Copper silicide nanocrystals on hydrogen-terminated Si(001)

In this paper we describe the surface characterization of Cu deposited onto nominally-flat and roughened hydrogen-terminated Si(001) surfaces in ultra-high vacuum using scanning tunneling microscopy. Cu forms Cu3Si 3D-islands with markedly different geometries depending on the surface roughness of the underlying H-terminated silicon surface. Anisotropic islands oriented perpendicular to the dimer-rows are observed on the nominally-flat H-terminated surface, while mostly isotropic islands are observed on the rough-engineered H-terminated surface. These results could have implications with respect to both surface-templated growth of nanostructures and Cu-based microelectronics.