Publication Date:
2014-10-04
Description:
Broadband ultraviolet absorption spectroscopy has been used to determine the CF 2 radical density in dual-frequency capacitively coupled CF 4 /Ar plasmas, using the CF 2 A ̃ 1 B 1 ← X ̃ 1 A 1 system of absorption spectrum. The rotational temperature of ground state CF 2 and excited state CF was also estimated by using A ̃ 1 B 1 ← X ̃ 1 A 1 system and B 2 Δ − X 2 Π system, respectively. The translational gas temperature was deduced from the Doppler width of the Ar * ( 3 P 2 ) and Ar * ( 3 P 0 ) metastable atoms absorption line by using the tunable diode laser absorption spectroscopy. The rotational temperatures of the excited state CF are about 100 K higher than those of ground state CF 2 , and about 200 K higher than the translational gas temperatures. The dependences of the radical CF 2 density, electron density, electron temperature, rotational temperature, and gas temperature on the high frequency power and pressure have been analyzed. Furthermore, the production and loss mechanisms of CF 2 radical and the gas heating mechanisms have also been discussed.
Print ISSN:
1070-664X
Electronic ISSN:
1089-7674
Topics:
Physics