Plasma Chemistry and Plasma Processing

, Volume 3, Issue 3, pp 329–336 | Cite as

Kinetic studies of SF6 plasmas during etching of Si

  • Werner W. Brandt
  • John J. Wagner


Mass spectrometric kinetic measurements were performed on a dc plasma during the etching of Si by SF6. Neutral plasma particles were permitted to effuse through an aperture in the cathode, via a differentially pumped section, into the ion source of the spectrometer, the sample being mounted on the cathode. The applied voltage was changed in steps, and the resulting mass signal transients for SF x + (x=0−5), F+, S2F 2 + , SiF+, and SiF 3 + were recorded. The SF 5 + , SF 4 + , and SF 3 + signals turned out to be essentially a measure of the unfragmented SF6 present in the plasma, while SF 2 + and SF+ responded in a complex way to the changes of applied voltage. The rate of SiF4 formation was not proportional to the concentration of F atoms or ions present. The S2F2 present in the plasma was probably formed from SF2 and SF radicals, mostly. Slow changes were observed in the signals representing SF 2 + , SF+, S+, F+, and S2F 2 + , presumably related to, or controlled by, gradual changes of the surface undergoing etching. The production and consumption rates of various species were seen to be nearly in balance, and strongly dependent on the applied voltage.

Key words

SF6 Si dc plasma etching kinetics transients mechanism 


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Copyright information

© Plenum Publishing Corporation 1983

Authors and Affiliations

  • Werner W. Brandt
    • 1
  • John J. Wagner
    • 1
  1. 1.Department of Chemistry and Laboratory for Surface StudiesUniversity of Wisconsin-MilwaukeeMilwaukee

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