Slow Positron Annihilation in Silicide Films Formed by Solid State Interaction of Co/Ti/Si and Co/Si

Slow positron beam was used to investigate the solid state reaction of Co/Si and Co/Ti/Si. Variable-energy (0-20 keV) positrons were implanted into samples at different depths. The Doppler broadening of the annihilation γ-ray energy spectra measured at a number of different incident positron energies is characterized by a line-shape parameter, S. It was found that the measured S parameters are sensitive to thin film reaction and crystalline characteristics. In particular, the S parameter of epitavial CoSi₂ formed by the ternary reaction is quite different from that of the polycrystalline CoSi₂ formed by direct reaction of Co with Si.