Optical properties and residual stress of YbF_3 thin films deposited at different temperatures

The influence of deposition temperature on the optical properties, microstructure, and residual stress of YbF3 films, deposited by electron-beam evaporation, has been investigated. The increased refractive indices and surface roughness of YbF3 films indicate that the film density and columnar structure size increase with deposition temperature. At the same time, higher packing density reduces absorption of moisture. The residual stress is related to deposition temperature and to substrate. For the samples deposited on BK7, the residual stress mainly comes from intrinsic stress, however, for those on fused silica, thermal stress is the dominant factor of total residual stress.