INVESTIGATION OF THIN FLUORIDE FILMS FOR OPTICAL APPLICATIONS BY SURFACE ANALYTICAL METHODS AND ELECTRON-MICROSCOPY

Impurity contents of loosely packed CaF2 and LaF3 films are analysed b y SNMS depth-profiling. On the basis of TEM investigations a quantitat ive description of the structure of the films is given. The irreversib ly incorporated oxygen contents of the films are nearly independent of the film structures. In contrast, the irreversibly incorporated carbo n contents are proportional to the inner surfaces of the loosely packe d films and to the C-contaminations of appropriate surfaces of compact fluoride samples. It is concluded that the irreversibly incorporated C covers the grain surfaces and the irreversibly incorporated 0 is loc ated preferably within the grains.