Energy Dissipation in Al/TiN Double Layered Films by Nano-indentation

An energetic approach in nano-indentation process using a Berkovich type indenter was applied to the evaluation of mechanical properties of thin films. Double layered Al/TiN films were deposited onto glass substrates by dc-magnetron sputtering apparatus. Thickness of the TiN upper layer was 500 nm, while that of Al bottom layer varied from 0 to 500 nm. The deformation energy caused by the indentation was obtained from the area of load-displacement curves indicated during the nano-indentation process. The deformation energy of the thin films was divided into elastic and plastic components. The elastic energy of the films showed constant values at each indentation load. Dissipated energy, however, increased with increasing Al thickness. This result suggests that the elastic deformation mainly takes place in the TiN layer and the plastic deformation does in the Al layer.