Post-deposition reduction of internal stress in thin films: The case of HfN coatings bombarded with Au ions

Abstract

Abstract The post-deposition bombardment of reactively sputtered HfN thin films with energetic (1, 2.5 and 5 MeV) gold ions to a fluence of 10 14 cm −2 resulted in a considerable reduction of high internal stresses which were estimated from the measurements of the surface curvature. The higher the energy of the gold species the lower degree of relaxation was registered. The observed phenomena are attributed here to the transport of the interstitial defects within the thermal spikes induced by bombarding HfN with Au ions. An alternative explanation of stress-reduction caused by an increase in vacancy concentration is also presented. Significant softening of HfN films after ion-beam treatment was registered by the high accuracy depth-sensing indentation method and attributed to the formation of an inter-layer of amorphous silicon, directly under the film. A structural analysis has been carried out using thin film X-ray diffraction. Nitride film resistivity was found to be slightly enhanced by bombardment with Au ions.