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Strain in epitaxial CoSi2 films on Si (111) and inference for pseudomorphic growth

Bai, Gang and Nicolet, Marc-A. and Vreeland, Thad, Jr. and Ye, Q. and Wang, K. L. (1989) Strain in epitaxial CoSi2 films on Si (111) and inference for pseudomorphic growth. Applied Physics Letters, 55 (18). pp. 1874-1876. ISSN 0003-6951. http://resolver.caltech.edu/CaltechAUTHORS:BAIapl89

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Abstract

The perpendicular x-ray strain of epitaxial CoSi2 films grown on Si(111) substrates at ~600 °C was measured at temperatures from 24 up to 650 °C. At 600 °C, the perpendicular x-ray strain is –0.86%, which is about the x-ray strain that a stress-free CoSi2 film on Si(111) would have at that temperature. This result shows that the stress in the epitaxial CoSi2 film is fully relaxed at the growth temperature. Strains in the film below the growth temperature are induced by the difference in the thermal expansion coefficient of CoSi2 and Si, alphaf–alphas=0.65×10^–5/°C. Within experimental error margins, the strain increases linearly with decreasing temperature at a rate of (1.3±0.1)×10^–5/C. The slope of the strain-temperature dependence, obtained by assuming that the density of misfit dislocations formed at the growth temperature remains unchanged, agrees with the measured slope if the unknown Poisson ratio of CoSi2 is assumed to be nuf=1/3. These observations support three rules postulated for epitaxial growth.


Item Type:Article
Additional Information:Copyright © 1989 American Institute of Physics (Received 19 June 1989; accepted 24 August 1989) The authors would like to thank Dr. K. T. E. Keuch (IBM Corporation), Professor J. E. Mahen (Colorado State University), Dr. R. W. Fathauer (Jet Propulsion Laboratory) for helpful discussions, and Dr. Y. C. Kao (Texas Instruments Inc.) for providing some of the samples. This work was supported by the Semiconductor Research Corporation under contract No. 87-SJ-100.
Subject Keywords:STRAINS; COBALT SILICIDES; SILICON; X–RAY DIFFRACTION; HIGH TEMPERATURE; STRESSES; THERMAL EXPANSION; DISLOCATIONS; FILM GROWTH; EPITAXY; CRYSTAL STRUCTURE; EPITAXIAL LAYERS
Record Number:CaltechAUTHORS:BAIapl89
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:BAIapl89
Alternative URL:http://dx.doi.org/10.1063/1.102327
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:2663
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:14 Apr 2006
Last Modified:26 Dec 2012 08:50

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