Reaction of nanometer-sized Cu particles with a SiO2 substrate

The thermal stability of nanometer-sized Cu particles on a 400–500 nm thick SiO2 layer on top of a Si(100) substrate was studied after annealing in ultrahigh vacuum up to 620¿°C. Atomic force microscopy, low-energy ion scattering, Rutherford backscattering spectrometry, and Auger electron spectroscopy measurements clearly show that Cu-silicide islands are formed. A direct reaction of Cu with the SiO2 support is assumed, which is facilitated by a fairly strong metal-support interaction and by the wetting behavior of the silicide islands. Exposure to air at room temperature results in regeneration of the annealed Cu/SiO2 system.