Tungsten oxide WO₃ thin films are deposited by DC reactive magnetron sputtering. The Reactive Gas Pulsing Process (RGPP) associated with the GLancing Angle Deposition method (GLAD) are implemented to produce zigzag columnar structures. The oxygen injection time (t_ON time) and the pulsing period are kept constant. Three tilt angles α are used: 75, 80, and 85° and the number of zigzags N is progressively changed from N = 0.5, 1, 2, 4, 8 to 16. For each film, refractive index, extinction coefficient, and absorption coefficient are calculated from optical transmission spectra of the films measured in the visible region from wavelength values only. Absorption and extinction coefficients monotonously drop as the number of zigzags increases. Refractive indices are the lowest for the most grazing tilt angle α = 85°. The highest refractive index is nevertheless obtained for a number of zigzags close to four. This optimized optical property is directly correlated to changes of the microstructure, especially a porous architecture, which is favored for high tilt angles, and tunable as a function of the number of zigzags.

Tantalum oxide thin films are deposited by DC reactive magnetron sputtering from a tantalum metallic target and argon + oxygen. The oxygen gas is pulsed during the deposition with a constant pulsing period T = 10 s, whereas the introduction time of the reactive gas, namely the t_ON injection time, is systematically changed from 0 to 100% of T. Therefore, composition of as-deposited TaO_x films is continuously changed from pure metallic tantalum to the over-stoichiometric Ta₂O₅ material. Films adopt the body-centered cubic structure (metallic Ta) for the lowest t_ON injection time values (oxygen stoichiometry x < 1.0) and become amorphous for the longest ones. It is shown that the t_ON injection time is a key parameter to deposit either homogeneous tantalum oxides, or periodic Ta/TaO_x multilayers with alternations close to 3 nm. Optical transmittance in the visible region of the film/glass substrate system and electrical conductivity vs. temperature both exhibit a gradual evolution from metallic (σ_300K = 8.17 × 10⁵ S m⁻¹ with an opaque behavior) to semiconducting (σ_300K = 1.97 × 10³ S m⁻¹ with a semi-transparent transmittance) and finally to dielectric properties (σ_300K < 10⁻⁵ S m⁻¹ for interferential films) as a function of the oxygen concentration in the films.

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.

Des couches minces d’oxynitrures de titane ont été déposées par pulvérisation cathodique réactive à l’aide d’une cible de titane, d’argon comme gaz neutre et d’azote comme gaz réactif. Deux méthodes ont été employées pour l’apport d’oxygène comme autre gaz réactif dans le procédé : l’utilisation de vapeur d’eau et le contrôle par débit pulsé d’oxygène. L’étude de la variation des couleurs, dans l’espace CIEL*a*b*, des dépôts élaborés sur substrat de verre a été menée pour les deux méthodes d’élaboration. Il est apparu un comportement similaire de la luminosité pour les deux séries de dépôts. En effet, celle-ci reste constante pour les faibles quantités d’oxygène dans les couches puis augmente plus ou moins brusquement jusqu’à atteindre une valeur seuil de 85 environ pour les couches de type oxyde. Les couples de coordonnées (a*, b*) suivent une tendance continue seulement dans le cas des couches réalisées par pulses d’oxygène. Ces propriétés colorimétriques seront comparées à la composition chimique et à la structure cristallographique des films. Titanium oxynitride thin films were deposited by d.c. reactive sputtering with a titanium target, argon as inert gas and nitrogen as reactive gas. Two techniques were applied to feed oxygen as reactive gas in the process: the use of water vapour and the control by pulsed flow rate of oxygen. The study of the variation of colours in the CIEL*a*b* colour space of the coatings prepared on glass substrates was performed for both techniques. A similar behaviour of the brightness appeared for both sets of coatings. Indeed it remains constant for the weak oxygen contents in the coatings and increases more or less abruptly to reach a plateau around 85 for the oxide coatings. The (a*, b*) values exhibit a continuous behaviour only in the case of the pulsing oxygen technique. These colorimetric properties will be compared to the chemical composition and the crystallographic structure of the films.

Journal de Physique IV, Journal de Physique Archives représente une mine d informations facile à consulter sur la manière dont la physique a été publiée depuis 1872.