High-temperature interaction of Al with Si(1 0 0) surface at low Al coverages

Using low-energy electron diffraction, Auger electron spectroscopy and STM, the peculiarities of the Al/Si(1 0 0) interface formation at 400–550 °C has been studied. At low Al coverages (∼0.05–0.2 ML), interaction of Al atoms with a top Si(1 0 0) substrate layer proceeds by two competitive mechanisms. First mechanism prevails at Si(1 0 0) surface with a low density of missing-dimer defects and resides in the formation of the specific Al–Si clusters. The second mechanism is stimulated by the presence of missing-dimer defects and resides in substitutional incorporation of Al atoms in the top Si(1 0 0) substrate layer. Both mechanisms result in the liberation of the surface Si atoms which agglomerate into flat islands. The Si mass transport and Al incorporation have been treated quantitatively, the composition of the Al–Si clusters has been estimated and the cluster structural model has been constructed.