Dielectric properties in microwave remote plasma sustained in argon : expanding plasma conditions

Jean-Louis Jauberteau (1) , Isabelle Jauberteau (1)

1 SPCTS-AXE2 - Axe 2 : procédés plasmas et lasers

This work is devoted to the study of the relative permittivity in argon expanding plasma produced below a microwave discharge sustained in a quartz tube and working at 2.45 GHz. We discuss results and explain the microwave propagation within the reactor, outside the quartz tube. It is shown that at low pressures (133 Pa) and at powers ranging from 100W to 400 W, the wave frequency remains lower than the plasma frequency anywhere in the expanding plasma. Under these conditions, the real part of the relative permittivity is negative and the wave is reflected. Surprisingly, in these conditions, the plasma is produced inside and outside the quartz tube, below the wave launcher. This effect can be explained considering a surface wave propagating at the surface of the quartz tube then into the reactor, on the external surface of the expanding plasma below the quartz tube.

Mots clés: Plasma wave; Permittivity; Quartz; Plasma expansion; Plasma diagnostics

Domaines: Physique des plasmas [physics.plasm-ph]; Plasmas

Jean-Louis Jauberteau, Isabelle Jauberteau. Dielectric properties in microwave remote plasma sustained in argon : expanding plasma conditions. Physics of Plasmas, 2012, 19 (11), pp.110701. ⟨10.1063/1.4766897⟩. ⟨hal-00771761⟩