Measurement of the CF3 radical using infrared diode laser absorption spectroscopy

Abstract

A measurement method for the CF3 radical using infrared diode laser absorption spectroscopy (IRLAS) was established. The CF2 radical density in a RF discharge CHF3 plasma was measured first. The obtained density was estimated to be of the order of 1013 cm-1 under the assumptions concerning the laser pathlength and radical temperatures. The spatial distribution of the CF3 radical density was almost uniform between the electrodes. Moreover, the CF3 and CF radical densities were measured as a function of H2 partial pressure, showing that the CF3 radical decreases with addition of H2 gas more rapidly than the CF radical.