Regensburg 2002 – scientific programme
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DS: Dünne Schichten
DS 15: Ionenimplantation: Erzeugung, Nachweis und Ausheilung von Defekten
DS 15.4: Talk
Wednesday, March 13, 2002, 16:00–16:15, HS 32
Composition and structure of mechanically polished Si surfaces by resonant RBS — •E. Wendler1, S. Downes2, C. Jeynes3, J.F. Watts4, J.L. Keddie5, and K.E. Puttick5 — 1Friedrich-Schiller-Universität Jena, Institut für Festkörperphysik, Jena, Germany — 2National Physical Laboratory, Teddington, U.K. — 3University of Surrey, Ion Beam Centre, Guildford, U.K. — 4University of Surrey, School of Mechanical & Materials Engineering, Guildford, U.K. — 5University of Surrey, Department of Physics, Guildford, U.K.
Si wafers of different orientations ((100), (110), (111),
(211) and (311)) were mechanically polished at the National
Physical Laboratory using a procedure comparable with that
applied when fabricating Si spheres for the Avogadro project.
For each orientation the amount of O atoms at the surface
is measured by elastic backscattering spectrometry of
3.03 MeV He ions. Resulting oxide layer thicknesses
are compared to those obtained by spectroscopic ellipsometry and
photoelectron spectroscopy. Furthermore, information is
extracted about the damage in the Si adjacent to the oxide
from the RBS spectra taken in channelling configuration with
1.5 MeV He ions.
Our results show that RBS is capable to give useful information
with respect to surface oxide and surface damage, even if the
layers are only few nanometers thick. The mechanical polishing
introduces additional defects, the concentration of which is
highest for the higher-index axes. The resulting oxide layer
thicknesse are larger than those obtain by the optical
measurements, suggesting that the bulk optical constants may
not be valid for such thin layers.