Effect of Ti interlayer on the formation of epitaxial NiSiGe on strained Si0.8Ge0.2

The effect of an ultrathin titanium (Ti) interlayer on the formation of nickel germanosilicide on strained Si0.8Ge0.2/Si(100) was studied. A uniform flattened Ni(Si0.8Ge0.2) layer is finally formed after rapid thermal annealing. The transition temperature from the Ni-rich germanosilicide phase to the monogermanosilicide phase increases for the incorporation of Ti. The Ti interlayer acting as an inter-diffusion barrier layer well balance the silicidation velocity, which contributes to the achievement of the highly-oriented nickel germanosilicidation. The strain of Si0.8Ge0.2 remains nearly the same after the RTA procedure. Considering the smooth interface between the NiSiGe layer and the SiGe substrate, the approach presented indicates a potential application for S/D contacts in the future CMOS devices.