Epitaxial Growth of Titanium Films on Mica

The oriented overgrowth of titanium films obtained by evaporation in an ultrahigh-vacuum system onto mica was studied in situ by reflection electron diffraction and, after withdrawal from the system, by transmission electron microscopy and diffraction. Films with a thickness of 100 Å or more, prepared on a mica at temperatures of 500°–600°C, are epitaxial single crystals of hexagonal structure; their basal plane is parallel to that of the substrate and the crystallographic axes within the contact planes form an average angle of 30°. These single-crystal films have a smooth surface and are composed of subgrains rotated around the c axis with respect to each other, forming angles up to 4°. Films thinner than 100 Å are only partially oriented. Coalescence in these films takes place at a very early stage of growth and continuous films of about 100 Å are obtained, in contrast with the growth of other metals on mica.