Gold-induced faceting on Si(533) surface studied by RHEED

Reflection high energy electron diffraction (RHEED) technique was used to study the Si(5 3 3) surface. On the samples cut 14.42 degrees off the (1 1 1) plane in the [2 (1) over bar (1) over bar] direction, a submonolayer of Au up to 0.628 monolayer (ML) was deposited. Bare Si(5 3 3) surfaces after cleaning in ultrahigh vacuum conditions by short flashing up to about 1500 K did not show a long range older on the macroscopic scale. Upon increasing the coverage of Au, the surface transformed gradually into a flat and perfectly ordered Si(5 3 3) plane at a coverage equal to 0.275 ML, and split into a hill-and-valley structure consisting of (1 1 1) and (1 1 5 5) facets at 0.50 ML of Au, and a combination of (1 1 1) and (3 1 1) facets at 0.628 ML of Au. The crucial role of single atom chains of Au formed on the (1 1 1) terraces is experimentally verified and discussed. It was shown that these chains stabilize the facets and allow the creation of a large macroscopic Si(5 3 3) plane. We suggest that this mechanism can also be operative in the case of Si(1 1 5 5) and Si(3 1 1) planes. (C) 2001 Elsevier Science Ltd. All rights reserved.