Nano-hardness estimation by means of Ar+ ion etching

•ZnO film and Carbon films were grown on silicon using PVD.•The growth temperature was room temperature.•The hardness of the coatings was estimated by means of nanoindentation.•Evaluation of resistance of materials to the mechanical damage induced by an Ar+ ion gun (AES).•The hardness have been studied and a power law with the erosion rate has been found.

When the coatings are in nano-scale, the mechanical properties cannot be easily estimated by means of the conventional methods due to: tip shape, instrument resolution, roughness, and substrate effect. In this paper, we proposed a semi-empirical method to evaluate the mechanical properties of thin films based on the sputtering rate induced by bombardment of Ar+ ion. The Ar+ ion bombardment was induced by ion gun implemented in Auger electron spectroscopy (AES). This procedure has been applied on a series of coatings with different structure (carbon films) and a series of coating with a different density (ZnO thin films). The coatings were deposited on Silicon substrates by RF sputtering plasma. The results show that, as predicted by Insepov et al., there is a correlation between hardness and sputtering rate. Using reference materials and a simple power law equation the estimation of the nano-hardness using an Ar+ beam is possible.