Laser Thomson scattering measurements of negative ion density in a glow discharge plasma

Noguchi, Masataka; Ariga, K.; Hirao, T.; Suanpoot, Pradoong; Yamagata, Yuriko; Uchino, Kenji; Muraoka, Katsunori

doi:10.1088/0963-0252/11/1/307

Cited by 24 publications

(33 citation statements)

References 7 publications

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“…The laser flux needs to be sufficiently high so that the photon density in the beam is adequate to detach electrons from all the negative ions in the beam region. The detachment fraction of negative ions is given by the expression [19]:…”

Section: Resultsmentioning

confidence: 99%

“…Another problem is that this method only allows a line averaged density measurement whereas the negative ion density varies spatially within the plasma and local density variations are not considered in the results obtained with this method. Laser Thomson scattering has also been used to measure negative ion density in plasma [19]. The quality of the results obtained were compared with those obtained using Langmuir probes and found to be similar [20].…”

Section: Introductionmentioning

confidence: 99%

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Using the resonance hairpin probe and pulsed photodetachment technique as a diagnostic for negative ions in oxygen plasma

Conway

Sirse

Karkari

et al. 2010

Plasma Sources Sci. Technol.

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In this work the resonance hairpin probe technique has been used for detection of photoelectrons generated during photodetachment experiments performed to determine negative ion density in an inductively coupled oxygen plasma. An investigation of the temporal development of the photoelectron population was recorded with the hairpin probe located inside the laser beam region and at various points outside the beam. Varying the external microwave frequency used to drive the probe resonator allowed the local increase in electron density resulting from photoelectrons to be determined. At a fixed probe frequency, we observed two resonance peaks in the photodetachment signal as the photoelectron density evolved as a function of time. Inside the laser beam the resonance peaks were asymmetric, the first peak rising sharply as compared with the second peak. Outside the laser beam region the peaks were symmetric. As the external frequency was tuned the resonance peaks merge at the maximum electron density. The resonance peak corresponding to maximum density outside the beam occurs at a delay of typically 1-2 s as compared with the centre of the beam allowing an estimate of the negative ion velocity. Using this method, negative ion densities were measured under a range of operating conditions inside and outside the beam.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Using the resonance hairpin probe and pulsed photodetachment technique as a diagnostic for negative ions in oxygen plasma

Conway

Sirse

Karkari

et al. 2010

Plasma Sources Sci. Technol.

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show abstract

“…The reduction of the sheath potential leads to less damage to the film on the substrate by the ions bombardment. For the measurement of negative ion, other methods such as laser photo detachment should be applied in the future 6, 7…”

Section: Resultsmentioning

confidence: 99%

Investigation of Plasma Parameters in a VHF Plasma With Narrow Gap Under High Gaseous Pressure

Muta

Kishida

Tanaka

et al. 2009

Plasma Processes & Polymers

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The plasma parameters in a VHF plasma with a narrow gap under high gaseous pressure were experimentally investigated. As a result of the Langmuir probe measurement for hydrogen plasma with a gap length of 5 mm and a pressure of 1 torr, it was found that the electron temperature (∼10 eV) was high enough to promote the dissociation reaction of SiH4 molecules, and that a large amount of negative ions which could play a role in reducing the sheath potential were produced. On the other hand, the results of the ion measurement using a quadrupole mass spectrometer with an energy analyzer indicated that the highest produced ion was H 3+ and its incident energy to the substrate was low due to the collisions. These results suggest that the condition of high pressure and narrow gap are advantageous for the preparation of high‐quality µc‐Si thin films.

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“…Based on the interpretation of the measured LTS spectra, a novel technique of measuring negative ion densities in plasmas has been proposed [14].…”

Section: Ar/o 2 Plasmamentioning

confidence: 99%

Applicabilities of Laser Thomson Scattering to Various Kinds of Discharge Plasmas.

Suanpoot

Narishige

Yamagata

et al. 2002

J. Plasma Fusion Res.

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In order to establish the applicability conditions of incoherent laser Thomson scattering (LTS) for plasma diagnostics of electron properties to various kinds of discharge plasmas, a method of approach was discussed, and criteria for applicability were established. These criteria were then applied to three representative discharge plasmas: inductively coupled plasmas (ICP) in Ar/CF 4 and Ar/O 2 gases, and a microwave-produced plasma in a H 2 /CH 4 gas. Implications of the results are discussed.

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Laser Thomson scattering measurements of negative ion density in a glow discharge plasma

Cited by 24 publications

References 7 publications

Using the resonance hairpin probe and pulsed photodetachment technique as a diagnostic for negative ions in oxygen plasma

Using the resonance hairpin probe and pulsed photodetachment technique as a diagnostic for negative ions in oxygen plasma

Investigation of Plasma Parameters in a VHF Plasma With Narrow Gap Under High Gaseous Pressure

Applicabilities of Laser Thomson Scattering to Various Kinds of Discharge Plasmas.

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