Enhancement of pure volume negative ion production using a grid bias method or a magnetic filter method

Jyobira, Yasuhiro; Ito, Daisuke; Fukumasa, Osamu

doi:10.1063/1.2805368

Cited by 3 publications

(2 citation statements)

References 9 publications

(11 reference statements)

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“…In PEGASES concept, the source of negative ion is, generally, a gridded RF plasma source equipped with a magnetic filter (MF), i.e. an external magnetic field whose lines are perpendicular to the plasma flow direction, which enhances the production of negative ions [10]. Furthermore, the magnetic filter impedes the electron transport and limits drastically the electron current that can reach the MF downstream region [11].…”

Section: Introductionmentioning

confidence: 99%

Expansion of alternatively extracted ion–ion beam in a low pressure collisional medium

Oudini

Bendib

2020

Plasma Sources Sci. Technol.

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The aim of this paper is to investigate, through particle-in-cell with Monte Carlo collisions (PIC-MCC) simulations, the effects of collisions on the expansion of an ion–ion beam formed by the alternate extraction of oppositely charged ions. This beam is extracted from an ion–ion plasma, formed in the downstream of a radiofrequency magnetically filtered iodine electronegative plasma, by the mean of two extraction grids. In this grid system, the screen grid is biased with a square voltage waveform, in the low MHz range, while the acceleration grid is grounded. The collisionless interaction between the extracted ion packets involves and enhances electrostatic waves propagating at beam velocity. Our results show that in addition to these electrostatic waves, the presence of significant fraction of low energy ions, produced by charge exchange, beside extracted fast ions gives rise to two-stream instability. Furthermore, space and time dependent electric field might accelerate the slow ions, produced by charge exchange collision. This acceleration, involving Landau damping and its inverse mechanism, is mainly due to the interaction between ions and potential patterns inherent to two-stream instability.

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Section: Introductionmentioning

confidence: 99%

Expansion of alternatively extracted ion–ion beam in a low pressure collisional medium

Oudini

Bendib

2020

Plasma Sources Sci. Technol.

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“…We also applied this method to negatve-ion production in RF hydrogen plasma, where the negative hydrogen ion production was enhanced by the decrease in e [11]. In the case of RF discharge plasma, the grid bias method was found to be quite suitable for optimizing the plasma conditions for negative ion production, compared with the magnetic filter method [12,13].…”

Section: Introductionmentioning

confidence: 99%

Efficient production of negative hydrogen ions in RF plasma by using a self-biased grid electrode

Kato¹,

Iizuka²

2017

IJERA

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ABSTRACT:Volume production of negative hydrogen ions is established efficiently in a pure hydrogen RF discharge plasma by using a self-biased grid electrode for production of low electron-temperature and high density plasma. Using this electrode both high and low electron temperature plasmas are produced in the regions separated by the grid electrode in the chamber, in which the electron temperature in the downstream region is controlled by the mesh size and plasma production parameters. The production rate of negative ions depends strongly on the electron temperature varied by the RF input power and hydrogen pressure. In the case of the grid electrode with the 5 mesh/in., the negative hydrogen ions are produced effectively in the downstream region in the hydrogen pressure range of 0.9 − 2.7 Pa. In addition, the production rate of the negative ion H − raises from 62 % to 87 % at 0.9 Pa by changing the RF power from 20 W to 80 W.

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Properties and etching rates of negative ions in inductively coupled plasmas and dc discharges produced in Ar/SF6

Draghici

Stamate

2010

Journal of Applied Physics

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Negative ion production is investigated in a chamber with transversal magnetic filter operated in dc or inductively coupled plasma (ICP) modes in Ar/SF6 gas mixtures. Plasma parameters are evaluated by mass spectrometry and Langmuir probe for different discharge conditions. The density ratio of negative ion to electron exceeded 300 in dc mode while it was below 100 in the ICP mode. The possibility to apply a large positive bias to an electrode without affecting the plasma potential and the transition from a negative sheath to anodic glow are also investigated. The etching rates by positive and negative ions are evaluated on silicon substrate for different Ar/SF6 gas ratios. The etching rate by negative ions was with less than 5% smaller than that by positive ions.

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Enhancement of pure volume negative ion production using a grid bias method or a magnetic filter method

Cited by 3 publications

References 9 publications

Expansion of alternatively extracted ion–ion beam in a low pressure collisional medium

Expansion of alternatively extracted ion–ion beam in a low pressure collisional medium

Efficient production of negative hydrogen ions in RF plasma by using a self-biased grid electrode

Properties and etching rates of negative ions in inductively coupled plasmas and dc discharges produced in Ar/SF6

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