No abstract

A combined spectroscopic method of absorption, actinometry, and relative optical emission intensity is employed to determine the absolute CF 2 density, the relative F and H densities, H atom excitation temperature and the electron density in dual-frequency (60/2 MHz) capacitively coupled CHF 3 /Ar plasmas. The effects of different control parameters, such as high-frequency (HF) power, low-frequency (LF) power, gas pressure, gap length and content of CHF 3 , on the concentration of radical CF 2 , F, and H and excitation temperature are discussed, respectively. It is found that the concentration of CF 2 is strongly dependent on the HF power, operating pressure and the proportion of CHF 3 in feed gas, while it is almost independent of the LF power and the gap length. A higher concentration ratio of F to CF 2 could be obtained in dual-frequency discharge case. Finally, the generation and decay mechanisms of CF 2 and F were also discussed. V C 2013 AIP Publishing LLC.