An update of argon inelastic cross sections for plasma discharges

Thin films of SiO x C y H have been prepared by plasma enhanced (PE)CVD in a surface-wave, microwave reactor. The films were deposited in direct mode by using hexamethyldisiloxane (HMDSO) as the precursor, and mixtures of oxygen/argon as the plasma gas. Analysis of the plasma by optical emission spectroscopy (OES) showed that, under reaction conditions, the molecules of the precursor are not greatly fragmented in the plasma. This suggests that polymerization occurs after adsorption of the precursor species on the surface of the growing films. The chemical structure and composition of the films were examined by Fourier-transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). A strong correlation is found between the composition and bonding structure of the thin films and the oxygen:HMDSO ratio in the plasma gas. Raising the oxygen concentration leads to an increase in the growth rate and to the removal of the organic groups from the films that, for O 2 :HMDSO ratios greater than 0.8, reach a composition close to silicon dioxide. It has been shown that the Auger parameter of silicon determined by XPS depends on the composition of the films (e.g., 1714.5 for O 2 :HMDSO = 0, and 1712.3 for O 2 :HMDSO = 0.75). It is shown that this parameter can be taken as a measurement of the polarizability of the films. It is concluded that surfatron launchers are a versatile set-up for an efficient control of the composition and properties of thin films of SiO x C y H prepared by PECVD.

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“…[30] This high electron density must be responsible of the high deposition rates obtained with this reactor.…”

Section: ±3mentioning

confidence: 97%

Deposition of Thin Films of SiO_xC_yH in a Surfatron Microwave Plasma Reactor with Hexamethyldisiloxane as Precursor

Walkiewicz-Pietrzykowska

Cotrino

González‐Elipe

2005

Chemical Vapor Deposition

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“…These coefficients are obtained by suitable averaging over the electron energy distribution function (EEDF) computed using the freeware Boltzmann solver BOLSIGþ 40 with a cross-section set of 38 states presented in Ref. 26 and extracted from LXCAT, 41,42 and including electron-electron collisions. For all conditions, the excitation frequency remains smaller than the electron momentum transfer frequency.…”

Section: B Reactions Rate Coefficients and Transport Parametersmentioning

confidence: 99%

Electron confinement and heating in microwave-sustained argon microplasmas

Hoskinson

Gregório

Parsons

et al. 2015

Journal of Applied Physics

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We systematically measure and model the behavior of argon microplasmas sustained by a broad range of microwave frequencies. The plasma behavior exhibits two distinct regimes. Up to a transition frequency of approximately 4 GHz, the electron density, directly measured by Stark broadening, increases rapidly with rising frequency. Above the transition frequency, the density remains approximately constant near 5 × 1020 m–3. The electrode voltage falls with rising frequency across both regimes, reaching approximately 5 V at the highest tested frequency. A fluid model of the plasma indicates that the falling electrode voltage reduces the electron temperature and significantly improves particle confinement, which in turn increases the plasma density. Particles are primarily lost to the electrodes at lower frequencies, but dissociative recombination becomes dominant as particle confinement improves. Recombination events produce excited argon atoms which are efficiently re-ionized, resulting in relatively constant ionization rates despite the falling electron temperature. The fast rates of recombination are the result of high densities of electrons and molecular ions in argon microplasmas.

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“…2, these coefficients were obtained by suitable averaging over a calculated EEDF. [22][23][24][25] In this work, and we stress that this is the only difference between the models, we use a Maxwellian EEDF for simplicity. Our interest is in the general behavior of the microplasma throughout a large frequency spectrum rather than precise quantitative agreement with experiments.…”

Section: à3mentioning

confidence: 99%

Modeling of microplasmas from GHz to THz

Gregório

Hoskinson

Hopwood

2015

Journal of Applied Physics

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We present a study of atmospheric-pressure microdischarges sustained over a wide range of continuous excitation frequencies. A fluid model is used to describe the spatial and temporal evolution of the plasma properties within a 200 μm discharge gap. At 0.5 GHz, the behavior is similar to a typical rf collisional discharge. As frequency increases at constant power density, we observe a decrease in the discharge voltage from greater than 100 V to less than 10 V. A minimum of the voltage amplitude is attained when electron temporal inertia delays the discharge current to be in phase with the applied voltage. Above this frequency, the plasma develops resonant regions where the excitation frequency equals the local plasma frequency. In these volumes, the instantaneous quasi-neutrality is perturbed and intense internal currents emerge ensuring a low voltage operation range. This enhanced plasma heating mechanism vanishes when the excitation frequency is larger than the local plasma frequency everywhere in the plasma volume. For a typical peak electron density of 5×1020 m−3, this condition corresponds to ∼0.2 THz. Beyond the plasma frequency, the discharge performs like a low loss dielectric and an increasingly large voltage is necessary to preserve a constant absorbed power.

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An update of argon inelastic cross sections for plasma discharges

Cited by 140 publications

References 71 publications

Deposition of Thin Films of SiO_xC_yH in a Surfatron Microwave Plasma Reactor with Hexamethyldisiloxane as Precursor

Deposition of Thin Films of SiO_xC_yH in a Surfatron Microwave Plasma Reactor with Hexamethyldisiloxane as Precursor

Electron confinement and heating in microwave-sustained argon microplasmas

Modeling of microplasmas from GHz to THz

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An update of argon inelastic cross sections for plasma discharges

Cited by 140 publications

References 71 publications

Deposition of Thin Films of SiOxCyH in a Surfatron Microwave Plasma Reactor with Hexamethyldisiloxane as Precursor

Deposition of Thin Films of SiOxCyH in a Surfatron Microwave Plasma Reactor with Hexamethyldisiloxane as Precursor

Electron confinement and heating in microwave-sustained argon microplasmas

Modeling of microplasmas from GHz to THz

Contact Info

Product

Resources

About

Deposition of Thin Films of SiO_xC_yH in a Surfatron Microwave Plasma Reactor with Hexamethyldisiloxane as Precursor

Deposition of Thin Films of SiO_xC_yH in a Surfatron Microwave Plasma Reactor with Hexamethyldisiloxane as Precursor