Mixtures of acetylene/argon and methane/argon with different volume percents of hydrocarbon were used as the precursor gas to grow DLC films, keeping constant the other process parameters. The substrates used were p-type (100) silicon wafers. The films were characterized by Raman spectroscopy, nanoindentation, atomic force microscopy (AFM) and by a profilometer. In order to grow DLC films with special properties that could make this material an alternative candidate for applications in microelectromechanical systems (MEMS) production, a comparative analysis focused on the influence of the hydrocarbon precursor gas mixture on the mechanical and chemical properties of the DLC films is reported. (C) 2003 Elsevier B.V. All rights reserved.