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 t emperatures (500-900 K) with the scanning tunneling microscope. During the growth of two-dimensional islands, we observe three different gro wth 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 gr owing with high growth speed. A model of hindered nucleation on the fa ulted part of the (7 x 7) reconstruction explains the experimental res ults.