Plasma Chemistry and Plasma Processing

, Volume 8, Issue 2, pp 225–246

Transfer of F in the reaction of SF6 with SOF4: Implications for SOF4 production in corona discharges


  • R. J. Van Brunt
    • National Bureau of Standards
  • L. W. Sieck
    • National Bureau of Standards
  • I. Sauers
    • Oak Ridge National Laboratory
  • M. C. Siddagangappa
    • Indian Institute of Science

DOI: 10.1007/BF01016159

Cite this article as:
Van Brunt, R.J., Sieck, L.W., Sauers, I. et al. Plasma Chem Plasma Process (1988) 8: 225. doi:10.1007/BF01016159


The temperature (T) and electric field-to-gas pressure (E/P) dependences of the rate coefficientk for the reaction SF6+SOF4→SOF5+SF5 have been measured. ForT<270 K,k approaches a constant of 2.1×10−9 cm3/s, and for 433>T>270 K,k decreases withT according tok (cm3/s)=0.124 exp [−3.3 lnT(K)]. ForE/P<V/cm·torr,k has a constant value of about 2.5×10−10 cm3/s, and for 130 V/cm·torr>E/P>60 V/cm·torr, the rate is approximately given byk (cm3/s)∼7.0×10−10 exp (−0.022E/P). The measured rate coefficient is used to estimate the influence of this reaction on SOF4 production from negative, point-plane, glow-type corona discharges in gas mixtures containing SF6 and at least trace amounts of O2 and H2O. A chemical kinetics model of the ion-drift region in the discharge gap is used to fit experimental data on SOF4 yields assuming that the SF6+SOF4 reaction is the predominant SOF4 loss mechanism. It is found that the contribution of this reaction to SOF4 destruction falls considerably below the estimated maximum effect assuming that SF6 is the predominant charge carrier which reacts only with SOF4. The results of this analysis suggest that SF6 is efficiently deactivated by other reactions, and the influence of SF6+SOF4 on SOF4 production is not necessarily more significant than that of other slower secondary processes such as gas-phase hydrolysis.

Key Words

Corona dischargeschemical reactionsrate coefficientsexperimental
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© Plenum Publishing Corporation 1988