Bismuth film coalescence determined by ellipsometry

Abstract

The growth and coalescence of thin (1.5–100.0 nm) filmsof bismuth were examined with ellipsometry and atomic force microscopy. The Bi films were thermally evaporated onto oxidized, heated (343 K) Si substrates. An effective medium approximation was used with the ellipsometry data to determine that the films grew in an island growth mode out to a thickness of about 8.0 nm before coalescing into a continuous film. These results were confirmed usingatomic force microscopy which also indicated that the average grain size increased in an almost linear manner with film thickness up to thicknesses around 50.0 nm before levelling off. Surface steps of 0.4 and 0.8 nm suggested that the grains were mainly oriented with the (111) rhombohedral planes parallel to the surface.