Characterization of mechanochemically polished (111) surface of silicon crystal by diffuse x-ray scattering

Diffuse x-ray scattering technique was applied to characterize the surface of a (111) silicon wafer polished mechanochemically. Extra diffuse scattering, which is considered to be attributable to localized strain fields, was detected. The localized lattice distortions were of similar characteristics to those found in a (111) surface lapped with white alundum (No. 2000) and etched by 30∼60 μm [S. Yasuami and J. Harada, J. Appl. Phys. 52, 3989 (1981)]. The thickness of the damaged layer induced by mechanochemical polishing was only about 15 μm, however, which is much smaller than that obtained by lapping (about 100 μm). This is the first observation of the damage left in a mechanochemically polished (111) silicon surface.