Spatio-temporal measurements Ar 2p₁ excitation rates and optical emission spectroscopy by capacitively coupled Ar and Ne mixed gas plasma

We investigated the Ar mixture ratio dependence of the high-energy electron behaviors in capacitively coupled Ar+Ne plasmas using Optical Emission Spectroscopy (OES) and Phase-Resolved Optical Emission Spectroscopy (PROES) methods. OES measurements showed that optical emission intensities of Ar and Ne decreased as Ar mixture ratio increased, which implied decreases in the excitation rates of Ar and Ne. The spatio-temporal distribution of the Ar I 2p₁ excitation rate was measured using the PROES method. These measurements showed the Ar I 2p₁ excitation rate decreased as the Ar mixture ratio increased, which was consistent with the OES results. These results implied that the collision frequency between electrons and neutral particles increased with increase in Ar mixture ratio. In addition, the sheath expansion width in one RF cycle became small with increasing Ar mixture ratio, which led to a weakening of the effect of stochastic heating and a decrease of the electron temperature. Graphical abstract: [Figure not available: see fulltext.]