Structure and Tribological Properties of Ultra-Thin Tetrahedral Amorphous Carbon (ta-C) Films

Ultra-thin tetrahedral amorphous carbon (ta-C) films were deposited by the filtered cathodic vacuum arc (FCVA) technique. The thickness, structure, and topography of the films were studied by various analysis methods, such as auger electron spectroscopy (AES) depth profile, high resolution transmission electron microscope (HRTEM), Raman spectroscopy, and atomic force microscopy (AFM). A tribometer was used to investigate the tribological properties of the ta-C films. The results indicate that ta-C film with thickness less than 2 nm can be obtained by the FCVA technique. As the film thickness increases the relative intensity ratio ID/IG decreases, which means that sp3 bond in the films increases. The oxide layer cleaning procedure of silicon substrate before deposition influences the growth mode and surface roughness of the films. The ultra-thin ta-C film has the lowest friction coefficient of 0.19 and excellent anti-wear properties.