An improved model of the SEERS diagnostic method

Abstract

Summary form only given. The availability of a reliable and efficient method for monitoring the plasma electron density is mandatory for the practical realization of any closed-loop plasma control. In the past, however, diagnostic methods were either prohibitively expensive for any commercial use (e.g., microwave interferometry), provided only indirect information (such as bias voltage, reflected power, or optical emission intensity), or potentially disturbed the process plasma itself (Langmuir probes). SEERS, or self-excited electron resonance spectroscopy, is a novel diagnostic method that overcomes these limitations: It enables the real-time measurement of the electron density in RF driven plasma systems without any form of process contamination. Using the improved plasma model, a parameter study is presented which investigates the response of the SEERS signal to changes in the underlying system parameters, in particular the pressure and the composition of the gas, and the magnitude of the driving RF power. A comparison to experimental data is given.