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An Interfacial Phase Transformation in CoSi2/Si(111)

Published online by Cambridge University Press:  25 February 2011

D.J. Eaglesham
Affiliation:
AT&T Bell Labs, 600 Mountain Avenue, Murray Hill, NJ 07974
R.T. Tung
Affiliation:
AT&T Bell Labs, 600 Mountain Avenue, Murray Hill, NJ 07974
R.L. Headrick
Affiliation:
AT&T Bell Labs, 600 Mountain Avenue, Murray Hill, NJ 07974
I.K. Robinson
Affiliation:
AT&T Bell Labs, 600 Mountain Avenue, Murray Hill, NJ 07974
F. Schrey
Affiliation:
AT&T Bell Labs, 600 Mountain Avenue, Murray Hill, NJ 07974
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Abstract

A new type of phase transformation at the interface is described in CoSi2/Si(111) B (i.e. twinned) epilayers. Thin (25Å) CoSi2 films are codeposited at room temperature on Si (111) with a Si-rich surface layer, and subsequently annealed. Plan-view transmission electron microscopy (TEM) shows that these films have low symmetry, the interface being characterised by a shift “R” between (220) planes in CoSi2 and Si. X-ray diffraction from “R” films differs from otherwise identical films either grown without Si-rich surface layer, or not annealed, which have the conventional cubic structure (“C”); R-CoSi2 cannot be indexed on a single reciprocal lattice. Cross-section high-resolution TEM suggests the presence of a separate (non-cubic) layer ≈9Å thick at the interface in these films. Annealing of R-CoSi2in-situ in the TEM shows a reversible transformation R⇔C occuring at temperatures varying from 180°C to 150K, depending on layer stoichiometry. Rt⇔C is thus a quasi-equilibrium, diffusionless transformation. We propose that R-CoSi2 lowers interfacial free energy for certain stoichiometries, but that bulk constraints stop the entire layer from transforming.

Type
Research Article
Copyright
Copyright © Materials Research Society 1990

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References

REFERENCES

[1] Tung, R.T. in Electron Microscopy Evaluation of Electronic Materials, NATO Adv. Workshop, Plenum Press, Ed. Cherns, D. (1988)Google Scholar
[2] Gibson, J.M., Bean, J.C., Poate, J.M., and Tung, R.T., Appl. Phys. Lett. 41, 818 (1982).Google Scholar
[3] Fischer, A.E.M.J., Vlieg, E., Veen, J.F. van der, Clausenitzer, M., and Materlik, G., Phys. Rev, B36, 4769, (1987).Google Scholar
[4] Zegenhagen, J., Huang, K.-G., Hunt, B.D., and Schowalter, L.J., Appl. Phys. Lett. 51, 1176 (1987).Google Scholar
[5] Hamann, D.R., Phys. Rev. Lett. 60, 313 (1988).Google Scholar
[6] Hoek, P.J. van der, Ravenek, W., and Baerends, E.J., Phys. Rev. Lett. 60, 1743 (1988).Google Scholar
[7] Rossi, G., Jin, X., Santaniello, A., DePadova, P., and Chandesris, D., Phys. Rev. Lett. 62, 191 (1989).Google Scholar
[8] Bulle-Lieuwma, C.W.T., Jong, A.F. de, Ommen, A.H. van, Veen, J.F. ven der, and Vrimoth, J., Appl. Phys. Lett. 55, 648 (1989).Google Scholar
[9] Robinson, I.K., Waskiewicz, W.K., Tung, R.T., and Bohr, J., Phys. Rev. Lett. 57, 2714 (1986).Google Scholar
[10] Jamieson, D.N., Bai, G., Kao, Y.C., Nieh, C.W., Nicolet, M.-A., and Wang, K.L., MRS Symp. Proc., 91, 479 (1987).Google Scholar
[11] Tung, R.T., Batstone, J.L., and Yalisove, S.M., J. Electrochem. Soc (1989), in press.Google Scholar
[12] Farrow, R.F.C., Robertson, D.S., Williams, G.M., Cullis, A.G., Jones, G.R., Young, I.M., and Davies, P.N.J., J. Cryst. Growth 54, 507 (1981).Google Scholar