The method of ion current measurement on capacitive-coupled plasma

Abstract

A small device, the conduction current probe, has been developed for the multi-point observation of ion currents. The probes are mounted on an electrode of a capacitive-coupled rf plasma source. The probe obtains the conduction current entering the electrode as a function of time by shielding the rf displacement current. The conduction current consists of the ion current as well as the electron one. The ion current is nearly constant although the electron one synchronizes with the rf electric field and flows in the short time of a rf cycle. Therefore, the ion current is obtained from the constant region of the conduction current. The experiments on a rf magnetron have revealed that the probe is a useful device for studying the parametric properties of the plasma source.