The annealing of Au particles deposited onto the ultrathin layers of SiO2 on Si (111) has been studied in real time with a high temperature scanning tunnelling microscopy. Annealing did not create significant changes to the morphology of the surface until the surface was heated up to more than 920 K when the gold particles started to display a preference for the step edge. Further heating caused the decomposition of the oxide layer with the formation of voids on the surface in the surface step edge area. Comparison between the gold assisted oxide decomposition and pure oxide decomposition indicates that the two decomposition routes proceed with different mechanisms.
