EPITAXIAL POLY- AND MONOCRYSTALLINE CAF2 FILMS

CaF2 films were deposited onto (100) cleavage faces of NaCl in a high-vacuum bell-jar system. The dependence of structure on substrate temperature and film thickness was studied by transmission electron microscopy and diffraction. When the substrate temperature was around 350°C during deposition, a simple (100)CaF2//(100)NaCl with 〈110〉CaF2//〈100〉NaCl epitaxial monocrystalline orientation was found. Complex (110)CaF2//(100) NaCl with average 〈111〉CaF2// 〈100〉NaCl epitaxial polycrystalline orientations were found when the substrate was in the 150°-250°C range during deposition. Hard-sphere models of the CaF2 and NaCl faces were used to interpret these results qualitatively. © 1970 The American Institute of Physics.