On the existence of point defects in physical vapor deposited films of TiN, ZrN, and HfN

Sets of experimental data from a number of different techniques are summarized in the present work. They indicate that lattice defects in the form of vacancies and interstitials are very often present in films of the group-IVB nitrides as prepared by plasma enhanced physical vapor deposition methods. Lattice parameters, even allowing for the presence of residual stresses, density and positron annihilation data and the effect of deposition conditions on the reflectance and color of films, together with the effects of tempering, indicate that the fraction of interstitials increases with the energy input into the growing film. Vacancies always appear to be present. Interstitials can be retained after tempering, possibly as extrinsic dislocation loops, and vacancy clusters are formed. X-ray photoelectron spectroscopy spectra appear to be affected by such lattice defects but the understanding of the spectral effects is not sufficiently advanced to allow even a qualitative interpretation.