Effect of P Concentration on Ti Silicide Formation in In-Situ P Doped Epitaxial Si Films

Herein, the effect of P concentration in highly P-doped epitaxial Si films on the formation of Ti silicide therein are investigated. Ti films sputter-deposited on P-doped Si substrates are annealed at different temperatures, and the thus obtained samples are characterized by X-ray diffraction (XRD) and transmission electron microscopy. The former technique revealed that the formation of C54 is suppressed by high P concentrations, while the resistivity of Ti silicide are shown to be independent of P concentration when the C54 phase is fully formed under the condition of sufficient thermal budget. Most importantly, this work confirms the occurrence of a silicidation delay in in situ P-doped epitaxial Si films and demonstrates that this delay increases the temperature of the C49 to C54 phase transition of Ti silicide.