Strain relaxation of epitaxial SiGe layer and Ge diffusion during Ni silicidation on cap-Si/SiGe/Si(0 0 1)

Strain relaxation of the epitaxial SiGe layer and Ge diffusion during nickel silicidation by rapid thermal annealing the structure of Ni(ffi14 nm)/ cap-Si(ffi26 nm)/Si0.83Ge0.17/Si(0 0 1) at the elevated annealing temperatures, TA, were investigated by X-ray diffraction analyses of highresolution v–2u scan and reciprocal space mapping. The analyses showed a much larger strain relaxation at a lower TA and a reduction in Ge content in the SiGe layer of Ni/SiGe/Si(0 0 1) after thermal annealing compared to the case of cap-Si/SiGe/Si(0 0 1). The results indicate that the strain relaxation of the SiGe layers in NiSi/SiGe/Si(0 0 1) is related to the phenomena of NiSi agglomeration and penetration into the SiGe layer during silicidation at elevated anneal temperatures 750 8C. At elevated TA 750 8C, Ge diffused into the intact cap-Si area during silicidation.