The effect of realistic heavy particle induced secondary electron emission coefficients on the electron power absorption dynamics in single- and dual-frequency capacitively coupled plasmas

M. Daksha, A. Derzsi, S. Wilczek, J. Trieschmann, T. Mussenbrock, P. Awakowicz, Z. Donkó, J. Schulze

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

In particle-in-cell/Monte Carlo collisions (PIC/MCC) simulations of capacitively coupled plasmas (CCPs), the plasma-surface interaction is generally described by a simple model in which a constant secondary electron emission coefficient (SEEC) is assumed for ions bombarding the electrodes. In most PIC/MCC studies of CCPs, this coefficient is set to γ = 0.1, independent of the energy of the incident particle, the electrode material, and the surface conditions. Here, the effects of implementing energy-dependent secondary electron yields for ions, fast neutrals, and taking surface conditions into account in PIC/MCC simulations is investigated. Simulations are performed using self-consistently calculated effective SEECs, γ∗, for 'clean' (e.g., heavily sputtered) and 'dirty' (e.g., oxidized) metal surfaces in single- and dual-frequency discharges in argon and the results are compared to those obtained by assuming a constant secondary electron yield of γ = 0.1 for ions. In single-frequency (13.56 MHz) discharges operated under conditions of low heavy particle energies at the electrodes, the pressure and voltage at which the transition between the α- and γ-mode electron power absorption occurs are found to strongly depend on the surface conditions. For 'dirty' surfaces, the discharge operates in α-mode for all conditions investigated due to a low effective SEEC. In classical dual-frequency (1.937 MHz + 27.12 MHz) discharges γ∗ significantly increases with increasing low-frequency voltage amplitude, VLF, for dirty surfaces. This is due to the effect of VLF on the heavy particle energies at the electrodes, which negatively influences the quality of the separate control of ion properties at the electrodes. The new results on the separate control of ion properties in such discharges indicate significant differences compared to previous results obtained with different constant values of γ.

Original languageEnglish
Article number085006
JournalPlasma Sources Science and Technology
Volume26
Issue number8
DOIs
Publication statusPublished - Jul 27 2017

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secondary emission
electron emission
coefficients
electrodes
ions
electrons
particle energy
collisions
cells
simulation
electric potential
electrode materials
surface reactions
metal surfaces
argon
low frequencies
energy

Keywords

  • capacitively coupled plasmas
  • plasma-surface interaction
  • secondary electron emission

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

The effect of realistic heavy particle induced secondary electron emission coefficients on the electron power absorption dynamics in single- and dual-frequency capacitively coupled plasmas. / Daksha, M.; Derzsi, A.; Wilczek, S.; Trieschmann, J.; Mussenbrock, T.; Awakowicz, P.; Donkó, Z.; Schulze, J.

In: Plasma Sources Science and Technology, Vol. 26, No. 8, 085006, 27.07.2017.

Research output: Contribution to journalArticle

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AU - Trieschmann, J.

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AU - Awakowicz, P.

AU - Donkó, Z.

AU - Schulze, J.

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