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.