A Study on the Surface of RF Magnetron Sputtered CeO₂ Thin Films at Relatively Low Substrate Temperature

Abstract

Influences of substrate temperature on crystal structure, surface topography and surface morphology of cerium dioxide or ceria (CeO2) thin films deposited using radio frequency (RF) magnetron sputtering were studied. The substrate temperature was varied i.e. room temperature, 100, 200 and 300 °C. The characteristics of the film surface could be controlled by tuning the substrate temperature. As studied in the X-ray diffraction (XRD) analysis, the CeO2 thin films exhibited a cubic fluorite structure with predominant (200) orientation at substrate temperature of room temperature and 200 °C, while (111) preferred orientation at substrate temperature of 100 and 300 °C. The CeO2 films featured uniform surface topography and surface morphology, as observed from the atomic force microscopy and scanning electron microscopy analyses, respectively. The surface roughness and the average grain size of the films fluctuated with increasing substrate temperature. This phenomenon was suggested due to the difference in the preferential orientation of the films as in the XRD analysis.