Microstructure, Stress and Texture in Sputter Deposited TiN Thin Films: Effect of Substrate Bias

Abstract

Titanium nitride thin films deposited by reactive dc magnetron sputtering under various substrate bias voltages have been investigated by X-ray diffraction. TiN thin films exhibits lattice parameter anisotropy for all bias voltages. Preferential entrapment of argon atoms in TiN lattice has been identified as the major cause of lattice parameter anisotropy. Bombardment of argon ions during film growth has produced stacking faults on {111} planes of TiN crystal. Stacking fault probability increases with increasing substrate bias voltages. X-ray diffraction line profile analysis indicates strain anisotropy in TiN thin films. Diffraction stress analysis by d-sin2ψ method reveals pronounced curvature in the plot of inter-planar spacing (d) (or corresponding lattice parameter (a)) versus sin2ψ. Direction dependent elastic grain interaction has been considered as possible source of the observed anisotropic line broadening.