Secondary Electron Imaging of (7×7) Domains on Si(111) Surfaces

Abstract

A surface imaging technique using secondary electrons, scanning electron surface microscopy has been applied to investigate the transformation of (7×7) domain boundaries on Si(111) and the effect of domain boundaries on Ge solid phase epitaxy. Rearrangement of the domain boundaries takes place to form stabilized structures by annealing for several minutes at 8°C below the (7×7)-(1×1) transition temperature, T_c. The stabilized boundaries are those in the <110> directions which reflect the shape of the (7×7) unit. This is the result of minimizing the energy of the boundaries, which consist of (1×1) structure fluctuating with the size of (7×7) units at T_c-8°C. Ge deposited on the Si (111) surface at room temperature was observed to form islands initially at the domain boundaries and steps during solid phase epitaxy.