Arsenic redistribution during cobalt silicide formation

The redistribution of arsenic during cobalt silicide formation was studied. For the case of cobalt monosilicide (CoSi) formation, arsenic was implanted initially either into the Co or into the Si substrate and for the case of cobalt disilicide (CoSi2) formation, arsenic was implanted initially into either CoSi or into Si substrate. The distribution profiles of arsenic were monitored before and after heat treatment using Rutherford backscattering spectrometry analysis. The redistribution profiles of arsenic were found to be determined by the kinetics of cobalt silicide formation and by annealing at high temperature. It was found that during the silicide formation the motion of arsenic dopants is in the opposite direction to the dominant diffusing species. The details of the dominant diffusing species in cobalt silicide formation and their relationship to the arsenic dopant redistributions are discussed.