Ion beam analysis of silver thin films on cobalt silicides

Using a bilayer technique, cobalt disilicide films were grown on (100) silicon. Silver thin films were subsequently deposited on the silicide layers for evaluation of their thermal stability during vacuum annealing. Rutherford backscattering spectrometry of the annealed films reveals film coarsening at 400 °C after which no changes are intelligible until 700 °C. Scanning electron microscopy of annealed films also shows grain coarsening of the Ag film with increasing anneal temperature. At 650 °C, voids begin to appear in the film. Complete film agglomeration occurs at 700 °C. X-ray diffraction glancing angle scans show no phase changes in the annealed films. Scans from the as-deposited case and the 700 °C, both contain the same reflection peaks. Secondary ion mass spectroscopy depth profiling reveals trace amounts of Ag at the silicide/silicon interface following any amount of heat treatment. Equal amounts of Ag were discovered at the silicide interfaces for all samples annealed from 450 to 700 °C.