Ellipsometric measurements on single-crystal silicon spheres [for Avogadro's constant determination]

Beside other parameters the growth of oxide layers on silicon surfaces depends on the surface preparation and on the crystal orientation. Measurements of the oxide layer thicknesses on silicon spheres are described. The results show a strong dependence on the crystal orientations which may originate from the polishing process. After HF-etching this orientation effect cannot be distinguished anymore.