Effect of nitrogen flow ratio on nano-mechanical properties of tantalum nitride thin film

In this research, nanostructured tantalum nitride (TaN) thin films were deposited on 316L stainless steel substrates by reactive magnetron sputtering. The effect of nitrogen flow ratio (N2/(Ar + N2)) on the structural, mechanical and surface properties of deposited films was studied by means of XRD, SEM, Nano-indentation and AFM. The results revealed a strong correlation between the crystal structure and properties of TaN film, where the deposited film transforms from hexagonal γ-Ta2N to hexagonal ε-TaN and cubic TaN with increasing nitrogen flow ratio from 10% to 25%. In addition, it was found that increasing the nitrogen flow ratio will result in the target poisoning and lower the deposition rate, which causes the grains growth and roughening of the surface.