Effect of Surface Material on Spatiotemporal Structure in O₂ RF Glow Discharge

The influence of the electrode material on O 2 radio-frequency discharge structure is investigated using the relaxation continuum (RCT) model. The discharges considered in this study are self-sustained between parallel plates with spacing of 2 cm at 13.56 MHz. The spatiotemporal discharge structure for the pressure of 1.0 Torr and the sustaining voltage of 100–300sin ω t V is calculated. The results are discussed for two types of material differing in the surface recombination probability of atomic oxygen γ. When γ is changed from 0.015 to 0.001, the number density of atomic oxygen increases and the distribution has less spatial dependence. As a result, the rate of the electron detachment caused by the collision between O - and O increases, and the plasma density and the density ratio of the negative to positive ions decrease. The change of the material surface also affects the fluxes of positive ions and atomic oxygens to the electrode at a fixed sustaining voltage. The influence of the surface on the dissipated power is also discussed.