Ti mediated highly oriented growth of uniform and smooth Ni(Si0.8Ge0.2) layer for advanced contact metallization

Uniform and highly oriented NiSi0.8Ge0.2 layer is achieved by using a Ti interlayer during Ni germanosilicidation. Compared with the reference sample, the morphology of the grown Ni(Si0.8Ge0.2) layer with a Ti interlayer is improved with a better uniformity and smoother surface and interface. The Ni(Si0.8Ge0.2) layer is highly oriented grown on Si0.8Ge0.2 substrate at 500 °C annealing in the case of 5 nm Ti interlayer, with the preferred orientation relationships of (010) Ni(Si0.8Ge0.2) || (001) Si0.8Ge0.2 and (101) Ni(Si0.8Ge0.2) || (110) Si0.8Ge0.2. In addition, most of Ti atoms from the original interlayer diffuses toward the surface after annealing. The reduced Ni diffusion is conducive for the uniform reaction between Ni and Si0.8Ge0.2, resulting in highly oriented Ni(Si0.8Ge0.2) grown on Si0.8Ge0.2.