Production and loss mechanisms of SiCl{sub X} etch products during silicon etching in a high density HBr/Cl{sub 2}/O{sub 2} plasma

Journal Article · Fri Oct 15 00:00:00 EDT 2004 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.1786338· OSTI ID:20662122

Cunge, G; Kogelschatz, M; Sadeghi, N ^[1]

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1. Laboratoire des Technologies de la Microelectronique, CNRS 17 rue des Martyrs (CEA-LETI) 38054 Grenoble Cedex 9 (France)

SiCl{sub X} (X=0-2) radicals' concentrations have been measured by broadband ultraviolet absorption spectroscopy during the etching of 200 mm diameter silicon wafers in HBr/Cl{sub 2}/O{sub 2} plasmas. We report the variations of the concentrations of these radicals as a function of the radio frequency (rf) source power and rf-bias power. The silicon wafer etch rate is measured simultaneously. From the measured radicals densities and using electron impact ionization cross sections found in the literature, the densities of SiCl{sub X}{sup +} ions are calculated and are found to be in good agreement with ion densities measured by mass spectrometry. The upper limit for the SiCl{sub 2} radical concentration is calculated from the wafer etch rate. By comparison with the measured SiCl{sub 2} radical concentration it is concluded that SiCl{sub 2} radicals should also be produced by the reactor walls due to the etching of silicon containing species adsorbed on the reactor walls. Finally, using electron impact dissociation cross sections, the densities of SiCl and Si are calculated from the measured densities of SiCl{sub 2} and SiCl, respectively. The comparison between the calculated and measured values of SiCl{sub X} densities allowed us to conclude that SiCl (and Si) are produced both in the gas phase by electron impact dissociation of SiCl{sub 2} (SiCl) radicals and at the reactor wall surfaces by the neutralization and reflection of {approx_equal}50% of the flux of SiCl{sup +} (Si{sup +}) ions impinging on these surfaces. At the same time SiCl and Si are estimated to be lost (adsorption and abstraction reactions) on the reactor walls with a probability ranging between 0.2 and 1.

• OSTI ID: 20662122
• Journal Information: Journal of Applied Physics, Vol. 96, Issue 8; Other Information: DOI: 10.1063/1.1786338; (c) 2004 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
ABSORPTION SPECTROSCOPY
ADSORPTION
CHLORINE
CROSS SECTIONS
DISSOCIATION
ETCHING
HYDROBROMIC ACID
ION DENSITY
IONIZATION
MASS SPECTROSCOPY
PLASMA DENSITY
PLASMA PRODUCTION
RADICALS
RADIOWAVE RADIATION
SEMICONDUCTOR MATERIALS
SILICON
SILICON CARBIDES
SILICON CHLORIDES
ULTRAVIOLET RADIATION
ULTRAVIOLET SPECTRA