Distribution Radiale de la Densité des Atomes Métastables dans les Plasmas Produits par un Champ Electrique Continu ou de Haute‐Fréquence

Abstract

The radial density distribution of metastable Ar(SP,) and resonant Ar(lP,) atoms L determined experimentally in two types of electrical discharges of cylindrical shape: the positive column plasma of a Dc discharge and the plasma produced by an electromagnetic surface wave. The exitation and deexcitation rates for Ar(SP,) by electron collisions are determined as a function of radius from the measured radial population density profile using a population density balance equation. These rate coefficients are obtained for various electron density values on the axis. The published values for these coefficients in the positive column plasma assume that they are independent of the discharge current. In this work, it is shown that these coefficients actually decrease 88 the electron density increasetl. I n a more general way, the results obhined indicate that the examination of the radial density distributions of exited atoms is a powerful method for determining the kinetics of their creation and destruction.

Travelling-wave-sustained discharges

“…In fact, regarding this, the spectroscopy diagnostics appeared as very suitable method for studying TWSDs. A lot of data have been accumulated [4,5,115,126,[133][134][135][136][137][138][139][140][141] for gas temperature T g , spatial distribution of spectral line intensities I L (r) and excited-state population densities N k (r) in SWSDs by applying optics spectroscopy techniques. The further extension of these methods has been towards results for plasma parameters (plasma density and electron temperature) which involves, however, kinetic models of the discharges.…”

Plasma spectroscopy for polymer deposition

“…The composition of the gases feed to the discharge was either H2, 02, C2H2, trimethylethoxysilane or hexamethyldisilazane, diluted with argon (90-99 %). 3. Results and discussion.…”

Diagnostics of inductively amplified magnetron discharges by optical emission, absorption spectroscopy, and Langmuir probe measurements

“…The values of ␣ and a are given in Table II for several absorption lines. 4,5 The source linewidth ␦ s , was measured with a Fabry-Perot interferometer 16 and the plasma linewidth ␦ p , was calculated for a Doppler broadening at Tϭ300 K, as it is usual for a low power ͑less than 50 W͒ and a low pressure ͑less than 0.2 Torr͒ argon discharge. It is assumed that the absorption length is the same (L ϭ25 cm) for all the present experimental conditions, since the volume of the plasma expands in all the reactor vessels with the rf coil.…”