| Autor: |
Noriharu Takada, Noriharu Takada, Daiyu Hayashi, Daiyu Hayashi, Koichi Sasaki, Koichi Sasaki, Kiyoshi Kadota, Kiyoshi Kadota |
| Zdroj: |
Japanese Journal of Applied Physics; December 1997, Vol. 36 Issue: 12 pL1702-L1702, 1p |
| Abstrakt: |
This paper reports the absolute density and reaction kinetics of fluorine negative ions (F-) in a low-pressure, high-density CF4plasma excited by helicon-wave discharge. Probe-assisted laser photodetachment has been adopted for the measurement of the F-density. To avoid the deposition of insulated fluorocarbon films on the probe surface, the probe tip was heated to approximately 1000 K. For a CF4gas pressure of 2 mTorr, the ratio of the F-density to the electron density was n-/ne?0.06 in the active discharge plasma with a plasma density of 1.8 ×1012cm-3. In the afterglow, the electron density decreased rapidly with a decay time constant of ?10 µs, while the F-density had a peak at ?15 µs after the termination of the rf power. The ratio n-/neincreased up to ?5.7 in the afterglow. The production and loss processes of F-are discussed based on the experimental observations. |
| Databáze: |
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