AVS 46th International Symposium
    Electronic Materials and Processing Division Thursday Sessions
       Session EM1-ThA

Paper EM1-ThA10
The Passivation of Si(100)-2x1 with Alcohols

Thursday, October 28, 1999, 5:00 pm, Room 608

Session: Chemical Mechanical Planarization
Presenter: T. Bitzer, St. Andrews University, United Kingdom
Authors: T. Bitzer, St. Andrews University, United Kingdom
A. Lopez, St. Andrews University, United Kingdom
N.V. Richardson, St. Andrews University, United Kingdom
Correspondent: Click to Email
Wet chemical etching is a fundamental process in the production of nano-structures on silicon wafers. It has been found that the addition of alcohols such as iso-propanol to an aqueous KOH etchant moderates the etching process, which improves the surface finish.@footnote 1@ In this study, we simulated the conditions at the silicon wafer/etchant interface inside ultra high vacuum (UHV) by the passivation of the Si(100)-2x1 with alcohols ((CH@sub 3@)@sub n@CH@sub 3-n@OH, n=1,2,3), such as ethanol, iso-propanol and tert-butyl alcohol, and post-exposure to H@sub 2@O. Vibrational spectra, taken with high resolution electron energy loss spectroscopy (HREELS), show that alcohol species chemisorb via a deprotonation of the OH group. The alkoxy species are bonded to the silicon dimer through a Si-O-C linkage. We found that post-exposure to H@sub 2@O does not result in a removal of alkoxy species but rather in an oxidation of the Si-Si bond of the silicon dimer. After prolonged H@sub 2@O exposure, 2x1 diffraction spots are absent in LEED. The findings will be compared with the reactivity of alcohols on hydroxylated Si(100)-2x1.@footnote 2@ @FootnoteText@ @footnote 1@ S. A. Campbell, K. Cooper, L. Dixon, R. Earwaker, S. N. Port and D. J. Schiffrin, J. of Micromech. and Microeng. 5, 209 (1995) @footnote 2@ T. Bitzer, N. V. Richardson and D. J. Schiffrin, Surf. Sci. Lett. 382, L686 (1997).