O atom kinetics in RF CCP oxygen plasma at increased pressures

In this study, the 81 MHz symmetric CCP discharge in quartz tube at increased pressures (10 to 100 Torr) was used to study O$_{2}$ dissociation mechanism. The use of both spatially resolved and time-resolved actinometry technique on Kr in the modulated rf discharge allowed measuring atom loss frequency $\nu$$_{loss}$$^{O}$ and dissociation degree and thereby determining dissociation rate constant k$_{diss}$$^{O2}$. The O atom loss is connected with surface recombination at lower pressure and volume reactions at the higher pressure. The variation of plasma parameters allowed studying the O$_{2}$ dissociation and O atom loss mechanisms in a wide range of gas temperature from $\sim$ 500 K up to 1800 K. The possible mechanism of increasing k$_{diss}$$^{O2}$ at low E/N as well as the role of ozone generation in $\nu$$_{loss}$$^{O}$ is discussed in detail.