Effects of ion-beam-irradiation on morphology and densification of CeO2 films prepared by ion-beam-assisted deposition

Cerium oxide (CeO2) films were prepared by ion-beam-assisted deposition (IB AD). The films were synthesized on Si wafers by depositing CeO2 vapor under simultaneous bombardment with O-2, Ar and Xe ions in the energy range of 1 .0 to 5.0 keV. Film characterizations were performed using field-emission-t ype scanning electron microscopy (FE-SEM) for cross-sectional observation o f film morphology and film crystallization was examined by X-ray diffractom etry (XRD). Rutherford backscattering spectrometry (RBS) was used for measu ring the film composition and the packing density. Refractive indices of th e films were measured by ellipsometry to investigate their optical properti es. With increasing the transport rate ratio of ions to CeO2 vapor, the mor phology of the specimens prepared with O-2 and Xe ion beams was changed fro m columnar to granular structure. The increase in the transport ratio also had a significant effect on the enhancement of the film densification, lead ing to an increase in the refractive index.