Biaxially oriented CaF2 films on amorphous substrates

Biaxially oriented CaF2 films have been created by first using an oblique incidence vapor flux to deposit CaF2 onto an amorphous surface to form vertically aligned nanorods which served as seeds to grow a more continuous CaF2 capping layer under a subsequent normal incidence flux deposition. The entire film possesses a unique {1 1 1}〈1 2 1〉 biaxial texture as shown by X-ray pole figure analysis and transmission electron microscopy (TEM). This unique texture formation is a result of shadowing and surface diffusion effects. This biaxially oriented film on an amorphous substrate may be useful as a buffer layer to grow active semiconductor devices.