Energetic electron avalanches and mode transitions in planar inductively coupled radio-frequency driven plasmas operated in oxygen

M. Zaka-ul-Islam, K. Niemi, T. Gans, D. O'Connell

Research output: Contribution to journalArticlepeer-review


Space and phase resolved optical emission spectroscopic measurements reveal that in certain parameter regimes, inductively coupled radio-frequency driven plasmas exhibit three distinct operation modes. At low powers, the plasma operates as an alpha-mode capacitively coupled plasma driven through the dynamics of the plasma boundary sheath potential in front of the antenna. At high powers, the plasma operates in inductive mode sustained through induced electric fields due to the time varying currents and associated magnetic fields from the antenna. At intermediate powers, close to the often observed capacitive to inductive (E-H) transition regime, energetic electron avalanches are identified to play a significant role in plasma sustainment, similar to gamma-mode capacitively coupled plasmas. These energetic electrons traverse the whole plasma gap, potentially influencing plasma surface interactions as exploited in technological applications. (C) 2011 American Institute of Physics. [doi:10.1063/1.3612914]

Original languageEnglish
Article number041501
Pages (from-to)1-3
Number of pages3
JournalApplied Physics Letters
Issue number4
Publication statusPublished - 25 Jul 2011


  • TIME

Cite this