Femtosecond pulsed laser deposition of CeO2 thin films on silicon (100) substrates

Cerium oxide (CeO2) thin film was successfully deposited on silicon (100) via femtosecond pulsed laser deposition (fs-PLD). The deposition was carried out at varying deposition pressure at ambient temperature. The absence of defined CeO2 peaks in the X-ray diffraction (XRD) spectra for as-deposited samples imply that the film is amorphous. All the films show the circular colored fringes due to thin-film interference. The pattern indicates that a radial variation in film thickness caused by the distribution of the ablated material in the plasma plume. The laser-produced plasma evolving pattern caused this variation. Comparison of the as-deposited samples thicknesses were done via reflectance spectroscopy. Background gas pressure affects the deposition rate of the grown film. One sample was post-annealed at 1000°C for 2 hours to improve the thickness uniformity and crystal structure. The XRD spectra of this film shows an enhancement in its crystallinity. Five peaks attributed to CeO2 crystal phase indicate the cubic structure of the film.