Diagnostic study and simulation of capacitive coupled RF plasma

Abstract

Aiming at the discharge characteristics of radio frequency capacitively coupled (CCRF) plasma at moderate pressure and medium power, a one-dimensional plasma discharge model was established by using COMSOL software based on fluid model. The distribution law in plasma electron temperature and electron density were studied at the same pressure and different radio frequency input power with Ar gas as working gas. At the same time, a closed glass cavity and a flat plate electrode of the same size were designed and fabricated according to the simulation model. The effective current, voltage and emission spectrum of the discharge plasma were measured experimentally at different RF input power. The electron temperature and electron density of the plasma were calculated by the current-voltage relationship and the energy balance equation. The electron temperature and electron density of plasma were obtained by Boltzmann double-wire method. When the gas pressure was 250 Pa and the input power was 100~450 W, the plasma voltage and current showed a linear relationship. The electron density increased with the increase of the power, but the electron temperature did not change with the change of the power. At the same time, the accuracy of the experiment was further verified by simulation. In this paper, the discharge parameters of plasma at moderate pressure are preliminarily diagnosed by combining the equivalent circuit method, spectral method and numerical simulation method, and a combination of these three methods is proposed for experiment to make the experimental results more convincing and to provide a basis for further study of plasma characteristics.