C 4 F 8 dissociation in an inductively coupled plasma

Abstract

A study of the dissociation of a small concentration of cyclic-C4F8 (c-C4F8) in a predominately argon, low pressure inductively coupled plasma is reported. Measurements of electron density, plasma potential, and electron energy distribution function (EEDF) were made at several pressures and over a range of dilute Ar/C4F8 plasmas using a Langmuir probe. The c-C4F8 concentration in the plasma was estimated using appearance potential mass spectrometry and ion mass spectrometry. Optical emission spectroscopy was used to estimate the gas temperature and total neutral number density. Volume-averaged total dissociation rate coefficients for c-C4F8 ionization and total dissociation into neutrals were calculated using reported cross sections and the measured EEDFs. Rate coefficients inferred by both methods were in agreement within experimental uncertainties and approximations of the model, indicating that the dissociation cross sections are accurate.