Film thickness effect on texture and residual stress sign transition in sputtered TiN thin films

Residual stress in thin films and coatings strongly affects their properties and behavior in service. Comprehensive understanding and precise measurements of residual stress are prerequisites for preparing high quality films and coatings. Residual stresses in TiN films with different thickness were measured by X-ray diffraction (XRD) employing the cos2α sin2ψ method with certain optimization. Grazing incidence parallel beam optics was combined with side-inclination geometry using in-house designed sample stage to ensure results accuracy. To validate this method, TiN films with thickness ranging from 1 to 3 µm were deposited on (100) Si single crystal substrates at 300 °C by RF magnetron sputtering. High compressive −2 GPa residual stress was present in the 0.9 µm thick film and decreased with film thickness. Tensile stress of less than 0.3 GPa was present in 2 µm TiN film. Compressive-to-tensile residual stress transition was observed with the film thickness increase. Microstructure change with growth, annihilation of grain boudaries, atomic peening and recovery mechanisms are responsible for the reported stress sign transition.