UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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Conference: Bucharest University Faculty of Physics 2005 Meeting


Section: Optics, Spectroscopy, Plasma and Lasers


Title:
Characterization of a tubular plasma reactor with external annular electrodes


Authors:
C. Petcu, I. Ciobanu, S.G. Vlad, E.R. Ionita, B. Mitu, G. Dinescu


Affiliation:
National Institute for Lasers, Plasma and Radiation Physics, Low Temperature Plasma Physics Department, PO Box MG - 36,Magurele - 077125, Bucharest, Romania


E-mail
dinescug@infim.ro


Keywords:
radofrequency plasma, external electrodes, nitrogen plasma emission, plasma polymers, thin film deposition


Abstract:
A plasma configuration with annular external electrodes and its possible application in plasma thin film deposition of polymeric materials is investigated in the present work. The plasma was produced in a cylindrical glass tube of about 8 cm external diameter (7.4 cm internal diameter) and 50 cm length on which two metallic electrodes, parallel one to each other at 2.5 cm distance, are mounted as active RF and grounded electrodes, respectively. The plasma was generated in flowing nitrogen by applying a radiofrequency field (13.56 MHz) between the annular electrodes. The spatial distribution of the nitrogen plasma emission in the capacitively coupled radiofrequency discharge has been studied for various applied power values along the radial and axial directions of the reactor. The optical emission was collected with a typical OES (Optical Emission Spectroscopy) system consisting of optical fiber, monochromator, photomultiplier, amplifier and acquisition system. The fiber end is moveable along the radial and axial direction of the reactor, integrating the axial and respectively radial plasma emission with a space resolution of 3.5 mm. Also, we evaluated the use of this configuration with external electrodes for the deposition of polymeric thin film. The precursor (hexametildisilazan) was introduced in the discharge through a mass flow controller and mixed with the carrier gas (nitrogen) far from the discharge zone in order to insure a uniform transport toward the substrate. The deposition rate and the film composition depend on the substrate position both along the radial and axial direction of the tubular reactor.