Structural and tribological properties of diamond-like nanocomposite thin films

The structural and tribological properties of diamond-like nanocomposite (DLN) thin films, deposited by radio frequency plasma enhanced chemical vapor deposition (rf-PECVD) on the pyrex glass or silicon substrate using the combinations of siloxane and silazane based gas precursors, are discussed. High resolution transmission electron microscopy (HRTEM) result shows the DLN film structure with different nanoparticle size. The surface morphology of the DLN films has been investigated by using atomic force microscopy (AFM). The structural properties of the DLN films are analyzed by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). We have observed different bonds like C―C, C―H, C―Si, C―O, Si―O, Si―H, etc. in the DLN films by XPS and FTIR analysis, which reveal that it consists of a-C:H and a-Si:O networks. The disorder and graphitic structure of amorphous carbon of the deposited films are analyzed by Raman spectroscopy. The hardness and friction coefficient of the films are measured by nanoindentation and scratch test techniques. Finally, we find that mixed siloxane and silazane precursor (MSSP) based DLN films provide better film-properties like surface roughness, friction coefficient, etc. than those of single siloxane or silazane precursor (SSSP) based DLN films.