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Title: Effect of radio-frequency power levels on electron density in a confined two-frequency capacitively-coupled plasma processing tool

Abstract

The plasma electron density n{sub e} in a symmetric confined capacitive-coupled plasma processing tool containing Ar/O{sub 2}/C{sub 4}F{sub 8} gas mixtures is studied as a function of two, combined radio frequency (2 MHz+27 MHz) powers. For measuring n{sub e} we have used a floating hairpin resonance probe. The results show a linear increase in n{sub e} with 27 MHz power. Also the density is higher with an increase in 2 MHz power, in contrast with published particle-in-cell simulation results in argon where the plasma density decreased with increases in low frequency voltage, for fixed high frequency current [P. C. Boyle et al., J. Phys. D 37, 697 (2004)]. Analyzing the relative phase between radio frequency current and voltage, we observe slightly lower 2 MHz phase shifts at higher 2 MHz voltage, which is attributed to an increase in the real component of the current through the sheath. This is possible due to the increase in secondary electron emissions arising from ion bombardment, which is favored by an increase in 2 MHz voltage. We therefore conclude that the secondary electrons could play an important role in the discharge process.

Authors:
;  [1]
  1. Plasma Research Laboratory, National Center for Plasma Science and Technology and School of Physical Sciences, Dublin City University, Dublin 9 (Ireland)
Publication Date:
OSTI Identifier:
20778775
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 88; Journal Issue: 10; Other Information: DOI: 10.1063/1.2182073; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ARGON; CARBON FLUORIDES; ELECTRIC POTENTIAL; ELECTRON DENSITY; ELECTRON EMISSION; ELECTRONS; HIGH-FREQUENCY DISCHARGES; ION BEAMS; MHZ RANGE 01-100; MIXTURES; ORGANIC COMPOUNDS; OXYGEN; PHASE SHIFT; PLASMA; PLASMA DENSITY; PLASMA SHEATH; RADIOWAVE RADIATION; RESONANCE; SIMULATION

Citation Formats

Karkari, S.K., and Ellingboe, A.R. Effect of radio-frequency power levels on electron density in a confined two-frequency capacitively-coupled plasma processing tool. United States: N. p., 2006. Web. doi:10.1063/1.2182073.
Karkari, S.K., & Ellingboe, A.R. Effect of radio-frequency power levels on electron density in a confined two-frequency capacitively-coupled plasma processing tool. United States. doi:10.1063/1.2182073.
Karkari, S.K., and Ellingboe, A.R. Mon . "Effect of radio-frequency power levels on electron density in a confined two-frequency capacitively-coupled plasma processing tool". United States. doi:10.1063/1.2182073.
@article{osti_20778775,
title = {Effect of radio-frequency power levels on electron density in a confined two-frequency capacitively-coupled plasma processing tool},
author = {Karkari, S.K. and Ellingboe, A.R.},
abstractNote = {The plasma electron density n{sub e} in a symmetric confined capacitive-coupled plasma processing tool containing Ar/O{sub 2}/C{sub 4}F{sub 8} gas mixtures is studied as a function of two, combined radio frequency (2 MHz+27 MHz) powers. For measuring n{sub e} we have used a floating hairpin resonance probe. The results show a linear increase in n{sub e} with 27 MHz power. Also the density is higher with an increase in 2 MHz power, in contrast with published particle-in-cell simulation results in argon where the plasma density decreased with increases in low frequency voltage, for fixed high frequency current [P. C. Boyle et al., J. Phys. D 37, 697 (2004)]. Analyzing the relative phase between radio frequency current and voltage, we observe slightly lower 2 MHz phase shifts at higher 2 MHz voltage, which is attributed to an increase in the real component of the current through the sheath. This is possible due to the increase in secondary electron emissions arising from ion bombardment, which is favored by an increase in 2 MHz voltage. We therefore conclude that the secondary electrons could play an important role in the discharge process.},
doi = {10.1063/1.2182073},
journal = {Applied Physics Letters},
number = 10,
volume = 88,
place = {United States},
year = {Mon Mar 06 00:00:00 EST 2006},
month = {Mon Mar 06 00:00:00 EST 2006}
}