The Influence of Impurities on Cobalt Silicide Formation

Abstract

Cobalt silicide formation has been studied using thin films of Co on Si wafers with different impurity contents in the metal and with thin or thick native oxide at the Co/Si interface. The incorporation of impurities into the film was controlled by changes of the pressure during Co deposition. Two RTP systems with two different annealing ambients and heat sources were used for silicidation. For Co films with low contaminant level, thin or thick native oxide can be dissolved and good quality CoSi2 is formed. For Co films with high impurity level in the presence of thick native oxide, the silicidation can be performed, delayed, or even inhibited, depending on film thickness and annealing conditions.