title: Optical emission spectroscopy in reactive hollow cathode arc discharge plasmas - Local distribution of active species during the deposition of hard carbon films.
abstract: A low pressure arc plasma discharge from a hollow LaB(6)-cathode with up to 100 A discharge current is used to create plasmas of high density. Typical values for the electron density and temperature in PETRA ( Plasma Engineering and Technology Research Assembly) are n(e)=10(12)-10(13) cm(-3) and T(e)=5-20 eV. The ionization ratio is typically 1-10%. Optical emission spectroscopy has been applied to investigate the processes within the plasma which lead to the deposition of thin carbon films. In these experiments hydrogenated carbon films (a-C:H) have been deposited on Si-substrates by introducing hydrocarbon gases (CH(4), C(2)H(2)) into He- and Ar-plasmas. Space resolved optical emission spectroscopy using an in-situ translation mechanism of the optical fibre has been performed to measure the local concentrations of CH-radicals, carbon ions and of the excitation of He-neutrals. In addition the hydrogen liberated by the dissociation of the hydrocarbon molecules has been measured. The dissociation of the hydrocarbon molecules takes place as a localized process in the vicinity of the reactive gas inlet.
authors.affiliation: Institut für Werkstoffe der Energietechnik, Forschungszentrum Jülich GmbH, D-52425, Jülich, Germany.
authors.forename: V
authors.initials: V
authors.lastname: Hemel
authors.forename: H
authors.initials: H
authors.lastname: Bolt
authors.forename: F
authors.initials: F
authors.lastname: Koch
authors.forename: H
authors.initials: H
authors.lastname: Nickel