A study of ion velocity distribution functions in processing plasmas produced by electron cyclotron resonance discharges

Abstract

Ion velocity distribution functions were measured using Doppler-shifted laser-induced fluorescence spectroscopy in an electron cyclotron resonance discharge in argon. The influence of the magnetic field configuration on the distributions was studied by making measurements with different magnetic field configurations. Results of a two-dimensional hybrid model of the discharge were used to help interpret the measured data. The results from the experiment and the simulation indicated that the magnetic field configuration had a strong influence on the ion velocity distribution functions. From the simulation it was concluded that the magnetic field configuration determined the axial distributions of plasma potential and electron density, and how these plasma parameters determined the ion velocity distribution function in the downstream region of the discharge.

Optical Diagnostics for Thin Film Processing

“…The electron density and often non-Maxwellian EEDF are obtained, respectively, from the intensity of collected light and the Doppler broadening caused by electron motion (94,95). Ion and neutral velocity distributions can also be made with such elastic (Rayleigh) scattering (96,97).…”

Two-dimensional simulation of an electron cyclotron resonance plasma source with power deposition and neutral gas depletion

“…Recent progress along these lines has been impressive and much more effort has been made to develop computer simulation models of ECR plasma sources. The kinetic model [4], the fluid models [5,6] and the hybrid model [7][8][9][10] in one or two dimensions have been presented sequentially. This paper discusses not only the change of plasma parameters such as plasma density and ionization rate with operation conditions, but also ion angle distribution function at the substrate surface in an extended ECR plasma source.…”

Simulation of ion transport in an extended electron cyclotron resonance plasma

“…Recently, some improvements such as the self-consistent treatment of neutral particle density and the inclusion of the influence of electronion collision have been taking into consideration by Wu 15 and Cronrath, 18 respectively. In these previous publications, [14][15][16][17][18] the microwave absorption is always assumed to be a fixed function of the magnetic field and does not depend on any plasma parameters. But in real experiments, the microwave absorption is strongly dependent on the local electron density and temperature, etc.…”