Optical emission diagnostics with electric probe measurements of inductively coupled Ar/O2/Ar-O2 plasmas

Physical properties of low-pressure inductively coupled argon, oxygen, and Ar-O2 mixture plasmas are investigated using optical emission spectroscopy (OES) combined with an rf-compensated Langmuir probe measurement. In each gas discharge, the electron density and the electron temperature were obtained by using the probe. The electron temperature was also obtained by OES models and compared with that measured by the probe. The electron temperature was observed to decrease with increasing power and pressure and also observed to decrease with increasing Ar content. Argon metastable densities were calculated based on an optical transition model. In Ar-O2 discharges, the dissociation fraction of O2 molecules was estimated using optical emission actinometry. The dissociation fraction was observed to increase with increasing power and Ar content.