X-ray diffraction investigations on Au/Si alloy films

Abstract

Gold/silicon binary mixtures are prepared by depositing thin gold films onto Si(111) single crystals and subsequently annealing at various temperatures. The structure of the films is studied in situ with the help of an ultra-high-vacuum X-ray diffraction chamber. After deposition at room temperature the gold films are homogeneous with a plane-parallel morphology. After annealing at 630 K the Au 111 peak suddenly disappears in the X-ray spectrum indicating that a eutectic melt has been formed. Cooling leads to a regeneration of the peak at 590 K. This temperature is distinctly smaller than the eutectic temperature reported in the literature (643 K). Obviously small gold islands are formed which are embedded into the silicon surface.