Nucleation in Si(001) Homoepitaxial Growth

Abstract

From low energy electron microscopy observations of the surface topography of Si(001) during homoepitaxial growth at 650 \ifmmode^\circ\else\textdegree\fi{}C, we have determined the nucleation density profile on top of a ``base'' island, and the distribution of the base island radius at the time of nucleation. Comparison with homogeneous nucleation theory yields a typical critical nucleus size of $\ensuremath{\sim}650$ dimers, and allows nucleation on Si(001) to be understood in a common framework with equilibrium step-edge fluctuations and 2D island ripening.