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Title: Capacitively coupled hydrogen plasmas sustained by tailored voltage waveforms: excitation dynamics and ion flux asymmetry

Parallel plate capacitively coupled plasmas in hydrogen at relatively high pressure (~1 Torr) are excited with tailored voltage waveforms containing up to five frequencies. Predictions of a hybrid model combining a particle-in-cell simulation with Monte Carlo collisions and a fluid model are compared to phase resolved optical emission spectroscopy measurements, yielding information on the dynamics of the excitation rate in these discharges. When the discharge is excited with amplitude asymmetric waveforms, the discharge becomes electrically asymmetric, with different ion energies at each of the two electrodes. Unexpectedly, large differences in the $$\text{H}_{2}^{+}$$ fluxes to each of the two electrodes are caused by the different $$\text{H}_{3}^{+}$$ energies. When the discharge is excited with slope asymmetric waveforms, only weak electrical asymmetry of the discharge is observed. In this case, electron power absorption due to fast sheath expansion at one electrode is balanced by electron power absorption at the opposite electrode due to a strong electric field reversal.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [5] ;  [5] ;  [1] ;  [6]
  1. Ecole Polytechnique, Palaiseau (France). LPICM-CNRS
  2. Univ. of Houston, Houston, TX (United States). Plasma Processing Lab., Dept. of Chemical & Biomolecular Engineering; Dutch Inst. for Fundamental Energy Research (DIFFER). FOM Inst.
  3. Univ. of Houston, Houston, TX (United States). Plasma Processing Lab., Dept. of Chemical & Biomolecular Engineering
  4. Univ. degli Studi di Bari (Italy). Dipt. di Chimica
  5. Univ. of York (United Kingdom). York Plasma Inst., Dept. of Physics
  6. Ecole Polytechnique, Palaiseau (France); Univ. Paris-Sud, Palaiseau (France)
Publication Date:
Grant/Contract Number:
SC0001939
Type:
Accepted Manuscript
Journal Name:
Plasma Sources Science and Technology
Additional Journal Information:
Journal Volume: 25; Journal Issue: 4; Journal ID: ISSN 0963-0252
Publisher:
IOP Publishing
Research Org:
Univ. of Michigan, Ann Arbor, MI (United States)
Sponsoring Org:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; tailored voltage waveforms, electrical asymmetry effect, capacitively coupled plasmas, hydrogen discharge, discharge asymmetry, PIC simulations, PROES
OSTI Identifier:
1434929

Bruneau, B., Diomede, P., Economou, D. J., Longo, S., Gans, T., O'Connell, D., Greb, A., Johnson, E., and Booth, J-P. Capacitively coupled hydrogen plasmas sustained by tailored voltage waveforms: excitation dynamics and ion flux asymmetry. United States: N. p., Web. doi:10.1088/0963-0252/25/4/045019.
Bruneau, B., Diomede, P., Economou, D. J., Longo, S., Gans, T., O'Connell, D., Greb, A., Johnson, E., & Booth, J-P. Capacitively coupled hydrogen plasmas sustained by tailored voltage waveforms: excitation dynamics and ion flux asymmetry. United States. doi:10.1088/0963-0252/25/4/045019.
Bruneau, B., Diomede, P., Economou, D. J., Longo, S., Gans, T., O'Connell, D., Greb, A., Johnson, E., and Booth, J-P. 2016. "Capacitively coupled hydrogen plasmas sustained by tailored voltage waveforms: excitation dynamics and ion flux asymmetry". United States. doi:10.1088/0963-0252/25/4/045019. https://www.osti.gov/servlets/purl/1434929.
@article{osti_1434929,
title = {Capacitively coupled hydrogen plasmas sustained by tailored voltage waveforms: excitation dynamics and ion flux asymmetry},
author = {Bruneau, B. and Diomede, P. and Economou, D. J. and Longo, S. and Gans, T. and O'Connell, D. and Greb, A. and Johnson, E. and Booth, J-P},
abstractNote = {Parallel plate capacitively coupled plasmas in hydrogen at relatively high pressure (~1 Torr) are excited with tailored voltage waveforms containing up to five frequencies. Predictions of a hybrid model combining a particle-in-cell simulation with Monte Carlo collisions and a fluid model are compared to phase resolved optical emission spectroscopy measurements, yielding information on the dynamics of the excitation rate in these discharges. When the discharge is excited with amplitude asymmetric waveforms, the discharge becomes electrically asymmetric, with different ion energies at each of the two electrodes. Unexpectedly, large differences in the $\text{H}_{2}^{+}$ fluxes to each of the two electrodes are caused by the different $\text{H}_{3}^{+}$ energies. When the discharge is excited with slope asymmetric waveforms, only weak electrical asymmetry of the discharge is observed. In this case, electron power absorption due to fast sheath expansion at one electrode is balanced by electron power absorption at the opposite electrode due to a strong electric field reversal.},
doi = {10.1088/0963-0252/25/4/045019},
journal = {Plasma Sources Science and Technology},
number = 4,
volume = 25,
place = {United States},
year = {2016},
month = {6}
}