Stability of silver thin films on cobalt and nickel silicides

Silver thin films were deposited on cobalt and nickel silicides to evaluate the thermal stability of the films during vacuum annealing. Rutherford backscattering spectrometry of annealed films revealed film changes to occur at 700 °C. Scanning electron microscopy of annealed films shows grain coarsening of the Ag film with increasing anneal temperature. At 650 °C, tears appear in the film. Increasing temperature up to 700 °C agglomerates the film. X-ray diffraction glancing angle scans revealed no phase changes in annealed films. Scans from the as-deposited case and the 700 °C, both show the same reflection peaks being present. Secondary ion mass spectroscopy depth profiling revealed trace amounts of Ag at the silicide/silicon interface following a heat treatment. This occurrence appears to be temperature independent. Equal amounts of Ag were discovered at the silicide interface for all samples annealed from 450 up to 700 °C.