Comparison of cobalt and titanium silicides for SALICIDE process and shallow junction formation

A comparison of TiSi₂ and CoSi₂ for the SALICIDE (self-aligned silicide) process is presented. Both TiSi₂ and CoSi₂ are formed by RTA in nitrogen. The comparison is based on the formation kinetics, film properties, process compatibilities, and electrical properties. The results are summarized in table form. Co silicide is found to be a better candidate for use in SALICIDE process for submicron devices because it has a less severe lateral gate-S/D encroachment problem, less sensitivity to oxygen, higher resistivity to dry/wet etch, less film stress, better sheet resistance control, less junction leakage, the capability to form low-resistance polycide, and shallow junctions. However, substrate cleaning must ensure no SiO₂ on Si surfaces that are to be converted to CoSi₂