Morphology of mesa surfaces on Si(111) prepared by molecular beam epitaxy at temperatures around the (7 × 7)-“1 × 1” surface phase transition

Development of surface morphology in Si molecular beam epitaxy on mesa-structured Si(111) at temperatures around the (7 × 7)-“1 × 1” surface phase transition was studied by atomic force microscopy. Significant changes in surface morphology were found for a small increase in temperature near the surface phase transition, accompanied by a strong increase in step-free area dimension. This behavior is reported for the first time for epitaxial silicon growth, but supports earlier in situ studies of the thermal decay of 2-dimensional islands and voids on Si(111) close to the surface phase transition using low energy electron microscopy by Hibino et al. (Phys. Rev. B 63, 245402, 2001). The observed changes in surface morphology clearly demonstrate the interplay of crystal growth and the surface phase transformation. In particular, the simultaneous appearance of two surface phases under certain conditions and their specific influence on the growth behavior are discussed with regard to this matter.