Growth processes in Si/Si(111) epitaxy observed by scanning tunneling microscopy during epitaxy

We have studied Si/Si(111) epitaxy during the growth process at high temperatures (500-900 K) with the scanning tunneling microscope. During the growth of two-dimensional islands, we observe three different growth processes: initial sharpening of the corners of triangular Si(111) islands, nucleation in the second layer at domain boundaries of the (7 x 7) reconstruction, and growth at the island edges occurring along rows of the width of the (7 x 7) unit cell. During the coalescence of islands, we observe the development of a new [11(2) over bar] facet growing with high growth speed. A model of hindered nucleation on the faulted part of the (7 x 7) reconstruction explains the experimental results.