Graphoepitaxial recrystallization of Bi films on SiO and C substrates with a surface relief structure

Abstract

The oriented recrystallization of polycrystalline Bi films vapor deposited on amorphous C and SiO substrates with a well defined surface relief grating (“graphoepitaxy”) was studied by TEM and electron diffraction. Recrystallization was achieved by post-deposition annealing above the melting point of Bi and subsequent cooling down to room temperature. The influence of substrate temperature and vapor beam flux during deposition of Bi and of the thickness of the film on the orientation was investigated. It was found that the degree of orientation depends strongly on the surface coverage and accordingly on the mean thickness of the Bi film. Large area, quasi-single crystalline films were obtained for coverages exceeding 90% and having a mean layer thickness of below 42 nm. The results are interpreted by consideration of the energies of cohesion and interfacial tension.