Morphological transformations of thin heteroepitaxial films

Abstract

The features of two-and three-dimensional growth of thin heteroepitaxial films are analysed with allowance for the energy of misfit dislocation (MD) networks. Criteria for distinguishing between Frank-van der Merwe, Stranski-Krastanov and Volmer-Weber growth modes are suggested. For the Stanski-Krastanov mode the transition from layer to island growth is considered to be associated with an increase in the interface energy owing to MD formation. The critical thickness of the pseudomorphic film in the case of the formation of dislocated islands is much less than that in the case of the introduction of MDs into the continuous film and depends on an average migration length of the adatoms. Some theoretical results are compared with experimental results for germanium films obtained by molecular beam epitaxy on Si(001) and Si(111) substrates.