Evolution of physical properties in hafnium carbonitride thin films

Abstract

Hafnium carbonitride coatings were deposited onto silicon substrates by reactive r.f. magnetron co-sputtering from hafnium and carbon targets in a reactive nitrogen atmosphere, varying applied negative bias voltages (0, −50, −100, and −150 V). The effect of the applied bias voltage on the crystalline structure, chemical composition, and mechanical properties was observed via X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, and nanoindentation techniques. The results show that the samples present constant stoichiometric ratio, Hf/(C+N), exhibiting improved mechanical properties by increasing negative bias voltage from 17 to 32 GPa for the hardness and from 200 to 280 GPa for elastic modulus. Therefore, the HfCN coatings can be used as future hard coating materials.