Direct REM observation of structural processes on clean silicon surfaces during sublimation, phase transition and epitaxy

Abstract

Reflection electron microscopy (REM) has been applied to an situ study of silicon sublimation, phase transition and epitaxy. Reversible rearrangement of the stepped Si(111) surface from a regular monatomic-step system to step bunching was observed. During long-time annealing by DC at step bunching temperature the formation of step antibands has been found on the stepped Si(111) surface. The antibands are almost parallel to step bands and contain monatomic steps with opposite sign compared to the initial steps. Rearrangements of the Si(111) surface morphology (regular steps ⇔ step bands system ⇔ step band-antiband system) are reversible. During study of initial stages of homoepitaxial growth on Si(111) the areas free from growth islands near the monatomic step have been observed. These areas are characterized by the (7 × 7) structure on the upper terrace, whereas the structure of these areas on the lower terrace is (1 × 1). The reversible monatomic steps clustering during the superstructural transitions at heteroepitaxy of Ge and Au on surface (111) due to displacement of segments of steps restricting the superstructural domains has been found.