Experimental and numerical analyses of electron temperature and density distributions in a magnetic neutral loop discharge plasma

In order to study the plasma structure and its application to processing, experimental and numerical analyses of the distribution of the electron temperature (Te) and electron density (ne) in a neutral loop discharge (NLD) plasma were performed. From the experiments, NLD plasma possesses Te and ne peaks. In the cases of NL radii of RNL=80, 100, and 120 mm, the maximum values measured for Te were around the NL. However, the ne peaks of the cases mentioned were located about 30–40 mm radially inward of the NL. We calculated the electron behavior in three dimensions to analyze these measured results, taking into consideration the actual experimental conditions such as the magnetic field, antenna position, and chamber walls. We found electrons are trapped in a region that is more inward of the NL due to a mirror field that causes the peak of ne. Also it is shown that good plasma uniformity could be obtained by dynamically controlling these Te and ne peaks.