The initial stages of Yb silicide phase formation on Si(0 0 1) by solid-phase epitaxy have been studied in a wide range of Yb coverage (up to 20 monolayers (ML)). Morphologically, the grown film reveals both three-dimensional (3D) islands and one-dimensional nanowires of Yb silicide. The nanowires are found only at the earliest stage of silicide film formation, whereas the 3D islands grow in the whole coverage range studied. The coalescence of 3D islands occurs at similar to 20 ML, suggesting high roughness of Yb silicide film. The morphology and structure of the 3D islands are examined. The latter is assumed to be different from hexagonal structure of silicide nanowires. The atomic arrangement of 2D Yb layer between silicide clusters is investigated and the 1 x 5, 1 x 9, and 1 x 3 periodicities are revealed for that phase. (C) 2003 Elsevier B.V. All rights reserved.