Filamentary double layers

Theisen, William; Carpenter, R.T.; Merlino, R. L.

doi:10.1063/1.870733

Cited by 8 publications

(5 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similar DP and TP configurations can be obtained by using apertures rather than grids (Torven 1982, Torven et al 1985, Merlino and Loomis 1990. Filamentary DLs have been studied in TP devices using a variable aperture (Theisen et al 1994). The plasma source can be a heated cathode plasma column rather than a hot filament discharge (Plamondon et al 1988, Lindberg 1992, Volwerk 1993.…”

Section: Anode Double Layer Devicesmentioning

confidence: 99%

A review of recent laboratory double layer experiments

Charles

2007

Plasma Sources Sci. Technol.

245

225

View full text Add to dashboard Cite

Recent developments in laboratory double layers from the late 1980s to the spring of 2007 are reviewed. The paper begins by a lead up to electric double layers in the laboratory. Then an overview of the main double layer devices and properties is presented with an emphasis on current-free double layers. Some of the double layer models and simulations are analysed before giving a more complete description of current-free double layers in radiofrequency plasmas expanding in a diverging magnetic field. Astrophysics double layers are briefly reported. Finally, applications of double layers to the field of plasma processing and electric propulsion are discussed.

show abstract

Section: Anode Double Layer Devicesmentioning

confidence: 99%

A review of recent laboratory double layer experiments

Charles

2007

Plasma Sources Sci. Technol.

245

225

View full text Add to dashboard Cite

show abstract

“…It is also of interest to investigate a process which has been proposed to give low-frequency amplitude modulations of the HF waves excited at a double layer, namely Langmuir collapse [19]. Langmuir collapse is a nonlinear process in which waves are trapped within a density cavity.…”

Section: Comparison With Theorymentioning

confidence: 99%

Bursts of high-frequency plasma waves at an electric double layer

Gunell

Brenning

Torvén

1996

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

The high-frequency (HF) oscillations, which are driven by the electron beam on the high-potential side of an electric double layer, are investigated in a laboratory experiment. A new HF probe design has made it possible to achieve a combination of absolute amplitude calibration and spatial resolution which, for such high frequencies, has not been achieved before. The HF waves convert about 20% of the beam energy to oscillations within a region extending from 100 to 400 Debye lengths on the high-potential side of the double layer. This makes the HF waves the dominant mechanism of local tapping of the beam energy, and the modified energy and particle balance is investigated. The HF waves propagate with an approximately constant phase velocity which is slightly smaller than the beam velocity. Time-averaged measurements locate them to a HF region, extending approximately from 5 to 15 cm from the double layer, with a typical half width of 10 cm for the time-averaged electric field amplitude. Time-resolved measurements show, however, a much more narrow structure. The envelope of the electric field amplitude has a single maximum within the HF region and a typical half width of 1 - 2 cm (about one wavelength) along the beam. We call this envelope `the HF spike'. The position of the HF spike changes in an apparently irregular fashion within the HF region and it moves with velocities in the range . The spatial increase and decrease in amplitude of the wave is exponential over nearly two orders of magnitudes, with electron-folding distances of only about 5 mm, so the maximum of the envelope is very sharp. The amplitude increase agrees approximately with the growth rate from linear beam-plasma theory and the maximum amplitude observed agrees with saturation by beam trapping. The strong spatial decrease in the wave amplitude is not understood. It is proposed that the motion of the HF spike is caused by fluctuations, on the ion acoustic time scale, both in the growth length and in the starting point for wave growth at the double layer, which moves back and forth. This motion is shown to be strongly correlated to the motion of the HF spike in a particular case. Amplitude modulations, as observed by a stationary probe, are found on two time scales. On a slower time scale of typically , the motion of the HF spike, together with its limited spatial extent, gives rise to a temporal burst. Within these bursts the waves are also modulated on a much faster time scale of 10 - 30 ns (the wave period is 3 ns). The HF spike cannot be interpreted as a linear superposition of waves with the constant phase velocity measured, because this wave packet would have a spatial extention at least ten times larger than the width of the HF spike.

show abstract

“…In particular, the axial profiles of the plasma potential show that a DL is generated near the inlet of z = 0 at all oxygen gas concentrations. It was found that the outline of the DL was curved for O 2 gas concentrations of 5 and 10% by the proposed scaling of the DL potential drop [39,40]. In plasma processing applications, structured electrodes can be used to enhance the plasma density, the ion and the radical fluxes to the wafer.…”

Section: Discussionmentioning

confidence: 99%

“…where ε 0 , m and e are the vacuum permitivity, the mass and electric charge of electrons, respectively. In equation ( 1), the positive exponent r takes the value 2/3 for the plane DL and decreases as the DL curvature increases [39]. According to equation ( 2) and the current density j estimated from [40], the numerical values of the exponent are r = 0.19 and r = 0.03 for O 2 concentrations of 5% and 10%, respectively.…”

Section: Axial Structures Of Plasma Parameters At Various Oxygen Gas ...mentioning

confidence: 99%

“…On the other hand, in the case of 10% O 2 , the potential drop is ΔV DL = 1.3 V and its thickness is Δz DL = 35 mm corre sponding to the distance from z = 5 to 40 mm. The scaling law of the DL potential with the parameter j (Δz DL ) 2 , where j is the current density across the DL is proposed as the following expresssion [39]:…”

Section: Axial Structures Of Plasma Parameters At Various Oxygen Gas ...mentioning

confidence: 99%

See 1 more Smart Citation

Spatial structure of radio-frequency capacitive discharge plasma with ring-shaped hollow electrode using Ar and O₂ mixture gases

Ohtsu¹,

Takasaki²,

Schulze³

2019

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

Oxygen plasma processing [1] is one method in the important techniques for semiconductor device fabrication. Radio frequency (RF) oxygen plasma is widely used for dry ashing of a photoresist [1, 2] and preparation of an oxide film [3], sterilization of medical products [4,5], etc. On the other hand, inductively coupled plasmas [6,7] and microwave plasmas [8,9] were investigated for these applications using oxygen gas. Recently, one process for producing micro electro mechanical systems devices is also treated by the RF oxygen plasma [10,11]. These processes are mainly attained by the reaction due to oxygen atoms dissociated in the oxygen plasma. For the ashing process, conventional RF capacitive plasmas often suffer from low processing rate. Thus, it is required to realize a higher processing rate to improve the productivity. In order to increase the processing rate, RF hollow-electrode discharge plasmas with various shapes have been proposed [12][13][14][15][16][17].Negative ions, that is, oxygen ions, are also generated in the RF oxygen plasma [18][19][20][21][22][23][24]. The negative ions play important roles in the RF oxygen plasma structure [24]. The presence of the negative ions influences the structure of the plasma

show abstract

Filamentary double layers

Cited by 8 publications

References 14 publications

A review of recent laboratory double layer experiments

A review of recent laboratory double layer experiments

Bursts of high-frequency plasma waves at an electric double layer

Spatial structure of radio-frequency capacitive discharge plasma with ring-shaped hollow electrode using Ar and O₂ mixture gases

Contact Info

Product

Resources

About

Filamentary double layers

Cited by 8 publications

References 14 publications

A review of recent laboratory double layer experiments

A review of recent laboratory double layer experiments

Bursts of high-frequency plasma waves at an electric double layer

Spatial structure of radio-frequency capacitive discharge plasma with ring-shaped hollow electrode using Ar and O2 mixture gases

Contact Info

Product

Resources

About

Spatial structure of radio-frequency capacitive discharge plasma with ring-shaped hollow electrode using Ar and O₂ mixture gases