Accession Number:

ADA285177

Title:

New Methods for Treatment of Electron Correlation and Surface Dynamics (FY91 AASERT)

Descriptive Note:

Annual rept. 1 Jun 1993-30 May 1994

Corporate Author:

CALIFORNIA UNIV LOS ANGELES DEPT OF CHEMISTRY AND BIOCHEMISTRY

Personal Author(s):

Report Date:

1994-05-30

Pagination or Media Count:

4.0

Abstract:

The SiGe results were discussed in detail in the last AASERT report, so we eschew them here. The F2 reactive scattering on Si100 was the first study in a series to ascertain the kinetics of surface processes, including etching of silicon. We calculated reaction probabilities for F2 impinging on silicon, as a function of translational and vibrational energy in the F2 molecules. We find that translational excitation is slightly more effective than vibrational excitation at increasing the reactivity of F2, but that vibrational excitation is most effective for producing precursors leading to etching SiF2. We find that F-atom abstraction, where one Si-F bond is formed while the other F atom in the F2 molecule leaves the surface, is a very probable reaction due to the enormous exothermicity of the reaction -100 kcalmol exothermic do deposit only one F on the silicon surface and -200 kcalmol to deposit both F atoms. These scattered F atoms do not have time to equilibrate with the surface, as is illustrated by the fact that they are translationally hot and do not come off in a cosine distribution. We have also recently studied the reaction of F2 molecules with stepped and defective Si100 surfaces.

Subject Categories:

  • Inorganic Chemistry
  • Physical Chemistry
  • Atomic and Molecular Physics and Spectroscopy
  • Nuclear Physics and Elementary Particle Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE