INDIUM-INDUCED RECONSTRUCTIONS OF THE SI(100) SURFACE

The behavior of indium on the Si(100)2 x 1 surface has been studied using scanning tunneling microscopy. At temperatures below 150-degrees-C, low coverages of In form dimer rows that are oriented perpendicular to the underlying Si dimer rows. As the coverage increases, these rows pack into areas of two-dimensional order, forming the 2 x 2 reconstruction at 0.5 ML. For substrate temperatures above 150-degrees-C, low coverages of In form isolated structures which have two maxima in the empty electronic states and a central maximum in the filled states. As the coverage increases, these In structures arrange into rows oriented parallel to the Si dimer rows with an inter-row spacing of four unit cells. At 0.5 ML, the In structures are spaced three unit cells apart along these rows, thus forming the In(4 x 3) reconstruction. Evidence for disruption of the substrate Si dimer bonds and Si displacement due to formation of the 4 x 3 phase is also observed.