Annealing of intrinsic stresses in sputtered TiN films: The role of thickness-dependent gradients of point defect density

Morphology, structure and thermal behavior of magnetron sputtered TiN thin films with the thickness in the range 100-2900 nm are characterized. The films are thermally cycled and the relationship between film thickness, defect density and the intrinsic stress relaxation is analyzed. The results indicate that the residual stresses in the as-deposited films and the amount of stress relaxation depend decisively on the specific depth gradient of point defects originating from film evolution during growth. The compressive stresses, representing different driving forces and the amount of stress relaxation decrease, while the onset temperature of stress relaxation increases with increasing film thickness.