Eur. Phys. J. Plus (2016) 131: 187
https://doi.org/10.1140/epjp/i2016-16187-2

Regular Article

Mechanical properties of Ta-Al-N thin films deposited by cylindrical DC magnetron sputtering: Influence of N₂% in the gas mixture

Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran, Iran

^* e-mail: e.darabi@srbiau.ac.ir

Received: 22 June 2015
Accepted: 9 May 2016
Published online: 6 June 2016

Abstract

Ta-Al-N thin films were deposited by cylindrical DC magnetron sputtering on a stainless steel substrate under varying nitrogen flow ratios ( N₂ with respect to N₂ + Ar in the range of 1.5%-9%. The effect of the N₂ content in the reactive gas mixture on crystalline structure, surface morphology, and mechanical properties of Ta-Al-N thin films was investigated. The amount of Al and Ta in deposited films was obtained by energy dispersive X-ray spectroscopy (EDX) analysis and films thickness was measured by surface step profilometer. X-ray diffraction analysis (XRD) revealed that the crystalline structure of the Ta-Al-N polycrystalline thin film is a mixture of TaAl, TaN, and AlN crystalline phases. Surface morphology, roughness, and grain size were investigated by atomic force microscopy (AFM). The nano hardness of Ta-Al-N thin films, measured by the nanoindentation method, was about 9GPa maximum for samples prepared under 3% N₂ , and the friction coefficient, obtained by nanoscratch analysis, was approximately 0.2 for all Ta-Al-N thin films. Other results were found to be affected considerably by increasing the N₂ amount.