Effect of YF3 Coating Process on Film Stress

Abstract

YF₃ rare-earth fluoride coating material has received wide attention as an alternative to ThF₄ low refractive index material, but the film layer can be seriously affected due to the different coating processes. Therefore, to investigate the rules between the coating processes of YF₃ rare-earth fluoride coating materials, YF₃ thin films were coated with different deposition rates and substrate temperatures. The stresses of YF₃ thin films under different processes were obtained by a thin film stress meter, and the microscopic morphology of the thin films was characterized by atomic force microscopy. The results show that: YF₃ monolayer film is tensile stress; in the deposition rate between 0.5nm/s~1.5nm/s, with the increase of the coating deposition rate YF₃ monolayer film stress tends to decrease, the roughness of the film is also gradually increased, and the overall thickness of the film surface decreases; in the substrate temperature is greater than 50 ℃, the film stress is significantly reduced.