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Ion-Enhanced Etching of Si(100) With Molecular Chlorine: Reaction Mechanisms and Product Yields

Published

Author(s)

R S. Goodman, N Materer, S R. Leone

Abstract

Laser single-photon ionization time-of-flight mass spectrometry is used to measure silicon etch products that evolve during argon ion-enchanced etching of room temperature Si(100) with molecular chlorine over an ion energy range of 275-975 eV. The etch products are examined as a function of ion energy, ion flux, and molecular chlorine flux. The neutral Si atom, SiCl, and SiCl2 are the only product species observed with the 118 nm ionization and are detected directly without fragmentation. The Si and SiCl species are the main products, with the latter having much greater yield. The yield of each product increases with increasing ion energy. The SiCl/Si yield ratio increases with decreasing ion kinetic energy, indicating an increase in the chlorine surface coverage at lower ion energies. A simple kinetic model, including chlorine adsorption and sputtering of the resulting silicon chloride surface moieties, is proposed to describe the formation fo Si and SiCl etch products. A model describing the chlorine pressure dependence of Si atom sputtering is developed in which the sputtering of Si atoms occurs from two different precursor states, one from an unchlorinated site and another from a partially chlorinated site. Using this kinetic model, the sputtering yield for SiCl per Ar+ is estimated from the molecular chlorine flux dependence of the SiCl signals and ranges from 3.2 0.8 to 4.9 0.9.
Citation
Journal of Vacuum Science and Technology
Volume
17
Issue
No. 6

Keywords

argon, chlorine, enhanced, etching, ion, silicon

Citation

Goodman, R. , Materer, N. and Leone, S. (1999), Ion-Enhanced Etching of Si(100) With Molecular Chlorine: Reaction Mechanisms and Product Yields, Journal of Vacuum Science and Technology (Accessed April 19, 2024)
Created November 30, 1999, Updated October 12, 2021