Theoretical insight into Ar-O-2 surface-wave microwave discharges

• Tipo: Artigo em Revista Científica Internacional
• Data: 2010

Autores

Kutasi, K (Autor) Outra; Guerra, V (Autor) Outra; P. A . Sá (Autor) FEUP

Revista

Título: Journal of Physics D: Applied Physics

Vol. 43 Nº 15

ISSN: 0022-3727

Editora: Institute of Physics Publishing

Indexação

ISI Web of Knowledge - 49 Citações

Scopus - 57 Citações

Outras Informações

ID Authenticus: P-003-6SH

DOI: 10.1088/0022-3727/43/17/175201

Abstract (EN): A zero-dimensional kinetic model has been developed to investigate the coupled electron and heavy-particle kinetics in Ar-O-2 surface-wave microwave discharges generated in long cylindrical tubes, such as those launched with a surfatron or a surfaguide. The model has been validated by comparing the calculated electron temperature and species densities with experimental data available in the literature for different discharge conditions. Systematic studies have been carried out for a surface-wave discharge generated with 2.45 GHz field frequency in a 1 cm diameter quartz tube in Ar-O-2 mixture at 0.5-3 Torr pressures, which are typical conditions found in different applications. The calculations have been performed for the critical electron density for surface-wave propagation, n(e) = 3.74 x 10(11) cm(-3). It has been found that the sustaining electric field decreases with Ar percentage in the mixture, while the electron kinetic temperature exhibits a minimum at about 80% Ar. The charged and neutral species densities have been calculated for different mixture compositions, from pure O-2 to pure Ar, and their creation and destruction processes have been identified. The O-2 dissociation degree increases with Ar addition into O-2 and dissociation degrees as high as 60% can be achieved. Furthermore, it has been demonstrated that the dissociation degree increases with the discharge tube radius, but decreases with the atomic surface recombination of O-atoms. The density of O- negative ions is very high in the plasma, the electronegativity of the discharge can be higher than 1, depending on the discharge conditions.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 14