Kinetic Simulation of Electron Transport Properties and Radical Yields in Nitrogen-Trifluoride Discharges

International Journal of Physics | Vol. 9, No. 6, June 2018 | pp. 41–48

DOI: 10.46882/2018/IJP/000098

Research Article

Title: Kinetic Simulation of Electron Transport Properties and Radical Yields in Nitrogen-Trifluoride Discharges

Names of Authors: A. M. El-Chemali¹, S. H. Zhang²

Authors’ Affiliations: ¹Department of Physics, Faculty of Science, Lebanese University, Beirut, Lebanon; ²Department of Physics, Tsinghua University, Beijing, China

Abstract: Nitrogen trifluoride (NF3) gas discharges are widely utilized in plasma processing reactors for chamber cleaning and silicon nitride thin-film etching. This study develops a self-consistent kinetic simulation model to analyze electron transport properties and compute radical generation rates in low-pressure NF3 discharges. We solved the electron Boltzmann equation using a multi-term spherical harmonic expansion scheme across a reduced electric field range (E/N) from 10.0 Td to 600.0 Td. The model incorporates comprehensive cross-section sets, including elastic scattering, vibrational excitation, dissociative attachment, and direct impact ionization processes. Our modeling results show that adding nitrogen diluents (from 10.0% to 50.0% by volume) drastically distorts the electron energy distribution function. At a field strength of E/N = 80.0 Td, the total fluorine radical production rate coefficient increases by over an order of magnitude due to shifting electron mean energies. This enhancement accelerates chemical etching paths during processing. The calculated electron drift velocities and longitudinal diffusion coefficients match independent swarm experimental measurements within a ±4.5% variance. These kinetic parameters provide essential baseline input data for optimizing industrial semiconductor chamber performance.

Keywords: Nitrogen trifluoride; Boltzmann equation; electron transport; plasma kinetics; cross-section; semiconductor etching

Manuscript Timeline: Received: February 15, 2018; Revised: April 12, 2018; Accepted: May 04, 2018; Published: June 15, 2018

Citation: El-Chemali, A. M., & Zhang, S. H. (2018). Kinetic Simulation of Electron Transport Properties and Radical Yields in Nitrogen-Trifluoride Discharges. International Journal of Physics, 9(6), 41–48.

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