AFM and VAXPS Study of the Influence of Electric Field on Au-Ag Thin Film Structure

Electromigration of Au-Ag thin film on SiO₂ substrate surface under the action of DC electric field was investigated by AFM （atomic force microscope） and VAXPS （variable-angle X-ray photoelectron spectroscopy） technique.AFM images and XPS spectra show that with DC current stressing,surface morphology and structure as well as chemical state of Au-Ag film changed notably,a chemical reaction between Au-Ag film and SiO₂ substrate occurred at interface.A physical model of electromigration mechanism of Au-Ag film on SiO₂ surface was proposed based on the experiment results.These results demonstrate that electromigration of Au and Ag on SiO₂ surface can not be only considered as a simple lateral diffusion,but also involved a complex physical-chemistry process at interface.