Radical and Molecular Product Concentration Measurements in CH₄ RF Plasmas by Infrared Tunable Diode Laser Absorption

Abstract

Infrared tunable diode laser absorption studies of radicals and stable molecules formed in radio frequency plasmas are being carried out in a laboratory reactor which allows a long absorption path.In this paper we describe studies of CH 4 RF plasmas.We report absolute concentration measurements as functions of total pressure and RF power for CH 3 and C 2 H 2 in CH 4 plasmas, as well as measurements of the CH 4 rotational temperature and dissociation fraction.