Investigation of the high-frequency glow discharge in Ar at 13.56 MHz by spatiotemporal optical emission spectroscopy

The radio frequency glow discharge in Ar at 13.56 MHz has been investigated by using time- and space-resolved emission spectroscopy with a resolution of 0.2 ns. The relative net excitation rate is also obtained by deconvoluting the emission profile considering the effect of the lifetime. From these results, the authors are able to guess the electron transport and the temporal structure of the discharge. ArI(3p₅to 1s₄), ArI(2p₂to 1s₅) and ArII(4p⁴D_7/2to 4s⁴P_5/2) lines are selected for observation. The electrons with low energy, epsilon >14.57 eV, are transported corresponding to the phase of the current. The electrons with higher energy, M>35.05 eV, are observed at the phase corresponding to the applied voltage only when the aluminium electrode is used under the present experimental conditions. It is confirmed that the high-energy electrons are secondary electrons emitted from the electrode. The RF discharge in Ar at 13.56 MHz has two modes with a hysteresis loop as the function of input energy.