Leveraging small scale electron density oscillations in RF plasmas to simplify hairpin resonator probe measurements

Abstract

Hairpin resonator probes have several design criteria that must be met in order for them to be an effective plasma diagnostic; one of the most important criteria is that they have a very high quality factor, typically Q > 100 or better.1 This criteria is so that the measured resonance can be resolved despite the presence of other chamber resonances and is able to be resolved when loading effects from secondary resonators, electron collisions, and transmission line poles contribute to the electrical characteristics of the probe. Even at these high Q-factors extraction of the resonant frequency can be difficult, particularly for larger industrial systems.