Titanium Silicide on Si:P With Precontact Amorphization Implantation Treatment: Contact Resistivity Approaching $1 \times 10^{-9}$ 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 + TiSi
_x
) and achieve ultralow contact resistivity (ρ
_c
) of (1.3 - 1.5) × 10
^-9
Ω · cm
²
on Si:P. This PCAI + TiSi
_x
technique utilizes light amorphization (low-energy implantation), thin Ti and TiSi
_x
film, and moderate thermal budget (500°C-550°C): these features are compatible with modern CMOS manufacturing. Moreover, the PCAI + TiSi
_x
-induced ρ
_c
reduction is proved universal on both n- and p-Si. With additional characterizations, we find that the silicidation-induced ρ
_c
variation is not merely a Schottky barrier height tuning effect. The electrical and physical characterizations suggest that the low ρ
_c
is strongly correlated with the formation of interfacial TiSi
_x
crystallites between amorphous TiSi alloy and Si.