Electrical characterization and modeling of a dust forming plasma in a radio frequency discharge

Abstract

In this article we focus on the time evolution of macroscopic and microscopic properties of a dust forming plasma in a silane–argon low pressure radio frequency (rf) discharge. The time evolution of electron density, ion density, dust particle concentration, and the current density were recorded in a low pressure (0.1 Torr) rf Ar–SiH4 discharge. From these data and optical emission spectroscopy simultaneous measurements, the time evolution of the electron mean energy and the particle mean charge are determined. Together with previous experimental data concerning the nucleation and growth of dust particles, a complete experimental set of microscopic and macroscopic data is available and it is compared to a theoretical model including both particle growth and dusty discharge parameters. A clear representation of this closely coupled time evolution of the particles’ formation and plasma properties is given. It includes the nucleation and coagulation phenomena for particles, and the strong increase of the rf electric field in the plasma volume and the increase of the excitation rates of electrons.