ULTRA-HIGH-VACUUM REFLECTION ELECTRON-MICROSCOPY STUDY OF STEP-DISLOCATION INTERACTION ON SI(111) SURFACE

Interaction between monatomic steps and dislocation emerging at the surface has been studied by in situ ultra high vacuum reflection electron microscopy (UHV REM). It was shown that during sublimation the motion of the step was suppressed in the dislocation strain field around dislocation core regions. The energy of the step-dislocation interaction was estimated from a mechanical analogy a with pinning phenomenon of an infinitely long string moving in uniform medium. The relaxation time was measured from relaxation processes of the step shape after passing across the dislocation core at the high temperature of sublimation. Dynamical step stiffness was evaluated from measurements of the relaxation time. The data obtained are discussed in the framework of recently developed theories.