CHARACTERIZATION OF THE SI/GAAS(110) INTERFACE BY SOFT-X-RAY SURFACE X-RAY-ABSORPTION FINE-STRUCTURE

Surface x-ray absorption fine structure experiments have been carried out on the system Si/GaAs(110) at coverages ranging from 0.8 to around 2 monolayers (ML) and at room temperature. Polarized experiments have allowed us to propose a model for the silicon adsorption site that has the initial silicon atoms sitting just above the middle of the As-As and Ga-Ga bond along the [001] direction. Above one monolayer, silicon atoms begin to be ordered with a siliconlike structure. At thicker coverages (above 3 ML) the silicon layer is amorphous, which permits a determination of the thickness probed by x-ray absorption using the total electron yield technique.