Ion beam energy effects on structure and properties of SiO x doped diamond-like carbon films Š. Meškinis a,b, ⁎ , R. Gudaitis a , K. Šlapikas a , S. Tamulevičius a,c , M. Andrulevičius a , A. Guobienė a,b , J. Puišo a,c , G. Niaura d a Institute of Physical Electronics of Kaunas University of Technology, Savanorių 271, LT-50131 Kaunas, Lithuania b International Studies Centre, Kaunas University of Technology, A. Mickevičiaus 37, LT-44244 Kaunas, Lithuania c Department of Physics, Kaunas University of Technology, Studentų 50, LT-51368 Kaunas, Lithuania d Institute of Chemistry, A. Goštauto 9, LT-01108 Vilnius, Lithuania Available online 30 August 2007 Abstract SiO x doped diamond-like carbon (DLC) films were synthesized by direct ion beam from hexamethyldisiloxane vapor. Effects of ion beam energy were studied. Variation of atomic concentration of the oxygen versus carbon with ion energy has been observed. Raman scattering spectroscopy didn’t indicate essential changes in structure of the films deposited at different ion beam energies. The synthesized films were atomically smooth. Depending on the ion energy the refractive index of the SiO x doped diamond-like carbon films varied within 2.1–2.5 and increased with increase of energy. The contact angle with water for all samples was only 61–64°. © 2007 Elsevier B.V. All rights reserved. Keywords: SiO x doped diamond-like carbon; Ion energy; XPS; Raman scattering spectra; AFM; Contact angle with water 1. Introduction Diamond-like carbon films remain at the top of a huge interest due to their exceptional properties [1]. In particular, advantages of the SiO x doped DLC films over “conventional” hydrogenated DLC films in reduction of the internal stress [2] and friction coefficient [3], better adhesion with different metallic substrates [4], higher wear resistance [3], higher optical transmittance [5], higher thermal stability [6] and increased hydrophobicity [7] were reported. These coatings offer a promising solution for many industrial applications [3]. Ion bombardment during film growth is a necessary part of the diamond-like carbon synthesis process because sp 3 bonding in ion beam based techniques is due to the subplantation (low energy subsurface implantation) process, where ion energy plays an essential role defining structure and properties of DLC [1]. However, there are only few studies on the effects of the ion energy on the structure, chemical composition and properties of SiO x doped DLC films. In the present research effects of the ion energy on structure and chemical composition of SiO x containing diamond-like carbon films were investigated. Morphology and hydrophobic properties of the synthesized films have been studied. 2. Experimental SiO x doped DLC films were deposited on Si(100) substrates at room temperature using a closed drift direct current ion source. Hexamethyldisiloxane (C 6 H 18 Si 2 O) vapor has been used as a hydrocarbon, silicon and oxygen source. Hexamethyldisiloxane vapor was introduced into the chamber using a Bronkhorst liquid delivery system with a Controlled Evaporator Mixer W-102A- 122-K. The base pressure was (2· 10 - 4 ) Pa, work pressure — (1÷2)·10 - 2 Pa. 300, 400, 600 and 800 eVenergy ion beams have been used for the synthesis of films. The thickness of the synthesized films was 100–400 nm. X-ray Photoelectron spectra were recorded with a KRATOS ANALYTICAL XSAM800 XPS analyser. Al K α radiation (hν =1486.6 eV) was used. The energy scale of the system was determined according to Au4f 7/2 peak, the analyser being in the Available online at www.sciencedirect.com Surface & Coatings Technology 202 (2008) 2328 – 2331 www.elsevier.com/locate/surfcoat ⁎ Corresponding author. Institute of Physical Electronics of Kaunas University of Technology, Savanorių 271, LT-50131 Kaunas, Lithuania. Tel.: +370 37 327605; fax: +370 37 314423. E-mail address: sarunas.meskinis@fei.lt (Š. Meškinis). 0257-8972/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.surfcoat.2007.08.035