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 Si_0.8Ge_0.2/Si(100) was studied. A uniform flattened Ni(Si_0.8Ge_0.2) 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 Si_0.8Ge_0.2 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.