INITIAL GROWTH MODE OF ER SILICIDE ON SI(111) BY SOLID-PHASE EPITAXY

Er in the 0-2 monolayer (ML) range is deposited on Si(111) at room tem perature and subsequently annealed at 500 degrees C. The silicide laye rs obtained in this way are studied by scanning tunneling microscopy a nd angle-resolved photoemission. Large scale images demonstrate a laye r-by-layer growth mode up to 2 ML at 500 degrees C. This is confirmed by monitoring the dangling bond surface state intensity at (K) over ba r of single layer two-dimensional p(1 x 1) silicide in photoemission v ersus Er coverage. While only monolayer islands are formed up to simil ar to 0.9 ML, double layer bulk-like silicide with (root 3 x root 3)R3 0 degrees superstructure becomes visible above this coverage. For both single and double layer silicide surfaces atomic resolution could be achieved that indicates a remarkable degree of surface atomic order an d very similar surface reconstructions in spite of the different p(1 x 1) and root 3 periodicities.