STM STUDY OF EPITAXIAL-GROWTH OF GE ON SI(001)

Germanium thin films epitaxially grown on Si(001) surfaces were investigated with a scanning tunneling microscope (STM). The Ge layers grow epitaxially on the Si substrate at 300-degrees-C forming small islands with vicinal slopes. A narrow terrace at the top of an island exhibits the Ge(001) surface with the (2 x 1) reconstructed structure and the vicinal slopes are found to be the facets of the {015} planes formed by the single-layer steps of the stacked Ge(001) layers. The width of each terrace is 7.1 angstrom and the number of dimers of the dimer rows of the (2 x 1) structure is two. The short dimer rows on the narrow terraces show the highly ordered zigzag pattern. Sizes of the Ge islands were also analyzed examining the mismatch of the Si and Ge lattice constants.