Numerical simulations of electrical asymmetry effect on electronegative plasmas in capacitively coupled rf discharge

Journal Article · Sat Jan 01 04:00:00 EST 2011 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3530626· OSTI ID:21538008

Quanzhi, Zhang; Wei, Jiang; Younian, Wang ^[1]; Lujing, Hou ^[2]

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1. School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)
2. Max Planck Institute for Extraterrestrial Physics, 85748 Garching (Germany)

Recently a so-called electrical asymmetry effect (EAE), which could achieve high-degree separate control of ion flux and energy in dual-frequency capacitively coupled radio-frequency (CCRF) discharges, was discovered theoretically by Heil et al. [J. Phys. D: Appl. Phys. 41, 165202 (2008)] and was confirmed by experiments and theory/numerical simulations later on for electropositive argon discharges. In this work simulations based on particle-in-cell/Monte Carlo collision are performed to study the EAE on electronegative oxygen plasmas in geometrically symmetric CCRF discharges. Dual frequency discharges operating at 13.56 and 27.12 MHz are simulated for different pressures and the results are compared with those of electropositive argon discharges at the same conditions. It is found that in general the EAE on oxygen discharges has similar behavior as on argon discharge: The self-bias voltage {eta} increases monotonically and almost linearly with the increase in the phase angle {theta} between the two driving voltages in the range 0<{theta}<90 deg. , and the maximum ion energy varies by a factor of 3 by adjusting {theta}. However, the ion flux varies with {theta} by {+-}12% for low pressure and by {+-}15% for higher pressure, due primarily to an enhanced plasma series resonance, which then leads to dramatic changes in plasma density, power absorption and consequently the electronegativity. This may place a limitation for achieving separate control of ion energy and flux for electronegative plasma via the EAE.

• OSTI ID: 21538008
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 1 Vol. 109; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ARGON
ASYMMETRY
CALCULATION METHODS
CHARGED PARTICLES
COLLISIONS
COMPUTERIZED SIMULATION
ELECTRIC DISCHARGES
ELECTROMAGNETIC RADIATION
ELECTRONEGATIVITY
ELEMENTS
FLUIDS
GASES
HIGH-FREQUENCY DISCHARGES
IONS
MONTE CARLO METHOD
NONMETALS
OXYGEN
PLASMA
PLASMA DENSITY
PLASMA PRESSURE
PLASMA SIMULATION
RADIATIONS
RADIOWAVE RADIATION
RARE GASES
RESONANCE
SIMULATION
SYMMETRY