Effects of low substrate temperature and ion assisted deposition on composition, optical properties, and stress of ZnS thin films

ZnS thin films were deposited with and without ion assisted deposition onto substrates held at temperatures ranging from -120 to 50 degrees C. Effects on chemical and crystalline composition, film microstructure, refractive index, stress, and waveguide losses were investigated. We observed that minimum stress and minimum losses occurred at the same deposition temperature (-50 degrees C) in ZnS films, which also corresponded to a quenching of crystallinity.