Formation of twinned two-bilayer-high islands during initial stages of Si growth on Si(111)√3x√3-B

We investigated the initial stages of Si molecular-beam epitaxial growth on a Si(111)root 3 x root 3-B surface using scanning tunneling microscopy. Ln the initial stapes, Si islands one or two bilayers (BL) high are formed. The number of Si atoms contained in these islands depends on the surface B concentration. The larger the surface B concentration, the more Si atoms there are in the 2BL-high islands. Furthermore, comparison between the positions of adatoms in the root 3 x root 3 reconstruction On the Si islands and the substrate shows that the 2BL-high islands are twinned with the substrate, but that the BL-high islands are not twinned. (C) 1998 Elsevier Science B.V. All rights reserved.