Germanium segregation in the Co/SiGe/Si(001) thin film system

Peter T. Goeller, Boyan I. Boyanov, Dale E. Sayers, Robert Nemanich, Alline F. Myers, Eric B. Steel

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Cobalt disilicide contacts to silicon-germanium alloys were formed by direct deposition of pure cobalt metal onto silicon-germanium films on Si(001) substrates. Segregation of germanium was observed during the reaction of the cobalt with the silicon-germanium alloy. The nature of the Ge segregation was studied by transmission electron microscopy, energy dispersive spectroscopy, and x-ray diffraction. In the case of cobalt films deposited onto strained silicon-germanium films, the Ge segregation was discovered to be in the form of Ge-enriched Si1-xGex regions found at the surface of the film surrounding CoSi and CoSi2 grains. In the case of cobalt films deposited onto relaxed silicon-germanium films, the Ge segregation was dependent on formation of CoSi2. In samples annealed below 800 °C, where CoSi was the dominant silicide phase, the Ge segregation was similar in form to the strained Si1-xGex case. In samples annealed above 800 °C, where CoSi2 was the dominant silicide phase, the Ge segregation was also in the form of tetrahedron-shaped, Ge-enriched, silicon-germanium precipitates, which formed at the substrate/silicon-germanium film interface and grew into the Si substrate. A possible mechanism for the formation of these precipitates is presented based on vacancy generation during the silicidation reaction coupled with an increased driving force for Ge diffusion due to silicon depletion in the alloy layer.

Original languageEnglish (US)
Pages (from-to)4372-4384
Number of pages13
JournalJournal of Materials Research
Volume14
Issue number11
StatePublished - Nov 1999
Externally publishedYes

Fingerprint

Germanium
germanium
Silicon
Cobalt
Thin films
cobalt
thin films
silicon
germanium alloys
silicon alloys
Precipitates
precipitates
Substrates
tetrahedrons
Vacancies
Energy dispersive spectroscopy
depletion
x ray diffraction
Diffraction
Metals

ASJC Scopus subject areas

  • Materials Science(all)

Cite this

Goeller, P. T., Boyanov, B. I., Sayers, D. E., Nemanich, R., Myers, A. F., & Steel, E. B. (1999). Germanium segregation in the Co/SiGe/Si(001) thin film system. Journal of Materials Research, 14(11), 4372-4384.

Germanium segregation in the Co/SiGe/Si(001) thin film system. / Goeller, Peter T.; Boyanov, Boyan I.; Sayers, Dale E.; Nemanich, Robert; Myers, Alline F.; Steel, Eric B.

In: Journal of Materials Research, Vol. 14, No. 11, 11.1999, p. 4372-4384.

Research output: Contribution to journalArticle

Goeller, PT, Boyanov, BI, Sayers, DE, Nemanich, R, Myers, AF & Steel, EB 1999, 'Germanium segregation in the Co/SiGe/Si(001) thin film system', Journal of Materials Research, vol. 14, no. 11, pp. 4372-4384.
Goeller PT, Boyanov BI, Sayers DE, Nemanich R, Myers AF, Steel EB. Germanium segregation in the Co/SiGe/Si(001) thin film system. Journal of Materials Research. 1999 Nov;14(11):4372-4384.
Goeller, Peter T. ; Boyanov, Boyan I. ; Sayers, Dale E. ; Nemanich, Robert ; Myers, Alline F. ; Steel, Eric B. / Germanium segregation in the Co/SiGe/Si(001) thin film system. In: Journal of Materials Research. 1999 ; Vol. 14, No. 11. pp. 4372-4384.
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