In Situ RHEED Observation of CeO₂ Film Growth on Si by Laser Ablation Deposition in Ultrahigh-Vacuum

Abstract

In a newly developed ultrahigh-vacuum (UHV) film preparation system equipped with in situ reflection high-energy electron diffraction (RHEED) and X-ray photoelectron spectrometer (XPS) analyzer, a sintered CeO 2 target was ablated by ArF excimer laser to deposit films on Si(001), (111) and (110) substrates at temperatures ranging from 600 to 700°C. Tetravalence of the Ce in the films was confirmed by XPS, indicating that stoichiometric CeO 2 was formed even in the UHV (≤10 -6 Torr) condition. The orientation of deposited CeO 2 films was strongly dependent on the surface state of Si substrates. The results are well explained in terms of preferential arrangement of the first plane of growing CeO 2 by its interaction with substrate surface.