Study of plasma‐polyethylene interactions using electron beam‐generated plasmas produced in Ar/SF<sub>6</sub> mixtures

Walton, Scott G.; Lock, Evgeniya H.; Ni, Angxiu; Baraket, Mira; Fernsler, R. F.; Pappas, Daphne; Strawhecker, Kenneth E.; Bujanda, A. A.

doi:10.1002/app.32249

Cited by 29 publications

(19 citation statements)

References 33 publications

(38 reference statements)

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“…Figure shows that the flux scales with density, despite the differences in source geometry and beam operation. Two important points to note are that (1) globally, the flux of ions and electrons leaving a plasma are equal and (2) in this system, the magnetic field causes a net ion flux radially and net electron flux axially . Broadly, the results confirm that a correlation exists between discharge current, plasma density, and ion flux at adjacent surfaces.…”

Section: Resultssupporting

confidence: 52%

“…This implies a direct relationship between the source term, S i , the plasma density, n e , and the flux, Γ i , to the walls. For sheet beams (planar geometry), the flux can be estimated using,

{normalΓ}_{i} ≅ D_{a} \cdot n_{i} / l,

where D a is the ambipolar diffusion coefficient, n i = n e is the ion density at the beam axis, and l is the distance to the wall . Figure shows that the flux scales with density, despite the differences in source geometry and beam operation.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Correlating charge fluence with nanoparticle formation during in situ plasma synthesis of nanocomposite films

Ghosh

Boris

Hernández

et al. 2017

Plasma Processes & Polymers

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Plasmas enable the fabrication of nanocomposites via in situ reduction of metal precursors dispersed in polymer films. The mechanism for reduction has not yet been revealed and it is not known how plasma parameters affect nanoparticle formation. Here, we present a systematic study using a low‐pressure, pulsed electron beam generated argon plasma to treat silver cation‐containing polyacrylic acid films. The background pressure, treatment time, period, and pulse width are varied to influence charged species generation. We show a direct correlation between nanoparticle density, as assessed by ultraviolet‐visible absorbance analysis, and the charge fluence. Although the experiments could not separate the specific role of ions and electrons, our results demonstrate the importance of charged species to nanoparticle formation.

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Section: Resultssupporting

confidence: 52%

{normalΓ}_{i} ≅ D_{a} \cdot n_{i} / l,

Section: Resultsmentioning

confidence: 99%

Correlating charge fluence with nanoparticle formation during in situ plasma synthesis of nanocomposite films

Ghosh

Boris

Hernández

et al. 2017

Plasma Processes & Polymers

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“…33 From inspection, it is clear that species production is proportional to (1) the beam current density, (2) the cross section for its production and, (3) the partial pressure of its parent. From this, there are several important implications that distinguish electron beam produced plasmas from their discharge counterparts, which will be discussed next.…”

Section: Plasma Productionmentioning

confidence: 99%

Electron Beam Generated Plasmas for Ultra Low T_eProcessing

Walton

Boris

Hernández

et al. 2015

ECS J. Solid State Sci. Technol.

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The Naval Research Laboratory (NRL) has developed a processing system based on an electron beam-generated plasma. Unlike conventional discharges produced by electric fields (DC, RF, microwave, etc.), ionization is driven by a high-energy (∼ few keV) electron beam, an approach that can be attractive to atomic layer processing applications. In particular, high electron densities (10 10 -10 11 cm −3 ) can be produced in electron beam generated plasmas, where the electron temperature remains between 0.3 and 1.0 eV. Accordingly, a large flux of ions can be delivered to substrate surfaces with kinetic energies in the range of 1 to 5 eV. This provides the potential for controllably etching and/or engineering both the surface morphology and chemistry with monolayer precision. This work describes the electron beam driven plasma processing system, with particular attention paid to system characteristics and the ability to control the generation and delivery of ions to the surface and their energies. Electron beam generated plasmas are produced by injecting a highenergy electron beam into a gas background, which will ionize, dissociate, and excite atoms or molecules as it traverses the gas volume. While the basic inelastic processes that lead to species production are the same as those in discharge plasmas, the use of energetic electron beams to drive production results in plasmas that have very different properties than conventional discharges. Some of these properties are attractive for plasma-based atomic layer processing applications where, whether etching, depositing, or chemically modifying materials, fine control over the flux and energy of ions is needed. In the case of atomic layer etching, perhaps the single most important need is to tightly control the kinetic energy of ions incident to the processing surface so as to avoid damage while maintaining a reasonable etch rate. [1][2][3] In this regard, a significant advantage of beam-driven plasmas is the inherently low electron temperature T e , which is typically a fraction of an eV in most gas mixtures of technological interest. Importantly, this is true regardless of the plasma density. Thus, one can produce a large fluence of reactive ion and neutral species where the kinetic energy of the ions is as low as a few eV.The interest in electron beam generated plasmas for materials processing can be traced back at least 4 decades. In the early 1970s Bunshah 4 described an electron beam vapor deposition system that utilizes an electron beam to both vaporize the metal and "activate" the background gas. It was also noted by Dugdale 5 that high-energy electron beam systems developed for welding could be employed for "soft vacuum vapor deposition" in a manner similar to that of Bunshah. In the 1980s, Collins and co-workers at Colorado State University, developed electron beam produced plasmas for plasma enhanced chemical vapor deposition of SiO 2 . 6,7 This system used a sheet-like beam of multi-keV electrons injected parallel to the growth substrate. A similar configurat...

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“…Fluorine-containing plasmas are often used for the surface hydrophobization of polymer materials [1,2,3,4,5,6,7,8] and for dry-etching in the semiconducting industry [9,10,11,12]. In the latter, the addition of oxygen is used to enhance the etching rate [11].…”

Section: Introductionmentioning

confidence: 99%

“…Selli et al found that repeated SF 6 treatment caused more stable hydrophobicity [7]. Walton et al found a negligible ageing effect after one year for the sample treated for the longest treatment time of 60 s, but this was not the case for the samples treated for shorter times [6]. Mrad et al observed the ageing of PET, whereas PVC was stable even 210 days after treatment [5].…”

Section: Introductionmentioning

confidence: 99%

Comparison of SF6 and CF4 Plasma Treatment for Surface Hydrophobization of PET Polymer

et al. 2018

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The fluorination of the polymer polyethylene terephthalate in plasma created from SF6 or CF4 gas at various pressures was investigated. The surface was analysed by X-ray photoelectron spectroscopy and water contact angle measurements, whereas the plasma was characterized by optical emission spectroscopy. The extent of the polymer surface fluorination was dependent on the pressure. Up to a threshold pressure, the amount of fluorine on the polymer surface and the surface hydrophobicity were similar, which was explained by the full dissociation of the SF6 and CF4 gases, leading to high concentrations of fluorine radicals in the plasma and thus causing the saturation of the polymer surface with fluorine functional groups. Above the threshold pressure, the amount of fluorine on the polymer surface significantly decreased, whereas the oxygen concentration increased, leading to the formation of the hydrophilic surface. This effect, which was more pronounced for the SF6 plasma, was explained by the electronegativity of both gases.

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Study of plasma‐polyethylene interactions using electron beam‐generated plasmas produced in Ar/SF₆ mixtures

Cited by 29 publications

References 33 publications

Correlating charge fluence with nanoparticle formation during in situ plasma synthesis of nanocomposite films

Correlating charge fluence with nanoparticle formation during in situ plasma synthesis of nanocomposite films

Electron Beam Generated Plasmas for Ultra Low T_eProcessing

Comparison of SF6 and CF4 Plasma Treatment for Surface Hydrophobization of PET Polymer

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Study of plasma‐polyethylene interactions using electron beam‐generated plasmas produced in Ar/SF6 mixtures

Cited by 29 publications

References 33 publications

Correlating charge fluence with nanoparticle formation during in situ plasma synthesis of nanocomposite films

Correlating charge fluence with nanoparticle formation during in situ plasma synthesis of nanocomposite films

Electron Beam Generated Plasmas for Ultra Low TeProcessing

Comparison of SF6 and CF4 Plasma Treatment for Surface Hydrophobization of PET Polymer

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Product

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Study of plasma‐polyethylene interactions using electron beam‐generated plasmas produced in Ar/SF₆ mixtures

Electron Beam Generated Plasmas for Ultra Low T_eProcessing