SURFACE-EXTENDED X-RAY-ABSORPTION FINE-STRUCTURE STUDY OF SILICON DEPOSITED ONTO GAAS(110)

The system Si/GaAs(110) was studied by surface extended x-ray absorpti on fine structure at the silicon K edge, starting from a 0.5 monolayer (ML) coverage up to 3 ML. At very low coverages, the first adsorption site of the silicon has been determined to be above the center of the triangle formed by two arsenic and one gallium surface atoms. The gro wth mode of silicon on this surface obeys a modified version of the St ranski-Krastanov model: the formation of three-dimensional clusters ap pears at 2.5 ML and involves all the deposited silicon atoms. (C) 1996 American Vacuum Society.