Electron neutral collision frequency measurement with the hairpin resonator probe

Electron neutral collision frequency is measured using both grounded and floating hairpin resonator probes in a 27 MHz parallel plate capacitively coupled plasma. Operating conditions are 0.1–2 Torr (13.3–267 Pa) in Ar, He, and Ar–He gas mixtures. The method treats the hairpin probe as a two wire transmission line immersed in a dielectric medium. Measurements are obtained using a pressure and sheath correction process by sweeping over assumed collision frequencies in order to obtain the measured collision frequency. Results are compared to hybrid plasma equipment module simulations and show good agreement.