title: Evidence of local power deposition and electron heating by a standing electromagnetic wave in electron-cyclotron-resonance plasma.
abstract: Microwave plasmas excited at electron-cyclotron resonance were studied in the 0.5-15 mTorr pressure range. In contrast with low-limit pressure conditions where the plasma emission highlights a fairly homogeneous spatial structure, a periodic spatial modulation (period ∼6.2 cm) appeared as pressure increased. This feature is ascribed to a local power deposition (related to the electron density) due to the presence of a standing electromagnetic wave created by the feed electromagnetic field (2.45 GHz) in the cavity formed by the reactor walls. Analysis of the electron energy probability function by Langmuir probe and optical emission spectroscopy further revealed the presence of a high-energy tail that showed strong periodic spatial modulation at higher pressure. The spatial evolution of the electron density and of the characteristic temperature of these high-energy electrons coincides with the nodes (maximum) and antinodes (minimum) of the standing wave. These spatially-modulated power deposition and electron heating mechanisms are then discussed.
authors.affiliation: Département de Physique, Université de Montréal, Montréal, Québec, Canada H3C 3J7.
authors.forename: A
authors.initials: A
authors.lastname: Durocher-Jean
authors.affiliation: Département de Physique, Université de Montréal, Montréal, Québec, Canada H3C 3J7.
authors.forename: L
authors.initials: L
authors.lastname: Stafford
authors.affiliation: Université de Toulouse; UPS, INPT; LAPLACE, 118 route de Narbonne, 31062 Toulouse Cedex 9, France and CNRS; LAPLACE; 31062 Toulouse, France.
authors.forename: S
authors.initials: S
authors.lastname: Dap
authors.affiliation: Université de Toulouse; UPS, INPT; LAPLACE, 118 route de Narbonne, 31062 Toulouse Cedex 9, France and CNRS; LAPLACE; 31062 Toulouse, France.
authors.forename: K
authors.initials: K
authors.lastname: Makasheva
authors.affiliation: Université de Toulouse; UPS, INPT; LAPLACE, 118 route de Narbonne, 31062 Toulouse Cedex 9, France and CNRS; LAPLACE; 31062 Toulouse, France.
authors.forename: R
authors.initials: R
authors.lastname: Clergereaux
mesh_terms: D017357:Cyclotrons; D004583:Electrons; D006358:Hot Temperature; D008872:Microwaves; D009356:Neon; D058626:Plasma Gases; D011336:Probability; D013057:Spectrum Analysis
chemical_list: D058626:Plasma Gases; D009356:Neon