Plasma Chemistry and Plasma Processing

, Volume 9, Issue 4, pp 483–496 | Cite as

Aspects of the chemistry of SF6/O2 plasmas

  • K. R. Ryan
Article
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Revised:

Abstract

The production ofSOF4 initiated by the reaction of F atoms withSOF2 has been studied in a gas-flow reactor at 295 K for helium bath gas number densities in the range (3.0–27.0)×1016 cm−3. The effect of O atoms on the formation ofSOF4 has been analyzed in terms of the competing reactionsSOF3+F→SOF4 andSOF3+O→SO2F2+F. This analysis leads to the conclusion that the rate coefficients for these two processes are equal within an uncertainty of about 50%. Furthermore, both experiment and calculations indicate that the rate coefficient for reactions between F atoms andSOF3 is close to its high-pressure limit under the conditions employed. The experiments set a lower limit on this rate coefficient of 5×10−11 cm3 s−1, while calculations based on unimolecular rate theory suggest that it may be greater than 1×10−10 cm3 s−1. These results make it clear that the two reactions shown above cannot explain the relative abundances ofSOF4 andSO2F2 which are observed inSF6/O2 plasmas. This suggests thatSF2 is a major precursor in the sequence of reactions following the dissociation ofSF6.

Key Words

Low-pressure plasma rate coefficients analytical/experimental 
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Copyright information

© Plenum Publishing Corporation 1989

Authors and Affiliations

  • K. R. Ryan
    • 1
  1. 1.CSIRO Division of Applied PhysicsLindfieldAustralia

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