Tribological performance of ultrathin diamond-like carbon films prepared by plasma-based ion implantation

Abstract

Ultrathin diamond-like carbon (DLC) films with thicknesses of 5–60 nm have been prepared on Si by plasma-based ion implantation. Raman spectrum and x-ray photoelectron spectroscopy (XPS) show that these DLC films present high sp3/sp2 ratios. XPS also displays that each DLC film firmly adheres to the Si substrate owing to a C–Si transition layer. Atomic force microscopy shows that the DLC films are smooth and compact with average roughness (Ra) of about 0.25 nm. Sliding friction experiments reveal that these DLC films show significantly improved tribological performance. With increase of DLC film thickness, the sp3/sp2 ratio increases, the roughness decreases, the hardness increases, the adhesive wear lightens and thereby the tribological performance becomes enhanced. Also, the effects of the applied load and the reciprocating frequency on the tribological performance are discussed.

Failure mechanism and protective role of ultrathin ta-C films on Si (100) during cyclic nano-impact

“…For example, as protective coatings in silicon-based microelectromechanical system (MEMS) technology in which the relatively high brittleness and low fracture toughness at room temperature restrict their reliability under mechanical stress [6][7][8]. Another important application of DLC films is to act as overcoats for heads and magnetic media in hard disk and tape drive systems where the protective layers should be resistant to wear and corrosion, but thin enough not to impede the high density recording capability [9][10][11][12]. In both cases, film thickness is usually in the range from 2-100 nm.…”