AG ON THE SI(001) SURFACE - GROWTH OF THE 1ST MONOLAYER AT ROOM-TEMPERATURE

Growth of the first monolayer (ML) of Ag on the Si(001) surface at room temperature has been studied by means of scanning tunneling miroscopy (STM) and low-energy electron diffraction. Ag atoms form single-layer islands with a density of one Ag atom per Si surface atom. These Ag islands exhibit both local 2 X 1 and 2 X 2 order. As the Ag coverage approaches 1 ML, the 2 X 1 order disappears in favor of the 2 X 2 order. One ML of Ag is required to complete the first full surface layer. There is no evidence of three-dimensional Ag growth up to 1 ML. Models of the 2 X 1 and 2 X 2 surface structures are proposed on the basis of the STM images.