Structural and mechanical properties of a-C:H thin films grown by RF-PECVD

Laboratoire des Matériaux Inorganiques, UMR CNRS 6002, Université Blaise Pascal (Clermont-Ferrand 2), 24 Av des Landais, 63177 Aubière cedex, France
Diamond and Related Materials (Impact Factor: 1.92). 09/2004; 13(9):1618-1624. DOI: 10.1016/j.diamond.2004.01.017


a-C:H thin films have been deposited by plasma enhanced chemical vapor deposition at 13.56 MHz in a large bias voltage range (200–600 V). Their mechanical properties have been studied through different techniques such as nanoindentation, profilometry and finally X-ray reflectometry in order to determine their hardness, elastic modulus, stress level, interfacial fracture energy and density. We show that the hardness, the Young modulus, the density and the stress level decrease with increasing bias voltage contrary to the interfacial fracture energy, hence the adhesion of the deposits. To understand this behavior, films microstructure has been characterized through the determination of hydrogen and sp3 hybridized carbon contents by ERDA, FTIR, Raman diffusion and ESR. We have demonstrated that a graphitization and a loss of hydrogen occur when the bias increases. Such evolutions are explained in terms of the subplantation model proposed by Lifshitz. Finally, hard and dense coatings can be grown at low bias as the sp3 carbon content is high, but their corresponding adhesion is low.

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Available from: Laurent Thomas, May 07, 2015
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    • "However, despite these advantages, the deposition of a-C:H coatings is a complicated process and depends on many different factors [4] [5] [6] [7]. * Results presented at the international conference Radiation Interaction with Material and Its Use in Technologies 2008, 24–27 September 2008, Kaunas, Lithuania Many authors [4] [5] [6] [7] [8] [9] [10] [11] [12] have demonstrated that the hydrogen concentration and corresponding proportion of the sp 2 and sp 3 carbon sites in the films determines the properties of carbon coatings. Variation of the deposition process parameters allows one to control and produce a-C:H films with desirable properties. "
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