Studies on single layer CeO 2 and SiO 2 films deposited by rotating crucible electron beam evaporation

Abstract

High index CeO 2 films and low index SiO 2 films are widely used in multi layer optical thin film devices, such as high reflectors, interference filters, anti reflection coatings, etc. Optical properties, such as refractive index, transmittance in the UV, Visible and IR depends upon the deposition conditions, especially the substrate temperature. Single layer films of CeO 2 and SiO 2 have been deposited using a novel rotating crucible electron beam evaporation technique. The refractive indices and UV, VIS and IR transmittance of the films have been measured by varying substrate temperature in the range ambient to 400 °C. The structure of CeO 2 films has also been studied. The refractive index of CeO 2 films at 550 nm increased from 2.00 to 2.41 as the substrate temperature was increased from ambient to 400 °C. The extinction coefficient of these films was negligibly small even at elevated substrate temperatures. CeO 2 films deposited even at ambient temperature were crystalline. The refractive index of SiO 2 films increased marginally from 1.46 to 1.48. UV, Visible and IR transmission characteristics of SiO 2 films indicate that the films are stoichiometric. The density of CeO 2 and SiO 2 films has also been estimated with substrate temperature.