Characteristics of Pulsed Surface Wave Oxygen Plasma Generated by Ring-Slot Antenna

Abstract

Time-resolved probe and optical emission measurements were performed in the pulse modulated microwave oxygen plasma that was produced using a ring-slot antenna for surface wave mode. Microwave power (2.45 GHz, ˜1 kW max.) was modulated with a square wave pulse of 100 μs period and 20˜90 % duty ratio. Spatiotemporal evolution of an electron energy distribution function was obtained and the optical emission actinometry was used as a means for estimating relative concentrations of radicals in the plasma. These characteristics were compared with those of the continuously driven (CW) plasma.