Electrical resistivity and elastic wave propagation anisotropy in glancing angle deposited tungsten and gold thin films

Beainou, Raya El; Chargui, Asma; Pedrosa, Paulo; Mosset, A.; Euphrasie, Sébastien; Vairac, Pascal; Martin, Nicolas

doi:10.1016/j.apsusc.2019.01.041

Cited by 25 publications

(23 citation statements)

References 53 publications

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“…Due to the rather circular shape of the column cross-sections, x and y-velocities were similar with v x = 1800 m s −1 and v y = 2000 m s −1, which means an anisotropy A v around 1.2. These results are consistent with an earlier publication where no anisotropy on the pseudo-Rayleigh waves propagating in gold films deposited by GLAD are reported (SEM observations similarly showed nearly circular column cross-sections) [46].…”

Section: Elastic Wave Propagationsupporting

confidence: 93%

“…This anisotropic behavior, which was more obvious for thicknesses higher than a few hundred nm, agrees with other studies focused on the electronic transport properties of GLAD thin films [45]. Such behavior is mainly assigned to the elliptical shape of the columnar cross-section (fanning mechanism during the growth, as shown in Figure 2), being especially prominent in W GLAD thin films [46]. An alternation of dense and voided architecture is rather produced in the direction of the particle flux, whereas dense and chained columns were obtained following the normal direction.…”

Section: Electrical Resistivitysupporting

confidence: 91%

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Influence of Thickness and Sputtering Pressure on Electrical Resistivity and Elastic Wave Propagation in Oriented Columnar Tungsten Thin Films

et al. 2020

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Tungsten films were prepared by DC magnetron sputtering using glancing angle deposition with a constant deposition angle α = 80°. A first series of films was obtained at a constant pressure of 4.0 × 10−3 mbar with the films’ 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 × 10−3 to 15 × 10−3 mbar. The A15 β phase exhibiting a poor crystallinity was favored at high pressure and for the thinner films, whereas the bcc α 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.

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Section: Elastic Wave Propagationsupporting

confidence: 93%

Section: Electrical Resistivitysupporting

confidence: 91%

Influence of Thickness and Sputtering Pressure on Electrical Resistivity and Elastic Wave Propagation in Oriented Columnar Tungsten Thin Films

et al. 2020

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“…hardness, elastic modulus, etc. [37][38][39]. While two of these regimes have been characterized in terms of atomistic processes, we have demonstrated that the third one is associated to the presence of an intense plasma.…”

Section: Resultsmentioning

confidence: 75%

Kinetic energy-induced growth regimes of nanocolumnar Ti thin films deposited by evaporation and magnetron sputtering

et al. 2019

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We experimentally analyze different growth regimes of Ti thin films associated to the existence of kinetic energy-induced relaxation mechanisms in the material's network when operating at oblique geometries. For this purpose, we have deposited different films by evaporation and magnetron sputtering under similar geometrical arrangements and at low temperatures. With the help of a well-established growth model we have found three different growth regimes: i) low energy deposition, exemplified by the evaporation technique, carried out by species with typical energies in the thermal range, where the morphology and density of the film can be explained by solely considering surface shadowing processes, ii) magnetron sputtering under weak plasma conditions, where the film growth is mediated by surface shadowing mechanisms and kinetic-energy relaxation processes, and iii) magnetron sputtering under intense plasma conditions, where the film growth is highly influenced by the plasma, and whose morphology is defined by nanocolumns with similar tilt than evaporated films, but with much higher density. The existence of these three regimes explains the disparity of morphologies of nanocolumnar Ti thin films grown at oblique angles under similar conditions in the literature.

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“…The formed columns are titled toward the incident flux direction and can be sculptured into different morphologies, such as helices, inclined and vertical pillars (with variable diameter), zig-zags, and square spirals [49][50][51][52][53]. All these efforts make the GLAD technique excellent for design and device optimization for the development of sensors and optical devices, among others [45,[54][55][56][57][58].…”

Section: Introductionmentioning

confidence: 99%

Antifungal activity of ZnO thin films prepared by glancing angle deposition

et al. 2019

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Highlights• Zinc Oxide thin films were deposited by reactive magnetron sputtering;• Inclined columns changed the thin films' surface porosity;• Sputtering incidence angle affects microstructure and antifungal properties;• Mesoporous thin films improved the antifungal properties against Candida albicans; ABSTRACTThin films of zinc oxide (ZnO) were produced by reactive DC magnetron sputtering with sputtering angles of α = 0º, 40º, 60º and 80º (glancing angle deposition configuration), aiming to be tested against the opportunist pathogenic fungus Candida albicans. The results showed the formation of stoichiometric ZnO thin films, with inclined columns for incidence angles equal to or more than 40º. All thin films presented high transparency in the visible range above the bandgap region (near 380 nm). The deposition conditions gave rise to a three-fold increase of the surface porosity with the increment of the incidence angle. Noteworthy, is the formation of different types of pores distributions, from micro-, through meso-, to macropores. Regarding the biological effect, the thin films produced with inclined columns presented a significant antifungal activity, with the inhibition of viable cell growth by 68 %. Moreover, the formation of mesoporous films enhanced the antifungal properties of ZnO thin films against Candida albicans. The overall behaviour indicates that these thin films are promising candidates to be applied in antimicrobial surfaces, as well as to be used in further studies to determine the molecular mechanisms involved in the antimicrobial action of ZnO.3

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Electrical resistivity and elastic wave propagation anisotropy in glancing angle deposited tungsten and gold thin films

Cited by 25 publications

References 53 publications

Influence of Thickness and Sputtering Pressure on Electrical Resistivity and Elastic Wave Propagation in Oriented Columnar Tungsten Thin Films

Influence of Thickness and Sputtering Pressure on Electrical Resistivity and Elastic Wave Propagation in Oriented Columnar Tungsten Thin Films

Kinetic energy-induced growth regimes of nanocolumnar Ti thin films deposited by evaporation and magnetron sputtering

Antifungal activity of ZnO thin films prepared by glancing angle deposition

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