Effect of YF3 Coating Process on Film Stress

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.