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 ul trahigh vacuum up to 620 degrees C. Atomic force microscopy, low-energy ion scattering, Rutherford backscattering spectrometry, and Auger electron spe ctroscopy measurements clearly show that Cu-silicide islands are formed. A direct reaction of Cu with the SiO2 support is assumed, which is facilitate d by a fairly strong metal-support interaction and by the wetting behavior of the silicide islands. Exposure to air at room temperature results in reg eneration of the annealed Cu/SiO2 system. (C) 1999 American Institute of Ph ysics. [S0003-6951(99)03120-4].