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Author Malyshev, M. V. ♦ Fuller, N. C. ♦ Bogart, K. H. ♦ Donnelly, V. M. ♦ Herman, I. P.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword PHYSICS ♦ CHLORINE ♦ PLASMA DENSITY ♦ PLASMA DIAGNOSTICS ♦ LANGEVIN EQUATION ♦ CHLORINE IONS ♦ FLUORESCENCE ♦ ETCHING ♦ MICROELECTRONICS ♦ ION DENSITY
Abstract Laser induced fluorescence detection of Cl{sub 2}{sup +} has been used to track their relative concentration in a high-density inductively (transformer) coupled (TCP) 10 mTorr chlorine plasma as a function of the 13.56 MHz radio frequency (rf) power. This relative Cl{sub 2}{sup +} number density was compared to the total absolute positive ion density (n{sub i}{sup +}=n{sub Cl}{sup +}+n{sub Cl{sub 2}{sup +}}) obtained with a Langmuir probe. Both n{sub Cl{sub 2}{sup +}} and n{sub i}{sup +} doubled with increasing rf power from 8 to {approximately}55 W in the capacitively coupled (dim) mode. Above the transition from a capacitively to inductively coupled (bright-mode) plasma at {approximately}85{plus_minus}35 W, n{sub Cl{sub 2}{sup +}} decayed with rf power while n{sub i}{sup +} continued to increase. Consequently, Cl{sub 2}{sup +} is the dominant ion in dim-mode operation and Cl{sup +} is the dominant ion in bright-mode operation, at n{sub i}{sup +}{ge}6{times}10{sup 10} cm{sup {minus}3}. With the plasma operating in the reaction ion etch (RIE) mode (the stage powered at 14.56 MHz, and no TCP power) n{sub Cl{sub 2}{sup +}} tracked n{sub i}{sup +} over the entire range of powers (2{endash}150 W). Thus, Cl{sub 2}{sup +} is the dominant ion during capacitively coupled RIE operation. {copyright} {ital 1999 American Institute of Physics.}
ISSN 00036951
Educational Use Research
Learning Resource Type Article
Publisher Date 1999-03-01
Publisher Place United States
Journal Applied Physics Letters
Volume Number 74
Issue Number 12


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