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Proceedings Paper

Modeling of photochemical vapor deposition of epitaxial silicon using an ArF excimer laser
Author(s): Burt W. Fowler; Sean Lian; S. Krishnan; Le-Tien Jung; Chien-Yen Li; Sanjay K. Banerjee
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Paper Abstract

Low temperature silicon epitaxy has been achieved at substrate temperatures ranging from 250 degree(s)C to 350 degree(s)C using the 193 nm output of ArF excimer laser to generate reactive growth precursors by photolytic decomposition of Si2H6. Growth rate dependencies on substrate temperature, Si2H6 partial pressure, laser photon flux density, and beam-to-substrate distance are presented. A simple expression for the growth rate as a function of process parameters can be obtained by considering the single-photon absorption rate of Si2H6 at the ArF excimer laser wavelength of 193 nm, and the gas kinetic transport of the resulting photofragments to the substrate surface. With the beam tangentially positioned approximately 1 mm from the substrate, a large percentage (7 +/- 1%) of the silicon available from the excited Si2H6 contributes to film formation. As the beam is moved away from the substrate, the chemical reaction rate of the growth precursors becomes significant with respect to the diffusion rate and the growth rate is observed to decrease. By tilting the laser beam to provide a normally incident component striking the substrate surface, the dangling bond density of the surface can be increased by photon assisted H desorption and growth rates are observed to increase. At substrate temperatures less than 400 degree(s)C, the growth rate is weakly dependent on temperatures with an activation energy of approximately equals 0.05 eV, whereas for temperatures above 400 degree(s)C, film deposition becomes dominated by pyrolytic decomposition of Si2H6 with an activation energy of approximately equals 1.2 eV.

Paper Details

Date Published: 1 December 1991
PDF: 10 pages
Proc. SPIE 1598, Lasers in Microelectronic Manufacturing, (1 December 1991); doi: 10.1117/12.51031
Show Author Affiliations
Burt W. Fowler, Univ. of Texas/Austin (United States)
Sean Lian, Univ. of Texas/Austin (United States)
S. Krishnan, Univ. of Texas/Austin (United States)
Le-Tien Jung, Univ. of Texas/Austin (United States)
Chien-Yen Li, Univ. of Texas/Austin (United States)
Sanjay K. Banerjee, Univ. of Texas/Austin (United States)

Published in SPIE Proceedings Vol. 1598:
Lasers in Microelectronic Manufacturing
Bodil Braren, Editor(s)

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