Analysis of uncertainty in measurement of electron temperature in low-pressure inductively coupled plasmas using microwave cutoff probe

Abstract

In this study, we performed electron temperature measurements by using a square cutoff probe. Further, the measurement uncertainty was comprehensively analysed. The square cutoff probe allows for the measurement of the electron temperature based on the measured electron series resonance frequency and that of the electron plasma frequency based on the transmission spectrum of the plasma. The electron temperatures were determined under varying gas pressures and input power conditions, and the results were compared with those obtained using a single Langmuir probe. Also, the impact of electron-neutral collision frequency on electron temperature measurement using square cutoff probe was analyzed based on a plasma equivalent circuit model. The square cutoff probe is expected to serve as a valuable diagnostic tool for the precise characterisation of electron temperature, offering localised, accurate, and easily interpretable features.