Optical properties of buried cobalt disilicide layers in silicon

Publisher Website
Google Scholar
Abstract
The optical reflectivity from highly conducting buried and exposed CoSi2 layers produced by Co ion implantation of Si substrates has been measured over the energy range 0.012–6.2 eV (0.2–100 μm). Both as-implanted and high temperature annealed heteroepitaxial layers were investigated. The frequency dependant optical constants associated with the CoSi2 films were derived from the multicomponent reflectivity spectra; the analysis accounted for the contributions from the Si-CoSi2 interfaces. A Drude term was used to describe the free carriers, and a classical oscillator model was included to simulate interband electronic transitions for the CoSi2. The plasma frequency and relaxation time of the free carriers were measured as a function of anneal conditions. A direct correlation between the effective carrier concentration and the measured channeling data from Rutherford backscattering was observed.