Self-diffusion on Si(111) surfaces

Abstract

Using in situ ultrahigh vacuum reflection electron microscopy we have investigated the transition between step-flow and nucleation regimes of homoepitaxy on a Si(111) surface. The minimal interstep distance for two-dimensional nucleation was measured at temperatures 500--850 \ifmmode^\circ\else\textdegree\fi{}C and at the rates of atom deposition 0.01--0.7 ML /s. Dependence of the activation energy on atoms flux, evaluated from the Arrhenius plots of the critical distance, are more complicated than predicted for the simple Einstein relation. Obtained results are discussed in the frames of modest atomistic theories of nucleation. \textcopyright{} 1996 The American Physical Society.