Extraction of Elastic Modulus and Hardness of the Soft Metallic Films on Hard Substrates by Nanoindentation
A simple method to extract the intrinsic mechanical properties of the soft metallic thin films on hard substrates by nanoindenation is presented. Utilizing the geometry relationship of residual impressions obtained by the SEM image and the cross-sectional profile, the pile up error in elastic modulus determination of soft thin films by the Oliver and Pharr analysis is first corrected. Knowledge of the ‘true’ elastic modulus, the ‘true’ hardness of thin film is then extracted from the measured contact stiffness data for an elastically homogeneous film-substrate system. The present method is applied for a 504 nm Au thin film sputter deposited on the glass substrate and the results show that the ‘true’ elastic modulus and hardness of Au film are 80 GPa and 1.3 GPa, which are in agreement well with the literatures.