The effect of thin (0.2 to 0.8nm) Ni films upon a H-terminated Si(111) substrate surface was studied by using strain-sensitive X-ray diffraction. It was reported that Ni deposition onto H-terminated Si surface apparently did not cause film growth, but rather diffused into the Si crystal, creating a so-called Ni diffusion layer up to Ni deposits which were 0.8nm thick. Measured rocking curves of the Si 113 reflection and integrated intensities of the rocking curves for the substrate provided information about the evolution of the strain field introduced near to the substrate surface during Ni diffusion into the substrate. Comparing the measured and calculated rocking curves indicated that compression of the {111} spacing of the Si occurred gradually up to an Ni thickness of 0.6nm, and that above this thickness, strain relaxation occurred. It was found that the slope of the integrated intensity of the rocking curve versus X-ray wavelength was related to the strain field near to the surface, in the same way that the shape of the rocking curves was related to the strain field near to the surface. Dynamical diffraction calculations indicated that measurement of the slope of the integrated intensity of the rocking curve versus X-ray wavelength was useful for strain analysis, because the dependence was not only sensitive

to strain fields, but was also insensitive to the effect of absorption by the overlayer, which otherwise would cause deformation of the shape of the rocking curve.

Strain Due to Nickel Diffusion into Hydrogen-Terminated Si(111) Surface. T.Emoto, K.Akimoto, A.Ichimiya, K.Hirose: Applied Surface Science, 2002, 190[1-4], 113-20