Diagnostics of an inductively coupled plasma in oxygen

Masahiro Tadokoro, Akihiko Itoh, Nobuhiko Nakano, Zoran Lj, Toshiaki Makabe

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)


-Spatial time-integrated and space-time resolved proflies of excited atoms of oxygen were measured by optical emission spectroscopy for inductively coupled plasma (ICP) in oxygen. Discharge was sustained by a single turn coil supplied by 13.56 MHz RF generator delivering 100 and 200 W of power. The spatial emission profiles give the anatomy of the discharge required in order to understand the basic kinetics of ICP. Two types of nonuniformities are observed, azimuthal anisotropy and radial nonuniformity, both caused by spatially dependent energy supply to the electrons. Our experimental results show that oxygen is much more affected by azimuthal anisotropy and radial nonuniformity than argon. It is due to a different role of metastable atoms in kinetics of excitation, whereby stepwise excitation in oxygen is less probable than in argon. Optical emission data are supplemented by Langmuir probe measurements of electron densities and plasma potentials. Electrons gain energy from the time varying fields close to the coil, and the energy is not redistributed along the radius before it is dissipated in excitation, thus the observations are not consistent with the nonlocal theory predictions for the range of pressures, geometry, and power covered in this paper.

Original languageEnglish
Pages (from-to)1724-1732
Number of pages9
JournalIEEE Transactions on Plasma Science
Issue number6
Publication statusPublished - 1998


  • CT image
  • Inductively coupled plasma
  • Plasma ashing
  • Plasma diagnostics
  • Radon inversion

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Condensed Matter Physics


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