Performance of a permanent-magnet helicon source at 27 and 13 MHz

Journal Article · Sat Sep 15 04:00:00 EDT 2012 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4754580· OSTI ID:22086184

Chen, Francis F ^[1]

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1. Electrical Engineering Department, University of California, Los Angeles, California 90095 (United States)

A small helicon source is used to create dense plasma and inject it into a large chamber. A permanent magnet is used for the dc magnetic field (B-field), making the system very simple and compact. Though theory predicts that better antenna coupling will occur at 27.12 MHz, it was found that 13.56 MHz surprisingly gives even higher density due to practical effects not included in theory. Complete density n and electron temperature T{sub e} profiles are measured at three distances below the source. The plasma inside the source is also measured with a special probe, even under the antenna. The density there is lower than expected because the plasma created is immediately ejected, filling the experimental chamber. The advantage of helicons over inductively coupled plasmas (with no B-field) increases with RF power. At high B-fields, edge ionization by the Trivelpiece-Gould mode can be seen. These results are useful for design of multiple-tube, large-area helicon sources for plasma etching and deposition because problems are encountered which cannot be foreseen by theory alone.

• OSTI ID: 22086184
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 9 Vol. 19; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANTENNAS
DEPOSITION
ELECTRON TEMPERATURE
ETCHING
HELICON WAVES
IONIZATION
MAGNETIC FIELDS
MHZ RANGE
PERMANENT MAGNETS
PLASMA DENSITY
PLASMA PRODUCTION
PROBES
SPUTTERING