Electron heating modes and frequency coupling effects in dual-frequency capacitive CF4 plasmas

Aranka Derzsi, Edmund Schüngel, Z. Donkó, Julian Schulze

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Two types of capacitive dual-frequency discharges, used in plasma processing applications to achieve the separate control of the ion flux, γi, and the mean ion energy, <Ei>, at the electrodes, operated in CF4, are investigated by particle-in-cell simulations: (i) In classical dual-frequency discharges, driven by significantly different frequencies (1.937 MHz + 2 7.12 MHz), <Ei> and γi are controlled by the voltage amplitudes of the low-frequency and high-frequeny components, φLF and φHF, respectively. (ii) In electrically asymmetric (EA) discharges, operated at a fundamental frequency and its second harmonic (13.56 MHz + 27.12 MHz), φLF and φHF control γi, whereas the phase shift between the driving frequencies, θ, is varied to adjust <Ei>. We focus on the efect of changing the control parameter for <Ei> on the electron heating and ionization dynamics and on γi. We find that in both types of dual-frequency strongly electronegative discharges, changing the control parameter results in a complex effect on the electron heating and ionization dynamics: in classical dual-frequency discharges, besides the frequency coupling affecting the sheath expansion heating, additional frequency coupling mechanisms influence the electron heating in the plasma bulk and at the collapsing sheath edge; in EA dual-frequency discharges the electron heating in the bulk results in asymmetric ionization dynamics for values of θ around 45°, i.e., in the case of a symmetric applied voltage waveform, that affects the dc self-bias generation.

Original languageEnglish
Pages (from-to)346-361
Number of pages16
JournalOpen Chemistry
Volume13
Issue number1
DOIs
Publication statusPublished - 2015

Fingerprint

Plasmas
Heating
Electrons
Ionization
Plasma sheaths
Ions
Plasma applications
Electric potential
Phase shift
Fluxes
Electrodes

Keywords

  • Dual-frequency RF discharges
  • Electrical asymmetry effect
  • Electron heating modes
  • Electronegative plasmas
  • Frequency-coupling effects

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Chemistry

Cite this

Electron heating modes and frequency coupling effects in dual-frequency capacitive CF4 plasmas. / Derzsi, Aranka; Schüngel, Edmund; Donkó, Z.; Schulze, Julian.

In: Open Chemistry, Vol. 13, No. 1, 2015, p. 346-361.

Research output: Contribution to journalArticle

Derzsi, Aranka ; Schüngel, Edmund ; Donkó, Z. ; Schulze, Julian. / Electron heating modes and frequency coupling effects in dual-frequency capacitive CF4 plasmas. In: Open Chemistry. 2015 ; Vol. 13, No. 1. pp. 346-361.
@article{6862a5cf5cc449548ce52d680c91b69d,
title = "Electron heating modes and frequency coupling effects in dual-frequency capacitive CF4 plasmas",
abstract = "Two types of capacitive dual-frequency discharges, used in plasma processing applications to achieve the separate control of the ion flux, γi, and the mean ion energy, <Ei>, at the electrodes, operated in CF4, are investigated by particle-in-cell simulations: (i) In classical dual-frequency discharges, driven by significantly different frequencies (1.937 MHz + 2 7.12 MHz), <Ei> and γi are controlled by the voltage amplitudes of the low-frequency and high-frequeny components, φLF and φHF, respectively. (ii) In electrically asymmetric (EA) discharges, operated at a fundamental frequency and its second harmonic (13.56 MHz + 27.12 MHz), φLF and φHF control γi, whereas the phase shift between the driving frequencies, θ, is varied to adjust <Ei>. We focus on the efect of changing the control parameter for <Ei> on the electron heating and ionization dynamics and on γi. We find that in both types of dual-frequency strongly electronegative discharges, changing the control parameter results in a complex effect on the electron heating and ionization dynamics: in classical dual-frequency discharges, besides the frequency coupling affecting the sheath expansion heating, additional frequency coupling mechanisms influence the electron heating in the plasma bulk and at the collapsing sheath edge; in EA dual-frequency discharges the electron heating in the bulk results in asymmetric ionization dynamics for values of θ around 45°, i.e., in the case of a symmetric applied voltage waveform, that affects the dc self-bias generation.",
keywords = "Dual-frequency RF discharges, Electrical asymmetry effect, Electron heating modes, Electronegative plasmas, Frequency-coupling effects",
author = "Aranka Derzsi and Edmund Sch{\"u}ngel and Z. Donk{\'o} and Julian Schulze",
year = "2015",
doi = "10.1515/chem-2015-0044",
language = "English",
volume = "13",
pages = "346--361",
journal = "Open Chemistry",
issn = "2391-5420",
publisher = "Walter de Gruyter GmbH",
number = "1",

}

TY - JOUR

T1 - Electron heating modes and frequency coupling effects in dual-frequency capacitive CF4 plasmas

AU - Derzsi, Aranka

AU - Schüngel, Edmund

AU - Donkó, Z.

AU - Schulze, Julian

PY - 2015

Y1 - 2015

N2 - Two types of capacitive dual-frequency discharges, used in plasma processing applications to achieve the separate control of the ion flux, γi, and the mean ion energy, <Ei>, at the electrodes, operated in CF4, are investigated by particle-in-cell simulations: (i) In classical dual-frequency discharges, driven by significantly different frequencies (1.937 MHz + 2 7.12 MHz), <Ei> and γi are controlled by the voltage amplitudes of the low-frequency and high-frequeny components, φLF and φHF, respectively. (ii) In electrically asymmetric (EA) discharges, operated at a fundamental frequency and its second harmonic (13.56 MHz + 27.12 MHz), φLF and φHF control γi, whereas the phase shift between the driving frequencies, θ, is varied to adjust <Ei>. We focus on the efect of changing the control parameter for <Ei> on the electron heating and ionization dynamics and on γi. We find that in both types of dual-frequency strongly electronegative discharges, changing the control parameter results in a complex effect on the electron heating and ionization dynamics: in classical dual-frequency discharges, besides the frequency coupling affecting the sheath expansion heating, additional frequency coupling mechanisms influence the electron heating in the plasma bulk and at the collapsing sheath edge; in EA dual-frequency discharges the electron heating in the bulk results in asymmetric ionization dynamics for values of θ around 45°, i.e., in the case of a symmetric applied voltage waveform, that affects the dc self-bias generation.

AB - Two types of capacitive dual-frequency discharges, used in plasma processing applications to achieve the separate control of the ion flux, γi, and the mean ion energy, <Ei>, at the electrodes, operated in CF4, are investigated by particle-in-cell simulations: (i) In classical dual-frequency discharges, driven by significantly different frequencies (1.937 MHz + 2 7.12 MHz), <Ei> and γi are controlled by the voltage amplitudes of the low-frequency and high-frequeny components, φLF and φHF, respectively. (ii) In electrically asymmetric (EA) discharges, operated at a fundamental frequency and its second harmonic (13.56 MHz + 27.12 MHz), φLF and φHF control γi, whereas the phase shift between the driving frequencies, θ, is varied to adjust <Ei>. We focus on the efect of changing the control parameter for <Ei> on the electron heating and ionization dynamics and on γi. We find that in both types of dual-frequency strongly electronegative discharges, changing the control parameter results in a complex effect on the electron heating and ionization dynamics: in classical dual-frequency discharges, besides the frequency coupling affecting the sheath expansion heating, additional frequency coupling mechanisms influence the electron heating in the plasma bulk and at the collapsing sheath edge; in EA dual-frequency discharges the electron heating in the bulk results in asymmetric ionization dynamics for values of θ around 45°, i.e., in the case of a symmetric applied voltage waveform, that affects the dc self-bias generation.

KW - Dual-frequency RF discharges

KW - Electrical asymmetry effect

KW - Electron heating modes

KW - Electronegative plasmas

KW - Frequency-coupling effects

UR - http://www.scopus.com/inward/record.url?scp=84982672443&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84982672443&partnerID=8YFLogxK

U2 - 10.1515/chem-2015-0044

DO - 10.1515/chem-2015-0044

M3 - Article

AN - SCOPUS:84982672443

VL - 13

SP - 346

EP - 361

JO - Open Chemistry

JF - Open Chemistry

SN - 2391-5420

IS - 1

ER -