Surface topography and nanomechanical/tribological behaviour of ultrathin nitride films on silicon

Surface topography and roughness characteristics were studied based on the analysis of three dimensional atomic force microscopy images of several multilayer ultrathin-film samples. TiN, CrN and NbN (200 nm thick) were deposited on single crystal n-type silicon without or with a 200 nm thick underlayer of silicon dioxide or silicon nitride. The nitride films were deposited by physical vapour deposition technique and the underlayer films by plasma-enhanced chemical vapour deposition. Nanomechanical studies and nanotribological tests were also conducted to investigate the properties of such films as possible candidates for protective layers on rubbing elements of micro-electromechanical systems. The effect of the underlayer on the surface properties and the mechanical/tribological behaviour was evaluated as well.