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Title: Slope and amplitude asymmetry effects on low frequency capacitively coupled carbon tetrafluoride plasmas

Abstract

We report investigations of capacitively coupled carbon tetrafluoride (CF{sub 4}) plasmas excited with tailored voltage waveforms containing up to five harmonics of a base frequency of 5.5 MHz. The impact of both the slope asymmetry, and the amplitude asymmetry, of these waveforms on the discharge is examined by combining experiments with particle-in-cell simulations. For all conditions studied herein, the discharge is shown to operate in the drift-ambipolar mode, where a comparatively large electric field in the plasma bulk (outside the sheaths) is the main mechanism for electron power absorption leading to ionization. We show that both types of waveform asymmetries strongly influence the ion energy at the electrodes, with the particularity of having the highest ion flux on the electrode where the lowest ion energy is observed. Even at the comparatively high pressure (600 mTorr) and low fundamental frequency of 5.5 MHz used here, tailoring the voltage waveforms is shown to efficiently create an asymmetry of both the ion energy and the ion flux in geometrically symmetric reactors.

Authors:
 [1]; ; ;  [2]; ;  [3]; ; ;  [4]; ; ;  [5]
  1. LPICM-CNRS, Ecole Polytechnique, 91128 Palaiseau (France)
  2. Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Konkoly-Thege Miklós Str. 29-33, H-1121 Budapest (Hungary)
  3. LPP, Ecole Polytechnique-CNRS-Univ Paris-Sud-UPMC, 91128 Palaiseau (France)
  4. Department of Physics, York Plasma Institute, University of York, Heslington, York YO10 5DD (United Kingdom)
  5. Department of Physics, West Virginia University, Morgantown, West Virginia 26506-6315 (United States)
Publication Date:
OSTI Identifier:
22594640
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 119; Journal Issue: 16; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ABSORPTION; AMPLITUDES; ASYMMETRY; CARBON TETRAFLUORIDE; ELECTRIC FIELDS; ELECTRIC POTENTIAL; ELECTRODES; ELECTRONS; HARMONICS; IONIZATION; IONS; MHZ RANGE 01-100; PARTICLES; PLASMA; SIMULATION; SYMMETRY; WAVE FORMS

Citation Formats

Bruneau, B., E-mail: bastien.bruneau@polytechnique.edu, Johnson, E., Korolov, I., Derzsi, A., Donkó, Z., Lafleur, T., Booth, J. -P., Gans, T., O'Connell, D., Greb, A., Brandt, S., Schüngel, E., and Schulze, J. Slope and amplitude asymmetry effects on low frequency capacitively coupled carbon tetrafluoride plasmas. United States: N. p., 2016. Web. doi:10.1063/1.4947453.
Bruneau, B., E-mail: bastien.bruneau@polytechnique.edu, Johnson, E., Korolov, I., Derzsi, A., Donkó, Z., Lafleur, T., Booth, J. -P., Gans, T., O'Connell, D., Greb, A., Brandt, S., Schüngel, E., & Schulze, J. Slope and amplitude asymmetry effects on low frequency capacitively coupled carbon tetrafluoride plasmas. United States. https://doi.org/10.1063/1.4947453
Bruneau, B., E-mail: bastien.bruneau@polytechnique.edu, Johnson, E., Korolov, I., Derzsi, A., Donkó, Z., Lafleur, T., Booth, J. -P., Gans, T., O'Connell, D., Greb, A., Brandt, S., Schüngel, E., and Schulze, J. 2016. "Slope and amplitude asymmetry effects on low frequency capacitively coupled carbon tetrafluoride plasmas". United States. https://doi.org/10.1063/1.4947453.
@article{osti_22594640,
title = {Slope and amplitude asymmetry effects on low frequency capacitively coupled carbon tetrafluoride plasmas},
author = {Bruneau, B., E-mail: bastien.bruneau@polytechnique.edu and Johnson, E. and Korolov, I. and Derzsi, A. and Donkó, Z. and Lafleur, T. and Booth, J. -P. and Gans, T. and O'Connell, D. and Greb, A. and Brandt, S. and Schüngel, E. and Schulze, J.},
abstractNote = {We report investigations of capacitively coupled carbon tetrafluoride (CF{sub 4}) plasmas excited with tailored voltage waveforms containing up to five harmonics of a base frequency of 5.5 MHz. The impact of both the slope asymmetry, and the amplitude asymmetry, of these waveforms on the discharge is examined by combining experiments with particle-in-cell simulations. For all conditions studied herein, the discharge is shown to operate in the drift-ambipolar mode, where a comparatively large electric field in the plasma bulk (outside the sheaths) is the main mechanism for electron power absorption leading to ionization. We show that both types of waveform asymmetries strongly influence the ion energy at the electrodes, with the particularity of having the highest ion flux on the electrode where the lowest ion energy is observed. Even at the comparatively high pressure (600 mTorr) and low fundamental frequency of 5.5 MHz used here, tailoring the voltage waveforms is shown to efficiently create an asymmetry of both the ion energy and the ion flux in geometrically symmetric reactors.},
doi = {10.1063/1.4947453},
url = {https://www.osti.gov/biblio/22594640}, journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 16,
volume = 119,
place = {United States},
year = {Thu Apr 28 00:00:00 EDT 2016},
month = {Thu Apr 28 00:00:00 EDT 2016}
}