Tuned electrostatic probe for RF plasma diagnostics

An electrostatic Langmuir probe with self-compensation for use in 13.56 MHz RF-plasmas has been implemented and characterized. A compensating electrode, as well as an RF choke circuit is embedded within the probe body, and tuned to suppress the 13.56 MHz fundamental frequency. Comparing results with a bare probe without any compensating circuit are reported. The characteristic curve obtained from the proposed probe shows a maximization of the plasma floating potential, V_f, indicating that the probe is well tuned and generating more reliable electrical parameters from the discharge, such as for the electron temperature, T_e.