Initial stages of Fe growth on clean and Sb-terminated Si(100) surfaces

The initial stages of Fe growth on clean and Sb-terminated Si(1 0 0) surfac es were investigated with a scanning tunneling microscopy/spectroscopy. Due to the saturation of Si dangling bonds by Sb adatoms, nucleation sites for Fe growth are highly reduced on Sb-terminated Si(1 0 0) surfaces. We find that the sizes of islands grown on Sb-terminated surfaces are larger but th e island densities are smaller than those grown on clean surfaces. Through the local I-V measurements on Fe islands, it was found that the conduction properties gradually changed from semiconducting to metallic as Fe coverage increased. It was explained in terms of the coalescence of Fe clusters and the formation of bulk metallic Fe films. (C) 2001 Elsevier Science B.V. Al l rights reserved.