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Title: Atmospheric pressure microplasma jet as a depositing tool

Abstract

An atmospheric pressure microplasma jet is developed for depositing homogeneous thin films from C{sub 2}H{sub 2}. The adjustment of the gas flow through the microplasma jet assures optimal flow conditions as well as minimizes deposition inside the jet. In addition, the formation of an argon boundary layer surrounding the emerging plasma beam separates the ambient atmosphere from the flow of growth precursor. Thereby the incorporation of nitrogen and oxygen from the ambient atmosphere into the deposited film is suppressed. Soft polymerlike hydrogenated amorphous carbon (a-C:H) films are deposited at the rate of a few nm/s on the area of a few square millimeters.

Authors:
; ; ;  [1]
  1. Arbeitsgruppe Reaktive Plasmen, Fakultaet fuer Physik und Astronomie, Ruhr-Universitaet Bochum, Universitaetsstr. 150, 44780 Bochum (Germany)
Publication Date:
OSTI Identifier:
20880182
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 89; Journal Issue: 25; Other Information: DOI: 10.1063/1.2423233; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AMORPHOUS STATE; ARGON; ATMOSPHERES; ATMOSPHERIC PRESSURE; BOUNDARY LAYERS; CARBON; CHEMICAL VAPOR DEPOSITION; GAS FLOW; HYDROGEN; HYDROGENATION; NITROGEN; OXYGEN; PLASMA; PLASMA JETS; PRECURSOR; THIN FILMS

Citation Formats

Benedikt, J., Focke, K., Yanguas-Gil, A., and Keudell, A. von. Atmospheric pressure microplasma jet as a depositing tool. United States: N. p., 2006. Web. doi:10.1063/1.2423233.
Benedikt, J., Focke, K., Yanguas-Gil, A., & Keudell, A. von. Atmospheric pressure microplasma jet as a depositing tool. United States. doi:10.1063/1.2423233.
Benedikt, J., Focke, K., Yanguas-Gil, A., and Keudell, A. von. Mon . "Atmospheric pressure microplasma jet as a depositing tool". United States. doi:10.1063/1.2423233.
@article{osti_20880182,
title = {Atmospheric pressure microplasma jet as a depositing tool},
author = {Benedikt, J. and Focke, K. and Yanguas-Gil, A. and Keudell, A. von},
abstractNote = {An atmospheric pressure microplasma jet is developed for depositing homogeneous thin films from C{sub 2}H{sub 2}. The adjustment of the gas flow through the microplasma jet assures optimal flow conditions as well as minimizes deposition inside the jet. In addition, the formation of an argon boundary layer surrounding the emerging plasma beam separates the ambient atmosphere from the flow of growth precursor. Thereby the incorporation of nitrogen and oxygen from the ambient atmosphere into the deposited film is suppressed. Soft polymerlike hydrogenated amorphous carbon (a-C:H) films are deposited at the rate of a few nm/s on the area of a few square millimeters.},
doi = {10.1063/1.2423233},
journal = {Applied Physics Letters},
number = 25,
volume = 89,
place = {United States},
year = {Mon Dec 18 00:00:00 EST 2006},
month = {Mon Dec 18 00:00:00 EST 2006}
}
  • A nitrogen microplasma jet operated at atmospheric pressure was developed for treating thermally sensitive materials. For example, the plasma sources in treatment of vulnerable biological materials must operate near the room temperature at the atmospheric pressure, without any risk of arcing or electrical shock. The microplasma jet device operated by an electrical power less than 10 W exhibited a long plasma jet of about 6.5 cm with temperature near 300 K, not causing any harm to human skin. Optical emission measured at the wide range of 280-800 nm indicated various reactive species produced by the plasma jet.
  • Atmospheric-pressure microplasma jets (AP{mu}PJs) of Ar and Ar/O{sub 2} gases were generated from the tip of a stainless steel surgical needle having outer and inner diameters of 0.4 and 0.2 mm, respectively, with a rf excitation of 13.56 MHz. The steel needle functions both as a powered electrode and a gas nozzle. The operating power is 1.2-6 W and the corresponding peak-to-peak voltage Vp.p. is about 1.5 kV. The AP{mu}PJ was applied to the localized etching of a polyamide-imide insulator film (thickness of 10 {mu}m) of a copper winding wire of 90 {mu}m diameter. The insulator film around the coppermore » wire was completely removed by the irradiated plasma from a certain direction without fusing the wire. The removal time under the Ar AP{mu}PJ irradiation was only 3 s at a rf power of 4 W. Fluorescence microscopy and scanning electron microscope images reveal that good selectivity of the insulator film to the copper wire was achieved. In the case of Ar/O{sub 2} AP{mu}PJ irradiation with an O{sub 2} concentration of 10% or more, the removed copper surface was converted to copper monoxide CuO.« less
  • A rf microplasma jet working at atmospheric pressure has been characterized for Ar, He, and Ar/CH{sub 4} and Ar/C{sub 2}H{sub 2} mixtures. The microdischarge has a coaxial configuration, with a gap between the inner and outer electrodes of 250 {mu}m. The main flow runs through the gap of the coaxial structure, while the reactive gases are inserted through a capillary as inner electrode. The discharge is excited using a rf of 13.56 MHz, and rms voltages around 200-250 V and rms currents of 0.4-0.6 A are obtained. Electron densities around 8x10{sup 20} m{sup -3} and gas temperatures lower than 400more » K have been measured using optical emission spectroscopy for main flows of 3 slm and inner capillary flows of 160 SCCM. By adjusting the flows, the flow pattern prevents the mixing of the reactive species with the ambient air in the discharge region, so that no traces of air are found even when the microplasma is operated in an open atmosphere. This is shown in Ar/CH{sub 4} and Ar/C{sub 2}H{sub 2} plasmas, where no CO and CN species are present and the optical emission spectroscopy spectra are mainly dominated by CH and C{sub 2} bands. The ratio of these two species follows different trends with the amount of precursor for Ar/CH{sub 4} and Ar/C{sub 2}H{sub 2} mixtures, showing the presence of distinct chemistries in each of them. In Ar/C{sub 2}H{sub 2} plasmas, CH{sub x} species are produced mainly by electron impact dissociation of C{sub 2}H{sub 2} molecules, and the CH{sub x}/C{sub 2}H{sub x} ratio is independent of the precursor amount. In Ar/CH{sub 4} mixtures, C{sub 2}H{sub x} species are formed mainly by recombination of CH{sub x} species through three-body reactions, so that the CH{sub x}/C{sub 2}H{sub x} ratio depends on the amount of CH{sub 4} present in the mixture. All these properties make our microplasma design of great interest for applications such as thin film growth or surface treatment.« less
  • An argon-hydrogen atmospheric pressure microplasma jet was constructed for the treatment of materials. The microplasma jet device operating at 50 W produced long plasma jet of 30 mm with gas temperatures measured, using OH emissions, from 1600 to 2600 K as a function of distance. Excitation temperature was found to be from 7000 to 10 000 K. Through the analysis of H{sub {alpha}} line broadening mechanisms, surprising hot hydrogen atoms H (n=3) were found with temperatures ranging from 12 000 to 19 600 K.
  • Temporal-spatial-resolved optical emission spectroscopy was employed to shed light on the dynamic behavior and the propagation mechanism of a plasma, originating from a dielectric barrier discharge in helium inside a quartz tube for microplasma jet formation. The plasma propagated, regardless of the gas flow direction, in an accelerating manner at a high velocity up to 17 km/s, suggesting that the propagation was sustained by photoionization. A theoretical analysis demonstrated that the enhancement of the local electric field ahead of the ionization front was mainly responsible for the acceleration of the plasma near the electrode.