Characteristics of 1 MHz Discharge in SF 6/O 2 Mixture in a Parallel-Plate System

The influence that mixing SF6 with O2 has on the discharge characteristics varies with the pressure. At the total pressure of 0.5 Torr, the discharge structure changes remarkably and becomes almost the same as that of SF6 discharge by mixing only 5% SF6 with O2. At the total pressure of 0.1 Torr, the discharge-sustaining voltage, the discharge current and the spatiotemporal profile of optical emission do not vary noticeably by mixing only 5% SF6, though the radial distribution of plasma density changes clearly. In this case, the electronegativity of SF6 influences obviously on the discharge characteristics of SF6/O2 mixture at SF6 ratios greater than 50%.