THE DEPOSITION OF SILICON ON METAL SINGLE-CRYSTAL SURFACES, STUDIED BY RAIRS, LEED AND AES

We report here low-energy electron diffraction (LEED), Auger electron (AES) and reflection-absorption infrared spectroscopic (RAIRS) studies of the adsorption of disilane (Si2H6) on the hexagonal Ru(0001) surface at room temperature. Initial steps show the formation of an adsorbed SiH fragment which is easily decomposed to leave elemental silicon at 450 K. The room temperature LEED patterns show a coverage dependence, with a transition from a (2 x 2) pattern at low coverage to a mixed (2 x 2) and (1.5 x 1.5) pattern towards saturation. Annealing of the saturated surface to 800 K results in the formation of an ordered overlayer with a (3 X 3) R18 LEED pattern which, in combination with AES data, is assigned to an incommensurate layer of ruthenium silicide.