Ellipsometry of surface layers on a 1-kg sphere from natural silicon

Abstract

We have investigated surface layers on a monocrystalline float-zone, n-type (2400–2990Ωcm) sphere with the diameter of 93.6004mm. Ellipsometric spectra in the visible–ultraviolet range reveals the presence of thin layers of amorphous Si as well as oxide overlayer. We have also prepared a series of flat Si samples, polished using slurries with 1–6μm grits; the overlayers were examined by mid–infrared ellipsometry, including the range of polar vibrations of the SiO bonds. AFM measurements on the sphere were used to test the models of its surface.