Metal-on-Metal Heteroepitaxy and the Influence of a Surfactant: Cu/O/Ru(0001)

  • H. Wolter
  • M. Schmidt
  • M. Nohlen
  • K. Wandelt
Chapter

Abstract

Cu-on-Ru(OOOl) has been a suitable model system for metal-on-metal heteroepitaxy for many years because of the immiscibility of the two components. In contrast to most ex-situ studies the present work emphasizes dynamical work function change (ΔØ) measurements using a special KELVIN-capacitor probe as being a sensitive method to monitor the film morphology in-situ , that is during film growth. In particular, it is demonstrated that preadsorbed oxygen on the Ru(0001) substrate permanently “floats out” to the Cu surface and acts as a surfactant for layer-by- layer growth at a temperature of 400 K, at which in the absence of oxygen non-ergodic growth leads to the formation of pyramidal clusters and, hence, a very rough film. The mechanistic influence of the surfactant oxygen is discussed in detail and may certainly be carried over to other metal-on-metal systems.

Keywords

Work Function Thin Metal Film Step Atom Work Function Change Rough Film 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
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References

  1. [1]
    G. Ehrlich and F.G. Hudda, J. Chem. Phys. 44, 1039(1966)CrossRefGoogle Scholar
  2. [2]
    R.L. Schwoebel and E.J. Shipsey, J. Appl. Phys. 37, 3682(1966)CrossRefGoogle Scholar
  3. [3]
    E. Bauer, Appl. Surf. Sci., 11/12, 479(1982)CrossRefGoogle Scholar
  4. [4]
    R. Kern, G. Lelay and J.J. Metois:Basic Mechanisms in the Early Stages of Epitaxy, Chapter 3, in Current Topics in Material Science, Vol. 3 (North-Holland, Amsterdam, 1979)Google Scholar
  5. [5]
    W.F. Egelhoff, Jr. and D.A. Steigerwald, J. Vac. Sci. Technol. A7, 2167(1989)Google Scholar
  6. [6]
    M. Copel, M.C. Reuter, E. Kaxiras and R.M. Tromp, Phys. Rev. Lett. 63, 632(1989)CrossRefGoogle Scholar
  7. [7]
    J. Vrijmoeth, H.A. van der Vegt, J.A. Meyer, E. Vlieg and R.J. Behm, Phys. Rev. Lett. 72, 3842(1994)CrossRefGoogle Scholar
  8. [8]
    S. Esch, M. Hohage, T. Michely and G. Comsa, Phys. Rev. Lett. 72, 518(1994)CrossRefGoogle Scholar
  9. [9]
    H. Wolter, M. Schmidt and K. Wandelt, Surf. Sci. 298, 173(1993)CrossRefGoogle Scholar
  10. [10]
    M. Schmidt, H. Wolter and K. Wandelt, Surf. Sci. 307–309, 507(1994)CrossRefGoogle Scholar
  11. [11]
    M. Schmidt, H. Wolter, M. Nohlen and K. Wandelt, J. Vac. Sci., Technol. A12, 1818(1994)Google Scholar
  12. [12]
    M. Henzler, Prog. Surf. Sci. 42, 297(1993)CrossRefGoogle Scholar
  13. [13]
    J.M. Van Hove, C.S. Lent, P.R. Pukite and P.I. Cohen, J. Vac. Sci. Technol. B1, 741(1983)Google Scholar
  14. [14]
    J.E. Parmeter, R. Kunkel, B. Poelsema, L.K. Verheij and G. Comsa, Vacuum 41, 467(1990)CrossRefGoogle Scholar
  15. [15]
    H.A. van der Vegt, J.M.C. Thornton, H.M. van Pinxteren, M. Lohmeier and E. Vlieg, Phys. Rev. Lett. 68, 3335(1992)CrossRefGoogle Scholar
  16. [16]
    J. Hölzl, G. Porsch and P. Schrammen, Surf. Sci. 97, 529(1980)CrossRefGoogle Scholar
  17. [17]
    K. Besocke and S. Berger, Rev. Sci. Instrum. 47, 840(1976)CrossRefGoogle Scholar
  18. [18]
    R. Smoluchowski, Phys. Rev. 60, 661(1941)CrossRefGoogle Scholar
  19. [19]
    B. Krahl-Urban, E.A. Niekisch and H. Wagner, Surf. Sci. 64, 52(1977)CrossRefGoogle Scholar
  20. [20]
    K. Wandelt, in Chemistry and Physics of Solid Surfaces VIII, Vol. 22 of Springer Series in Surface Science, Eds. R. Vanselow and R. Howe (Springer, Heidelberg, 1990) p. 314CrossRefGoogle Scholar
  21. [21]
    K. Wandelt, in Thin Metal Films and Gas Chemisorption, Ed. P. Wissmann, Vol. 32 of Studies in Surface Science and Catalysis (Elsevier, Amsterdam, 1987) p. 280Google Scholar
  22. [22]
    K. Kalki, M. Schick, G. Ceballos and K. Wandelt, Thin Solid Films 228, 36(1993)Google Scholar
  23. [23]
    K. Christmann, G. Ertl and H. Shimizu, J. Catal. 61, 397(1980)CrossRefGoogle Scholar
  24. [24]
    J.C. Vickermann, K. Christmann, G. Ertl. P. Heimann, F.J. Himpsel and D.E. Eastman, Surf. Sci. 134, 367(1983)CrossRefGoogle Scholar
  25. [25]
    C. Park, E. Bauer and H. Poppa. Surf. Sci. 187, 86(1987)CrossRefGoogle Scholar
  26. [26]
    J.E. Houston, C.H.F. Peden, D.S. Blair and D.W. Goodman, Surf. Sci. 167, 427(1986)CrossRefGoogle Scholar
  27. [27]
    K.S. Kim, J.H. Sinfelt, S. Eder, K. Markert and K. Wandelt, J. Phys. Chem. 91, 2337(1987)CrossRefGoogle Scholar
  28. [28]
    H. Tochihara, G. Rocker, M. Martin and T. Yates, Surf. Sci. 203, 44(1988)CrossRefGoogle Scholar
  29. G. Pötschke, J. Schröder, C. Günther, R.Q. Hwang and R.J. Behm, Surf. Sci. 251/252, 592(1991)CrossRefGoogle Scholar
  30. [30]
    G. Pötschke and R.J. Behm, Phys. Rev. B44, 1442(1991)Google Scholar
  31. [31]
    M. Schmidt, Diplom-thesis, University Bonn, 1992Google Scholar
  32. [32]
    K. Kalki, PhD-thesis, University Bonn, 1992Google Scholar
  33. [33]
    J. Schäfer, P. Reinhardt, H. Hoffschulz and K. Wandelt, Surf. Sci. 313, 83(1994)CrossRefGoogle Scholar
  34. [34]
    C. Günther and R.J. Behm, private communicationGoogle Scholar
  35. [35]
    The deposition time per period of the oscillations is, indeed, 11% longer than the deposition time to reach the first knee in a ΔØ-curve at 640 K on bare Ru [9]. This is in perfect agreement with the reduced atomic density of the first pseudomorphic layer compared to a perfect Cu(lll) plane.Google Scholar
  36. [36]
    There is, of course, no equilibrium between the surface and the 3D vapor phase. The fact that the film grows is a consequence of non-equilibrium, namely of a supersaturation of the Cu vapor phase at the given substrate temperature. However, if reevaporation of Cu atoms into the gas phase is negligible one can still speak of equilibrium or non-equilibrium conditions within the 2D adsorbed layer onlyGoogle Scholar
  37. [37]
    C.S. Fadley, S. Kono, J.T. Lloyd and K.A. Thompson, Proc. 4th ICSS & 3rd ECOSS (Cannes, 1980) Suppl. Le Vide, Les Couches Minces, No. 201, Vol. 1, p. 665Google Scholar
  38. [38]
    M.A. Van Hove in:Nature of the Surface Chemical Bond“, Eds. T. Rhodin, G. Ertl (North-Holland, Amsterdam, 1979)Google Scholar
  39. [39]
    G. Ehrlich, Surf. Sci. 331–333, 865(1995)CrossRefGoogle Scholar
  40. [40]
    Landolt-Bornstein, Zahlenwerte und Funktionen, 6. ed., Vol. 4, Part 2b, p. 685Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1996

Authors and Affiliations

  • H. Wolter
    • 1
  • M. Schmidt
    • 1
  • M. Nohlen
    • 1
  • K. Wandelt
    • 1
  1. 1.Institut für Physikalische und Theoretische ChemieUniversität BonnBonnGermany

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