Titanium Silicide on Si:P With Precontact Amorphization Implantation Treatment: Contact Resistivity Approaching 1 × 10⁻⁹ Ohm-cm2

In recent CMOS technology, extreme shrinking of contact area at source/drain regions raises serious concerns of high metal/semiconductor contact resistance. Confronting this problem, we introduce a precontact amorphization implantation plus Ti silicidation technique (PCAI + TiSix) and achieve ultralow contact resistivity (ρc) of (1.3 - 1.5) × 10-9Ω · cm2on Si:P. This PCAI + TiSixtechnique utilizes light amorphization (low-energy implantation), thin Ti and TiSixfilm, and moderate thermal budget (500°C-550°C): these features are compatible with modern CMOS manufacturing. Moreover, the PCAI + TiSix-induced ρcreduction is proved universal on both n- and p-Si. With additional characterizations, we find that the silicidation-induced ρcvariation is not merely a Schottky barrier height tuning effect. The electrical and physical characterizations suggest that the low ρcis strongly correlated with the formation of interfacial TiSixcrystallites between amorphous TiSi alloy and Si.