International audience; W/WOx multilayered thin films have been deposited by DC reactive sputtering using the reactive gas pulsing process. It is implemented to produce regular alternations of metal-oxide compounds at the nanometric scale. Structure and growth have been investigated by high resolution transmission electron microscopy, scanning transmission electron microscopy, X-ray energy dispersive spectroscopy and electron energy loss spectroscopy. Regularity of tungsten-based alternations, quality of interfaces as well as oxygen presence through the multilayered structure have been determined and linked to the growth conditions. Chemical information was obtained from the energy dispersive X-ray spectroscopy and low-loss electron energy loss spectroscopy. As they can be related to the chemical composition of the periodic layers, the position and the broadening of the bulk plasmon peak were studied. For the smallest periods (

We analyze structure and composition of titanium-based metal/oxide periodic multilayers prepared by reactive sputtering. The reactive gas pulsing process is involved to periodically inject the oxygen gas during the multilayers deposition. This approach allows the growth of regular and tunable nanometric TiO2/Ti periods with thicknesses ranging from 14 to 50 nm. The interfacial layer between oxide and metallic layers is mainly the fcc-TiO phase as clearly pointed out by transmission electron microscopy and associated electron spectroscopies. In addition, sharp transitions are produced at Ti/TiO2 interfaces (with a high density of defects) whereas the smoothest ones are obtained at TiO2/Ti interfaces. Similarly, the real-time measurements of the target voltage vs. time correlate with periodic alternations formed by a mixture of amorphous + rutile TiO2 compound, the fcc-TiO phase and the hcp metallic Ti phase through the films thickness. An abrupt transition from metallic to oxidized sputtering mode takes place when oxygen is injected and correlates with the sharp Ti/TiO2 interface. On the other hand, when oxygen is stopped, the restoration to the metallic sputtering mode is longer and corresponds to the occurrence of the fcc-TiO phase at the smooth TiO2/Ti interfaces.

Titanium films were DC sputtered with a particle flux incidence angle of 80 degrees, using the Glancing Angle Deposition (GLAD) technique with increasing sputtering pressures from 0.2 to 1.5 Pa. This range of pressures is typically implemented for the deposition of thin films by the magnetron sputtering process. The main objective of this work was to study the anisotropic electrical resistivity behaviour of the different thin film nanostructures that were obtained. It is shown that low sputtering pressures (0.2-0.5 Pa) promote higher column angles beta with respect to the substrate normal (15 degrees, This work was supported by the Region of Franche-Comte, the French RENATECH network and performed in cooperation with the Labex ACTION program (contract ANR-11-LABX-0101). Funding was also provided by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013 and project PTDC/EEI-SII/5582/2014. Armando Ferreira acknowledges the FCT for the SFRH/BPD/102402/2014 grant. The authors thank financial support from the Basque Government Industry Department under the ELKARTEK Program., info:eu-repo/semantics/publishedVersion

International audience; The present study describes a sputtering and in situ vacuum electrical resistivity setup that allows a more efficient sputtering-oxidation coupling process for the fabrication of oxide compounds like vanadium dioxide, VO2. After the sputtering deposition of pure V thin films, the proposed setup enables the sample holder to be transferred from the sputtering to the in situ annealing + resistivity chamber without venting the whole system. The thermal oxidation of the V films was studied by implementing two different temperature cycles up to 550 °C, both in air (using a different resistivity setup) and vacuum conditions. Main results show that the proposed system is able to accurately follow the different temperature setpoints, presenting clean and low-noise resistivity curves. Furthermore, it is possible to identify the formation of different vanadium oxide phases in air, taking into account the distinct temperature cycles used. The metallic-like electrical properties of the annealed coatings are maintained in vacuum whereas those heated in air produce a vanadium oxide phase mixture.

International audience; We report on the evolution of anisotropic electrical resistivity versus temperature of titanium thin films. An oriented titanium film (1 μm thick) is sputter deposited by GLancing Angle Deposition (GLAD) using an incident angle α = 80° of the particle flux. Two parallel Ti electrodes cover this GLAD film. We measure the components of the conductivity tensor by the van der Pauw method during an annealing treatment in air ranging from 298 to 873 K. The average DC electrical resistivity ρ changes from 6.03×10-6 to more than 2.40×10-1 Ωm with the increasing temperature. The anisotropy ratio is A = 1.39 before annealing and reaches 12.4 for the highest temperatures. This enhanced anisotropy is interpreted assuming the oxidation of the porous GLAD titanium film.

International audience; Dc reactive sputtering was used to deposit tantalum metal/oxide periodic nanometric multilayers using the innovative technique namely, the reactive gas pulsing process (RGPP). Different pulsing periods were used for each deposition to produce metal-oxide periodic alternations included between 5 and 80 nm. Structure, crystallinity and chemical composition of these films were systematically investigated by Transmission Electron Microscopy (TEM) and Energy-dispersive X-ray (EDX) spectroscopy techniques. Moreover, electrical properties were also studied by the Van der Pauw technique.

International audience; Tungsten oxide WO3 thin films are prepared by DC reactive sputtering. The GLancing Angle Deposition method (GLAD) is implemented to produce inclined columnar structures. The incident angle α between the particle flux and the normal to the substrate is systematically changed from 0 to 80°. For incident angles higher than 50°, a typical inclined columnar architecture is clearly produced with column angles β well correlated with the incident angle α according to conventional relationships determined from geometrical models. For each film, the refractive index and extinction coefficient are calculated from optical transmittance spectra of the films measured in the visible region. The refractive index at 589 nm drops from n589 = 2.18 down to 1.90 as α rises from 0 to 80°, whereas the extinction coefficient reaches k589 = 4.27 × 10−3 for an incident angle α = 80°, which indicates that the films produced at a grazing incident angle become more absorbent. Such changes of the optical behaviors are correlated with changes of the microstructure, especially a porous architecture, which is favored for incident angles higher than 50°. Optical band gap Eg, Urbach energy Eu and birefringence Δn617, determined from optical transmittance measurements, are also influenced by the orientation of the columns and their trend is discussed taking into account the disorder produced by the inclined particle flux.

Titanium oxynitride thin films were deposited by dc reactive magnetron sputtering. A metallic titanium target was sputtered in argon, nitrogen and oxygen reactive atmosphere. Argon and nitrogen gases were continuously injected into the process whereas oxygen mass flow rate was pulsed during the deposition. By means of a home made pulsing technique, the oxygen gas was introduced using various modulation patterns of the mass flow rate: rectangle, exponential, sine, isosceles triangle, mounting and descending triangles. The period T of the pulse length was systematically changed from 10 to 400 s. Similarly, kinetics and poisoning phenomena of the titanium target by nitrogen and oxygen were investigated from real time measurements of the target potential and total sputtering pressure. Such diagnostics allowed understanding the advantageous role of the reactive gas pulsing process (RGPP) to synthesize titanium oxynitride compounds. Some requirements, especially the shape of the pulses and the period length were established to alternate the process between the oxidised and nitrided sputtering mode. With suitable and reversible operating conditions, the RGPP led to deposit tuneable titanium oxynitride coatings, usually difficult to reach by conventional reactive sputtering.

A new and original method, namely the reactive gas pulsing process (RGPP), was optimised to deposit titanium oxynitride thin films by dc reactive magnetron sputtering. Pure titanium target was sputtered in a reactive atmosphere composed of argon, nitrogen and oxygen. Argon and nitrogen gases were injected with a constant mass flow rate whereas oxygen was periodically supplied into the sputtering chamber. An exponential signal was generated to the oxygen mass flow meter with a constant pulsing period T = 45 s. During the injection time of the oxygen gas ( t ON time), the exponential shape was systematically modified in order to better control the amount of reactive gas introduced. Duty cycle was also changed and led to an extended alternation of the process between the nitrided and oxidised sputtering mode. Speed of poisoning of the titanium target surface by oxygen was calculated assuming real time measurements of the target potential. It was clearly shown that duty cycle and shape of the exponential signals used during oxygen injection are fundamental pulsing parameters. Both parameters must be taken into account in order to adjust and improve the monitoring of RGPP system for the deposition of titanium oxynitride coatings. Such approach prevents the full poisoning of the target surface by oxygen or nitrogen, and consequently, a wide range of oxynitride compounds can be easily reached.

Optical properties (refractive index and birefringence) of WO 3 thin films exhibiting columnar and zigzag nanostructures deposited by GLancing Angle Deposition are analyzed. The influence of the incident angle α of the sputtered particles and the number of zigzags N on these optical properties is determined. The experimental results show that refractive index of zigzag nanostructures evolves with the number of zigzags from n N = 0.5 = 2.02 to n N = 8 = 2.05 through a maximum n N = 4 = 2.29. The birefringence of columnar structures exhibits a similar trend when α changes from 0 to 80°. Birefringence of columnar and zigzag structures reaches both a maximum when α = 50° (Δ n α = 50° = 0.025). Experimental results favorably agree with the simulated ones calculated by means of the MEEP FDTD code.

Aiming at biosignal acquisition for bioelectrodes application, Ti-Ag thin films were produced by GLAD, in order to tailor their electromechanical properties. The electrical behaviour of the sculptured Ti-Ag thin films was studied with increasing annealing temperatures. The results revealed a good correlation with the set of morphological features displayed. With the increase of the vapour flux angle, a more defined structure was obtained, as well as a more porous morphology, which increased the electrical resistivity of the coatings. An important point consists in the recrystallization of Ti-Ag intermetallic phases due to the temperature increase (between 558 K and 773 K), which resulted in a sharp decrease of the electrical resistivity values., This work was supported by FEDER through the COMPETE Program and by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Project PEST-C/FIS/UI607/2014 and the project Matepro – Optimizing Materials and Processes”, ref. NORTE-07-0124-FEDER-000037”, co-funded by the “Programa Operacional Regional do Norte” (ON.2– O Novo Norte), under the “Quadro de Referência Estratégico Nacional” (QREN), through the “Fundo Europeu de Desenvolvimento Regional” (FEDER).

International audience; Composite silver–copper targets were sputtered for the first time in various reactive Ar–O2 mixtures to deposit the novel silver–copper oxides on glass substrates. The effect of two deposition parameters (oxygen flow rate and target composition) on the films structure was investigated. Depending on these two deposition parameters, three types of silver–copper oxides were synthesised using the reactive sputtering process: AgxCu2−xO, AgxCu4−xO3 and Ag1−xCu1+xO2. Although conventional processes led to the formation of silver–copper oxides with stoichiometric Cu/Ag atomic ratio, it was demonstrated that the reactive sputtering process was suitable to modify this ratio in the deposited films. Finally, the optical and electrical properties of the silver–copper oxides were investigated and compared to that of copper oxides exhibiting similar structures.

Sculptured thin films exhibiting a zigzag microstructure behave as a field of “microsprings”. Two theoretical approaches are presented to predict hardness, Young's modulus and stiffness of these coatings taking into account the film's geometry (zigzag) and the bulk material properties. Both models are based on the deformation of a single zigzag period caused by a normal force. In the first model (simple model), the column diameter is neglected during the deformation (no difference between the curvature radius of internal and external fibre). These differences are taken into account in the second model (enhanced model). The column section is not perfectly circular and so, both models are developed for circular and square sections. Models are tested on chromium zigzag multilayers sputter deposited with a constant thickness close to 1 μm and with half-period thickness Λ / 2 ranging from 50 to 1000 nm. Geometrical parameters are determined from Scanning Electron Microscopy observations. These parameters are used to calculate the theoretical values of Young's modulus, hardness, and stiffness. Experimental values of Young's modulus (ranging from 86 GPa for single layers up to 250 GPa for the film composed of 10 periods 100 nm thick) and hardness (ranging from 2 GPa for single layers up to 14 GPa for the film composed of 10 periods 100 nm thick) of chromium thin films are measured by nanoindentation. A quite good agreement is obtained between experimental and computed values. Such comparison proves that the proposed models are valuable to predict some mechanical properties of multilayers with a zigzag microstructure.

International audience; Tungsten and tungsten oxide periodic nanometric multilayers have been deposited by DC reactive sputtering using the reactive gas pulsing process. Different pulsing periods have been used for each deposition to produce metal-oxide periodic alternations ranging from 3.3 to 71.5 nm. The morphology, crystallinity and chemical composition of these films have been investigated by transmission electron microscopy and energy-dispersive X-ray spectroscopy techniques. The produced multilayers exhibited an amorphous structure and the composition stability of WO3 sub-layers has been pointed out. Moreover, electrical properties have also been studied by the van der Pauw technique. It revealed a clear stability of resistivity versus temperature for almost all samples and an influence of the multilayered structure on the resistivity behavior

Multilayered structures with a 40 nm period composed of titanium and two different titanium oxides, TiO and TiO 2 , were accurately produced by DC magnetron sputtering using the reactive gas pulsing process. These multilayers were sputtered onto Al 2 O 3 sapphire to avoid substrate compound diffusion during flash annealing (ranging from 350 °C to 550 °C). Structure and composition of these periodic TiO 2 /TiO/Ti stacks were investigated by X-ray diffraction, X-ray photoemission spectroscopy and transmission electronic microscopy techniques. Two crystalline phases α-Ti and fcc-TiO were identified in the metallic-rich sub-layers whereas the oxygen-rich ones were composed of a mixture of amorphous and rutile TiO 2 phase. DC electrical resistivity ρ measured for temperatures ranging from 25 to 200 °C was influenced by the thermal treatments. The temperature coefficients of resistance of these periodic TiO 2 /TiO/Ti multilayers were modified from 11.7 × 10 − 04 to − 8.81 × 10 − 04 K − 1 . Local changes of crystallinity were reported and the resistivity responses of these annealed films could be linked to the typical electrical behavior of a metal–oxide mixture.

International audience; Titanium-silver, Ti-Ag, thin films display excellent biocompatibility and reveal great potential to be used as conductive materials for prosthesis pressure sensors. In the frame of this work, TiAgx thin films were deposited onto silicon and glass substrates by DC magnetron sputtering, using a pure Ti target containing different amounts of Ag pellets. The films display Ag/Ti ratios varying from 0 up to 0.36, resulting in relatively large range of composition, which gave rise to varied morphological, structural and some selected property responses. For Ag/Ti ratios below 3.0 × 10−3, the TiAgx films exhibited similar behavior to those of standard Ti films. Above this critical value, the role of Ag becomes crucial on the crystallographic structure evolution, as well as on the surface morphology changes of the films. A gradual increase of the Ag/Ti ratio leads to the growth of Ti-Ag crystalline phases, whereas the long range order of Ti grains was reduced from 22 nm down to 7 nm. Similarly, a denser microstructure was developed with a reduction of the sharpness of the surface morphology. This critical Ag/Ti ratio (

Titanium thin films were deposited by DC magnetron sputtering. The glancing angle deposition (GLAD) method was implemented to prepare two series of titanium films: perpendicular and oriented columnar structures. The first series was obtained with a conventional incident angle α of the sputtered particles (α = 0°), whereas the second one used a grazing incident angle α = 85°. Afterwards, the films were annealed in air using six cycles of temperature ranging from 293 K to 773 K. DC electrical conductivity was measured during the annealing treatment. Films deposited by conventional sputtering (α = 0°) kept a typical metallic-like behavior versus temperature (σ300 K = 2.0 × 106 S m-1 and TCR293 K = 1.52 × 10-3 K-1), whereas those sputtered with α = 85° showed a gradual transition from metal to dielectric. Such a transition was mainly attributed to the high porous structure, which favors the oxidation of titanium films to tend to the TiO2 compound.

International audience; Multilayered structures with 14-50 nm periods composed of titanium and two different titanium oxides, TiO and TiO2, were accurately produced by DC magnetron sputtering using the reactive gas pulsing process. The structure and composition of these periodic TiO2/TiO/Ti stacks were investigated by X-ray diffraction and transmission electronic microscopy techniques. Two crystalline phases, hexagonal close packed Ti and face centred cubic TiO, were identified in the metallic-rich sub-layers, whereas the oxygen-rich ones comprised a mixture of amorphous TiO2 and rutile phase. DC electrical resistivity rho measured for temperatures ranging from 300 to 500 K exhibited a metallic-like behaviour (rho(473K) = 1.05 x 10(-5) to 1.45 x 10(-6) Omega m) with a temperature coefficient of resistance ranging from 1.20 x 10(-3) K-1 for the highest period (Lambda = 50.0 nm) down to negative values close to -4.97 x 10(-4) K-1 for the smallest one (Lambda = 14.0 nm). A relationship between the dimensions of periodic layers and their collective electrical resistivity is proposed where the resistivity does not solely depend on the total thickness of the film, but also depends on the chemical composition and thickness of each sub-layer. Charge carrier mobility and concentration measured by the Hall effect were both influenced by the dimension of TiO2/TiO/Ti periods and the density of ionized scattering centres connected to the titanium concentration in the metallic sub-layers. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

International audience; Thin films composed of titanium nitride doped with silver were deposited by DC reactive sputtering, with Ag contents varying between 0 and 50 at.%. The as-deposited samples were subjected to vacuum annealing treatments, with a range of temperatures varying from 200 to 500 °C, in order to study the morphological and structural changes that may occur. The as-deposited samples showed three main zones of basic characteristics, which differ both in terms of morphology and structural features. By increasing the annealing temperature, the thermodynamic stability is accelerated, giving rise to (i) a uniform dispersion of silver particles at 200 °C; (ii) the start of segregation at 300 °C; (iii) at 400 °C the coalescence of the segregated Ag particles takes place and finally (iv) at 500 °C the formation of large Ag clusters is evident, particularly within the zone that comprises the samples with higher Ag content. In addition to corroborate the presence of free Ag in Ag:TiN thin films, the increasing annealing temperature promotes the improvement of the coating's crystallinity, as well as Ag grain growth.

Direct current magnetron sputtering was used to produce AlNxOy thin films, using an aluminum target, argon and a mixture of N2+O2 (17:3) as reactive gases. The partial pressure of the reactive gas mixture was increased, maintaining the discharge current constant. Within the two identified regimes of the target (metallic and compound), four different tendencies for the deposition rate were found and a morphological evolution from columnar towards cauliflower-type, ending up as dense and featureless-type films. The structure was found to be Al-type (face centered cubic) and the structural characterization carried out by X-ray 2 diffraction and transmission electron microscopy suggested the formation of an aluminumbased polycrystalline phase dispersed in an amorphous aluminum oxide/nitride (or oxynitride) matrix. This type of structure, composition, morphology and grain size, were found to be strongly correlated with the electrical response of the films, which showed a gradual transition between metallic-like responses towards semiconducting and even insulating-type behaviors. A group of films with high aluminum content revealed a sharp decrease of the temperature coefficient of resistance (TCR) as the concentration ratio of non-metallic/aluminum atomic ratio increased. Another group of samples, where the non-metallic content became more important, revealed a smooth transition between positive and negative values of TCR. In order to test whether the oxynitride films have a unique behavior or simply a transition between the typical responses of aluminum and of those of the correspondent nitride and oxide, the electrical properties of the ternary oxynitride system were compared with AlNx and AlOy systems, prepared in similar conditions., This research is sponsored by FEDER funds through the program COMPETE-Programa Operacional Factores de Competitividade, by the national funds through FCT-Fundação para a Ciência e a Tecnologia, under the project PTDC/CTM-NAN/112574/2009 and Programa Pessoa 2010/2011 Cooperação Portugal/França, Proc.º 441.00, Project“COLOURCLUSTER”. J. Borges also acknowledges FCT financial support under PhD grant no. SFRH/BD/47118/2008.

International audience; DC reactive sputtering was used to deposit titanium and tungsten-based metal/oxide periodic nanometric multilayers using pure metallic targets and Ar + O-2 gas mixture as reactive atmosphere. The innovative technique namely, the reactive gas pulsing process allows switching between the metal and oxide to prepare a periodic multilayered structure with various metalloid concentrations and nanometric dimensions. The same pulsing period was used for each deposition to produce metal-oxide periodic alternations close to 10 nm. Structure, crystallinity and chemical composition of these films were systematically investigated by Raman spectroscopy, X-ray diffraction and Energy-dispersiveX-ray spectroscopy techniques. The high resolution transmission electron microscopy allowed observing the sharpness of the metal/oxide interfaces and measuring the thickness of each kind of layers. Moreover, the crystalline structure of metal and metal oxide layers was also studied. The difference of reactivity between the two systems leads to periodic beta-W3O/a-WO3 and face-centered-cubic-TiO/a-TiO2 multilayers.

Silicon oxynitride thin films were synthesised by the reactive gas pulsing process using an argon, oxygen and nitrogen gas mixture from a semiconductor Si target. Argon and nitrogen were introduced at a constant mass flow rate, whereas oxygen gas was periodically supplied using a rectangular pulsed flow rate. The O 2 injection time T ON (or duty cycle α ) was the only varied parameter. The influences of this parameter on the discharge behaviour, on the Si target voltage, and on the resulting chemical composition of the films were investigated. The temporal evolution of the total pressure exhibits exponential shape differing from the rectangular oxygen pulse shape, due to the response time of the gas flowmeter and to the progressive oxidation of the target and the chamber walls. During the T ON time, the preferential adsorption of the introduced O 2 induces a decay in Si target voltage. Reversion to the nitrided mode is still possible as soon as the O 2 injection is stopped. The elemental analyses assessed by secondary neutral mass spectrometry (SNMS) showed that the O/N ratio within silicon oxynitride films linearly depends on the T ON time. Increasing the duty cycle α over a certain value results in an oxidised steady state formation during the T ON time. This formation was observed by real time measurements of the emission lines ratio I (O * )/ I (Ar * ) indicative of the O 2 partial pressure and confirmed by the time derivative of the target voltage. During the T OFF time, the alternation with the nitrided mode becomes impossible, leading to the specific synthesis of stoichiometric SiO 2 films.

Monte Carlo simulations are developed to simulate the growth of three-dimensional columnar microstructure in thin films. We are studying in particular oriented microstructure like those produced with the Glancing Angle Deposition technique (GLAD) [1]. Some geometrical characteristics of the particles flux, the organization of defect sites on the substrate surface and the atomic surface diffusion are mainly investigated in order to predict the growth processes and the resulting features of the films. This study reports on simulations of thin film growth exhibiting an oblique and zigzag columnar microstructure. Column angle evolution and density are investigated versus incidence angle α or period number n and compared with experimental measurements.

Zirconium oxynitride thin films were deposited by dc reactive magnetron sputtering. A zirconium metallic target was sputtered in an Ar + N2 + O2 atmosphere. Argon and nitrogen flow rates were maintained constant whereas oxygen was pulsed during the deposition, implementing the reactive gas pulsing process (RGPP). A constant pulsing period T = 3 s was used following an exponential periodic signal versus time. The introduction time of oxygen was systematically changed from 17% to 83% of the period. The RGPP allowed the synthesis of ZrOxNy films with tuneable metalloid concentrations adjusting the introduction time of the oxygen. Composition and structural variations associated with mechanical, optical and electrical properties exhibited a smooth transition, from metallic-like characteristics, typical of the fcc-ZrN phase, to semi-conducting behaviour corresponding to a mixture of orthorhombic-Zr3N4(O) and γ -Zr2ON2 crystalline phases., Fundação para a Ciência e Tecnologia (FCT) - PTDC/CTM/69362/2006.

Nowadays, almost all the cutting tools in metal machining are protected with a surface treatment. Nevertheless, this is not the case in woodmachining where no tools are protected, except by thermal treatments, and so they present a previous wear because of the use of steel or carbide materials in milling, sawing, routing, etc. During these processes, the tools are particularly exposed to abrasive and shock wear. To enhance their wear resistance, one solution is to protect them with hard coatings. The present study deals with the development of ternary systems (CrAlN and CrSiN) obtained by two PVD different magnetron sputtering systems [‘A’ (laboratory where CrAlN layers have been obtained) and ‘B’ (laboratory where CrSiN layers have been obtained) in the following text] on carbide WC–Co tools used in second transformation of wood to be compared to the binary CrN one. CrAlN and CrSiN films were deposited with different Al and Si contents, respectively, in order to check the effect of the additive element (Al or Si) on the different properties of the Cr–N system. The different coatings were characterized by SEM and EDS for thickness measurements, morphology and composition analyses, respectively, by nanoindentation for hardness and Young’s modulus measurements and by pin-on-disc to determine their friction coefficient. Routing of medium density fibreboard (MDF) was realized employing untreated or modified carbide WC–Co tools in order to compare their wear resistance. We observed that the Al and the Si addition improved the hardness and the Young’s modulus of the Cr–N system (‘A’: 29 and 410 GPa, respectively, ‘B’: 18 and 280 GPa, respectively). Indeed, the hardness values are 15–36GPa for CrAlN and 15–24 GPa for CrSiN coatings. Besides, the Young’s modulus values are 331–520GPa for CrAlN and 260–320 GPa for CrSiN coatings. The friction coefficient of the CrAlN layers varied between 0.6 and 0.7 and it increased slightly with the Al content. For the CrSiN coatings, the friction coefficient was lower and about 0.4. In both cases, the CrN layers ‘A’ and ‘B’ presented similar friction coefficient than CrAlN and CrSiN, respectively. During the routing of MDF, the CrN ‘A’ coating has a similar wear behaviour than the optimized CrAlN one (5 at.% of Al) while the optimized CrSiN coating (1.2 at.% of Si) showed a better behaviour against wear than the CrN ‘B’ one. The wear resistance of CrAlN- and CrSiN-coated carbide tools ecreased when the Al and Si contents increased. Regional Council of Burgundy Regional Council of Franche-Comté ISOROY France

International audience; Thin films of titanium, copper and silver with various roughnesses were prepared by physical vapour deposition technique: dc magnetron sputtering. By varying the deposition time from few minutes to one hour it was possible to obtain metallic films with surface roughness average ranging from 1 to 20 nm. The wettability of these films was studied by measuring the contact angle using the sessile drop method and surface forces were investigated using the atomic force microscopy (AFM) by measuring the pull-off force between the AFM tip and the surfaces. Experimental results have been mainly discussed in terms of metal surface reactivity, Young modulus of the materials and real surface of contact between the AFM tip and the film surfaces.

Several chromium thin films with thicknesses comprised between 840 nm and 440 nm have been deposited by magnetron sputtering at glancing angle on silicon substrates. The deposition angle was varied between 0° and 80° resulting in nanosculptured thin films with column angles comprised between 0° and 25°. The surface topography of the films has been characterized by atomic force microscopy. It revealed different structurations of the surface originating from: the cross-section of the tilted columns with the surface, lateral ordering of the columns and faceting. The optical properties of the films have been determined from generalized ellipsometric measurements performed along different azimuths. The inspection of the off-diagonal elements of the Jones matrix as a function of columns tilt angle showed that both in-plane and out-of-plane anisotropy were present, associated with the columnar growth.

Titanium oxide thin films were prepared by reactive magnetron sputtering. The reactive gas pulsing process was implemented to control the oxygen injection in the deposition process and,consequently, to tune the oxygen concentration in the films from pure titanium to stoichiometric TiO2, maintaining a homogeneous in-depth concentration. The electrical conductivity of the films was investigated as a function of the oxygen injection time, the metalloid concentration and temperature, in the range 90–600 K. The curved Arrhenius plots of the conductivity were examined taking into account the grain boundary limited transport model of Werner J. H. Werner Solid State Phenom. 37–38, 213 1994 . The grain barrier heights were found to depend significantly on the oxygen supplied into the deposition process and thus, on the oxygen-to-titanium atomic ratio in the films. The analysis as a function of temperature showed that the conduction mechanism in the coatings was not solely limited by the oxygen-to-titanium atomic ratio, but also by the grain boundary scattering.

Glancing angle deposition (GLAD) was used to sculpt chromium thin films sputter deposited by dc magnetron sputtering into the desired zigzag microstructure. The flux angle of incident species α was systematically varied from 0 to 50° and periodically changed from α to − α . The total film thickness was kept constant at 1 μm and the number of periods ranged from 0.5 to 10. In order to improve the film adhesion, a substrate heating (350 °C) was added during the sputtering. Our results show that the zigzag microstructure of chromium thin films influences the microstructure and the surface properties of the coatings. The relationships between the Ra roughness, the flux angle and the number of periods were successfully demonstrated. This allows the deposition of films with controlled roughness. It was shown that the regularity of the surface morphology is improved for the flux angles α > 20°. Microstructure of the films was investigated by SEM, AFM and X-ray diffraction and the mechanical properties were determined by nanoindentation.

DC reactive sputtering was used to successfully make thin films of titanium oxynitride using titanium metallic target, argon as plasma gas and nitrogen and oxygen as reactive gases. The nitrogen partial pressure was kept constant during every deposition whereas oxygen flow rate was pulsed using a square pattern. The study consisted in analysing the influence of the shape of the pulsed rate on physical properties of these films. In order to adjust the metalloid concentration to get films with a wide range of oxygen-to-nitrogen ratios, the reactive gas pulsing process (RGPP) was used. In this process, the oxygen flow switches “on” and “off” periodically according to a duty cycle α = t ON / T . Electrical conductivity of films measured against temperature was gradually modified from metallic ( σ 300K = 4.42 × 10 4 S m −1 ) to semi-conducting behaviour ( σ 300K = 7.14 S m −1 ) with an increasing duty cycle. Mechanical properties like nanohardness ( H n ) and reduced Young's modulus ( E r ) of the films were investigated. Experimental values of H n and E r obtained by nanoindentation at 10% depth ranged from 15.8 to 5.2 GPa and from 273 to 142 GPa, respectively. Evolutions of H n and E against duty cycle were similar. A regular decrease was observed for duty cycle α ≤ 25% corresponding to the occurrence of TiO x N y phase. Higher duty cycles led to the smallest values of H n and E and correlated with TiO 2 compound composition. At last, the colour variation of these titanium oxynitrides was investigated as a function of α in the L * a * b * colour space. It was related to the chemical composition of the films.

Tungsten oxynitride films (W-O-N) were prepared by DC reactive magnetron sputtering in a wide range of compositions from tungsten nitride (WN) to tungsten oxide (WO3), by changing the oxygen and nitrogen flows, fO2 and fN2, respectively. The total pressure was 0.3 Pa and the (p?+?p)/pAr ratio was kept constant at 1:1. The coatings were characterized concerning the chemical composition, structure, electrical, and optical properties by electron probe microanalysis, X-ray diffraction, four-point probe, and ellipsometry, respectively. A linear increase in the oxygen content was observed as a function of the increasing O2 flux. The composition will influence the structure and the electrical and optical properties of the coatings.

TiCxOy films with various O/Ti ratios have been deposited by DC magnetron sputtering, using C pieces incrusted in a Ti target erosion area. Composition analysis revealed the existence of three different growth regimes: (i) zone I, corresponding to films with metallic-like appearance, and atomic ratios O/Ti below one; (ii) zone II, with films revealing interference-like colours, and atomic ratios O/Ti higher than 2. Between these two regions, there was a transition zone T, where the atomic ratio O/Ti is between one and two. The films within this zone revealed a brown colour. X-ray diffraction (XRD) structural characterization results showed an evolution from a mixed Ti(C,O) phase at lower O/Ti ratio, to a quasi-amorphous structure within zone T, and poorly crystallized rutile and anatase TiO2 at the highest O/Ti ratios (zone II). These different structural arrangements resulting from different film's compositions had clear effects on electrical resistivity, whose values increased from about 7 × 102 to 2 × 1011 [mu][Omega] cm with increase of the O/Ti ratio. Fourier-transform infrared spectroscopy (FTIR) was used to further confirm the different nature of films structure and, thus, to better understand their properties variation. The observed behaviour was found to be in straight correlation with those of XRD. http://www.sciencedirect.com/science/article/B6TW0-4KWK0WW-3/1/f0de0f5875ba8dd82aec3345e10bf933

Titanium oxynitride thin films have been deposited by low-pressure metalorganic chemical vapour deposition and reactive sputtering. The growth temperature for chemical vapour-deposited films and water vapour partial pressure for sputter-deposited films have been used to modulate the chemical composition. Both series have been analysed using X-ray photoelectron spectroscopy (XPS) in order to describe the structure of the materials using a factorial analysis approach. Titanium and metalloid concentrations have also been determined and compared to an elemental analysis performed using Rutherford backscattering spectroscopy and nuclear reaction analysis. The two deposition methods led to the synthesis of TiOxNy coatings exhibiting various oxygen and nitrogen concentrations from metallic TiN to insulating TiO2 compounds. Taking into account the Ti 2p signals of XPS spectra and implementing the factorial analysis, both series exhibited the coexistence of two phases, namely Ti(N,O) and TiO2. Quantification of each phase has been calculated and discussed as a function of the deposition conditions.