Applications of infrared diode laser absorption spectroscopy to measurements of dissociation kinetics and calibration of actinometric optical emission spectroscopy

Dissociation kinetics of C2F6 was investigated using C2F6 measurements by the wavelength modulated infrared diode laser absorption spectroscopy in an inductively coupled, low-pressure, high-density plasma. Electron-impact dissociation rate constant of C 2F6 was determined in a parameter space where recombination reaction rate and residence time were both small.;The behavior of recombination reaction rate was investigated using the kinetic parameters experimentally obtained. Recombination reaction rate increased with residence time and reached a steady state, decreased with pressure, power, and H2 composition in the feed gas.;Recombination reaction rates obtained were further investigated in a plasma condition with high recombination. Reaction between a gas phase dissociation product and fluorocarbon species on the wall was proposed to be the recombination mechanism of C2F6. The concentration of the gas phase dissociation product, which recombine to C2F6, was calculated using the model.;A quantitative comparison of actinometric optical emission spectroscopy and the infrared diode laser absorption measurements of CF and CF2 was studied in an inductively-coupled plasma reactor. Actinometric measurements provides accurate relative concentrations for CF2 in the pressure range of 10--30 m Torr and the power range of 200--1000 W and are calibrated absolutely with the diode laser. On the other hand, actinometric measurements do not provide accurate relative concentrations for CF in the pressure range of 10--30 mTorr and the power range of 200--1000 W.