Spectroscopic measurement of the electron temperature and the metastable densities by using a simple collisional-radiative model in a low-pressure inductively-coupled argon plasma

Abstract

The electron temperature (T-e) and the metastable densities (n(1s3), n(1s5)) in inductively-coupled plasma (ICP) reactor in argon are investigated by using a spectroscopic method at various powers (100-1000 W) and pressures (2-50 mTorr). This spectroscopic method is based on the simple collisonal-radiative model caused by using the relative emission intensities of the special lines that originate from 4p levels. Moreover, this method requires a rate coefficient whose calculation relies on the accuracy of the electron excitation cross section. The electron temperatures obtained by using optical emission spectroscopy (OES) are compared with those obtained by using a Langmuir probe to establish their practical validity. Results show a close agreement in the pressure range of 10-20 mTorr. At the same time, the metastable densities are estimated and presented. The metastable densities (of the order of 10(10)-10(11) cm(-3)) increase with growing electron temperature.