Stress reduction by ion bombardment in CeO2 films

We have investigated the influence of deposition parameters on film stress in CeO2 films grown on biaxially textured nickel (001) substrates using pulsed-laser deposition. The film stress is thought to consist of thermal stress and intrinsic stress. The thermal stress has been calculated at different deposition temperatures. The results reveal that the thermal stress is compressive with MPa order of magnitude and increases with increasing deposition temperature. The intrinsic stress has also been measured by standard X-ray diffraction technique. It has been found that the intrinsic stress is tensile with GPa order of magnitude, and decreases with increasing deposition temperature regardless of whether the films are deposited with ion bombardment or not. Moreover, this is the first time a quantitative confirmation of stress reduction with ion bombardment has been provided. Some possible origins of the influence of deposition parameters on film stress are discussed.