Analytic description of the resonance frequencies of curling probe

Abstract

The term active plasma resonance spectroscopy (APRS) denotes a class of plasma diagnostic methods which utilizes the natural ability of plasmas to resonate on or near the electron plasma frequency: An electrical radio frequent signal (in the GHz range) is coupled into the chamber via an antenna or probe, the spectral response is recorded, and a mathematical model is used to determine plasma parameters such as the plasma density or the electron temperature. The curling probe, recently invented by Liang et al. [1], is a novel realization of APRS which has many practical advantages. In particular, it can be miniaturized, and it can be flatly embedded into the chamber wall, thus enabling monitoring or control of a plasma process without perturbing it.