Controlling factors for the conversion of trifluoroacetate sols into thin metal fluoride coatings

Metal fluoride films were prepared from trifluoroacetate sols by a spin-coa ting method. Effects of preparation conditions on the deposition of fluorid e films have been examined in order to control the thickness and the refrac tive index of the films. It was suggested that the fluoride was formed by t he thermal decomposition of the trifluoroacetate sols generating gaseous ph ases such as (CF3CO)(2)O, CO and CO2. This reaction mechanism seemed to lar gely effect the deposition of the fluoride films in terms of the formation of pores. Characteristics of the fluoride films could be changed by varying the heat treatment. The refractive index of the MgF2 films decreased with increasing heating temperature, which might result from the increased poros ity of the films. Drying the film before the heat treatments was effective in the control of the refractive index.