A numerical investigation of atomic oxygen density in an inductively coupled plasma in O2/Ar mixture

A numerical simulation of an inductively coupled plasma in an O2(<10%)/Ar mixture has been performed to investigate the production mechanisms and the spatial distribution of the atomic oxygen density. The O(3P) density is four times larger than that of O(1D) and much larger than the metastable molecular oxygen O(a1?g) density at 100?mTorr. The dominant mechanism of O(3P) production is electron quenching of O(1D) produced by dissociative excitation by electrons, and the net dissociation rate of O2 is one order of magnitude smaller than that of electron quenching of O(1D). However, quenching of O(1D) and excitation of O(3P) are found to be competitive processes under the present conditions. Both electron and Ar metastable (Ar*) density have the maxima at an O2 fraction of 1%, though Ar* has little effect on the production of O(3P) and O(1D) under the present high density plasma where Ar* is quenched by high density electrons and consumed.