Fluorine-doped amorphous carbon (a-C:F). films were deposited using a 90 degrees-bend magnetic. filtered cathodic arc plasma system with CF4 as a precursor and the addition of argon gas. The microstructure, composition and chemical bonding nature of the a-C:F. films were investigated by Raman scattering spectroscopy and X-ray photoelectron spectroscopy. The surface morphology and roughness of a-C:F. films were observed through an atomic force microscope. Hardness was measured by nano-indentation. Water contact angles were measured by the sessile drop method. The. fluorine content of the. films increases with the argon. flux. Because of the increase of the. fluorine content in the. films, the. film surface becomes rougher; the hardness decreases, and the contact angle increases from 76.2 degrees to 87.8 degrees. This work demonstrates that an appropriate amount of the admitted argon to the plasma would promote the doping of the. films with. fluorine, and influences the properties of the a-C:F. films. (C) 2008 Elsevier B. V. All rights reserved.