Enhanced formation of low-resistivity TiSi2 contacts for deep submicron devices

Low resistivity C54-TiSi₂ is currently the most commonly used silicide for metal contacts in ultralarge scale integrated circuits devices. In the present paper, we review recent results of investigations on the effects of stress and high temperature sputtering on the formation of C54-TiSi₂. Enhanced formation of C54-TiSi₂ on (001)Si by tensile stress and high temperature sputtering is correlated to the growth of thicker amorphous interlayer at the Ti/(001)Si interface. The enhanced transformation is attributed to the presence of higher density of silicide crystallites, which serve as the nucleation sites for the C49-TiSi₂, in the amorphous layer. As a result, the average grain size of C49-TiSi₂ is smaller which leads to lower C49- to C54-TiSi₂ transformation temperature.