Published online by Cambridge University Press: 22 February 2011
Laser-induced fluorescence (LIF) is an ideal technique to determine the gas phase concentration of the chemically reactive radical species in processing plasmas. Quantitative species concentration measurements require spectroscopic and collision dynamics data. Experiments to obtain such data for the B2 and Σ+ B′2 Δ states of SiCl are described. Using LIF, the transition strengths, radiative lifetimes, and collisional removal rates are determined. Collisional transfer between the two excited electronic states, B′→B, shows a very unusual quantum state specificity for the final vibrational levels which is quite different for each of the rare gas collision partners (He, Ne, Ar). Such energy transfer makes the B′2 Δ state unsuitable for quantitative LIF diagnostics; however, the B2Σ+ state appears to be an ideal excited state for LIF diagnostic measurements in silicon etching plasmas.