Investigation of plasma characteristics in a developed large-diameter, low-aspect ratio, radio frequency plasma source with a flat spiral antenna

A large-diameter, radio frequency (RF) plasma source with an inner diameter of 53.8 cm has been developed to evaluate high densification and the feasibility of such sources. This plasma source has a low aspect ratio with the source length shorter than the diameter. To evaluate the feasibility and plasma characteristics of this low-aspect-ratio device, preliminary measurements of plasma parameters, the electron energy probability function, and optical emission spectra were performed. The dependences on the RF input power and external magnetic field conditions suggest that inductively coupled plasma can be generated in the source. The results also indicate that suitable operational conditions for high-density plasma generation exist, which are related to the helicon wave dispersion relation under the available magnetic field strength.