Synthesis of CeO2 films by ion beam assisted deposition

Cerium oxide (CeO₂) films were prepared by ion beam assisted deposition(IBAD). The films were synthesized on Si wafers by depositing CeO₂ vapor under simultaneous bombardment with oxygen ions in the energy range of 1.0-4.0 keV. Film characterizations were performed by X-ray diffractometry for structural analysis, Rutherford backscattering spectrometry for film composition and the packing density measurements, ellipsometry for refractive index measurements and field-emission type scanning electron microscopy for cross sectional observation of film morphology. With increasing ion energy and/or ion-to-CeO₂ vapor transport ratio, film crystallization was enhanced; preferential orientation shifted from (111) to (220), and the morphology changed from the columnar grains to the granular. The increase in the transport ratio (O⁺/CeO₂) also revealed significant enhancement on the film packing density, leading to the increase in the refractive index