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

Journal Article · Thu Apr 28 00:00:00 EDT 2016 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4947453· OSTI ID:22594640

Johnson, E. ^[1]; Korolov, I.; Derzsi, A.; Donkó, Z. ^[2]; Lafleur, T.; Booth, J. -P. ^[3]; Gans, T.; O'Connell, D.; Greb, A. ^[4]; Brandt, S.; Schüngel, E.; Schulze, J. ^[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)

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.

• OSTI ID: 22594640
• Journal Information: Journal of Applied Physics, Vol. 119, Issue 16; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

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