Hostname: page-component-5c6d5d7d68-qks25 Total loading time: 0 Render date: 2024-08-06T18:49:34.560Z Has data issue: false hasContentIssue false

Diffuse Light Scattering as a Probe of Buried Interface Reactions

Published online by Cambridge University Press:  25 February 2011

V. Pantojas
Affiliation:
Physics Department and Center of Integrated Electronics Rensselaer Polytechnic Institute, Troy, NY 12180–3590
C. Cabral
Affiliation:
IBM T.J. Watson Research Center, Yorktown Heights, NY 10598.
J. Harper
Affiliation:
IBM T.J. Watson Research Center, Yorktown Heights, NY 10598.
P. D. Persans
Affiliation:
Physics Department and Center of Integrated Electronics Rensselaer Polytechnic Institute, Troy, NY 12180–3590
Get access

Abstract

We report the application of diffuse light scattering to study buried interface reactions. As a model system we discuss the annealing of thin Cu/Al bilayers. Samples were prepared by evaporating Cu/Al and Al/Cu bilayers onto SiO2 covered Si wafers at room temperature. The Cu-Al thickness ratio was chosen to yield an average composition of CuAIt. When bilayers are annealed at 200–250°C the scattering intensity increases by about a factor of five above the as-deposited samples. We believe that this increase is partially due to the non-uniform reaction at the Cu/Al interface and partially to the mottled surface formed when leading growing parts of the reaction layer reach the surface. The relative contribution from this scattering mechanism is discussed quantitatively. For higher annealing temperature(300–350°C) the scattered light intensity falls again almost to the original level, suggesting that the Al/Cu reaction is complete and that the surface is homogeneous and smooth. For higher temperature anneals (400–500°C) the scattering once again increases, mainly due to the natural monotonic increase in surface roughness when metals are annealed. Control samples of the pure metal on Si02 show only the high temperature roughening effect.

Type
Research Article
Copyright
Copyright © Materials Research Society 1991

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Ghate, P.B., Thin Solid Films 93, 359 (1982)Google Scholar
2. Roos, A., Bergkvist, M., and Ribbing, C.G., Appl. Opt., 27, 4314 (1988)Google Scholar
3. Campiasano, S.U., Costanco, E., and Scaccianoce, F., Thin Solid Films 52, 97 (1978)Google Scholar
4. Vandenberg, J.M. and Hamm, R.A., Thin Solid Films 97, 313 (1982)Google Scholar
5. Rajan, K. and Wallach, E.R., J. Cryst. Growth 49, 297 (1980)Google Scholar
6. Rayne, J.A., Shearer, M.P., and Bauer, C.L., Thin Solid Films 65, 381 (1980)Google Scholar
7. Murray, J.L., Int. Met. Rev., 30, 5 (1985)Google Scholar
8. Gershinskii, A.E., Fomin, B.I., Chorepov, E.E., and Edelman, F.L., Thin Solid Films, 42, 269 (1977)Google Scholar
9. Hentzell, H.T., Thompson, R.D., and Tu, K.N., J. Appl. Phys., 54, 12 (1983)Google Scholar
10. Church, E.L. and Zavada, J.M., Appl. Opt., 14, 1788 (1984)Google Scholar
11. Sommerfeld, A., Optics, Vol. 4 (Academic Press Inc., New York, 1964), p. 191.Google Scholar