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Temperature-Dependent Strain Relaxation and Islanding of Ge/Si(111)

Published online by Cambridge University Press:  10 February 2011

P. W. Deelman ,
L. J. Schowalter  and
T. Thundat
P. W. Deelman
Affiliation:
Rensselaer Polytechnic Institute, Troy, NY 12180{pdeelman, schowalt}@unix.cie.rpi.edu
L. J. Schowalter
Affiliation:
Rensselaer Polytechnic Institute, Troy, NY 12180{pdeelman, schowalt}@unix.cie.rpi.edu
T. Thundat
Affiliation:
Oak Ridge National Laboratory, Oak Ridge, TN 37831, [email protected]
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Abstract

In order to understand Ge island nucleation and evolution, we have studied strain relaxation and clustering of Ge grown on Si(111) by molecular beam epitaxy (MBE) with in situ reflection high energy electron diffraction (RHEED), atomic force microscopy (AFM), and Rutherford backscattering spectrometry (RBS). Our goal is to tailor the size and density of the nanocrystals by controlling thermodynamics and kinetics. At low temperature (∼ 450°C), we observe a sharp 2D–3D growth mode transition after 2.5ML ±0.1ML (we define a thickness of 1ML to be one-third the length of the body diagonal of the Ge conventional unit cell), when transmission diffraction features appear in RHEED and the surface lattice constant begins to relax. The mechanisms of island growth and strain relaxation change with growth temperature. At ∼ 700°C, transmission diffraction spots never appear in RHEED for Ge/Si(111) and strain relaxation occurs gradually. After 37ML of growth, the apparent in-plane lattice parameter increases only 1.5% over that of the Si substrate. This behavior is explained by the different manner in which islands initially nucleate and grow in the two temperature regimes. At low temperature, small islands nucleate and grow on a relatively rough wetting layer (which itself provides preferential sites for dislocation introduction). The areal density of the small islands is relatively high. At high temperature, a small number of islands grow very large from the outset. A general model indicates how, at low temperature. The relative difficulty of overcoming the barrier to dislocation formation actually results in an apparent larger degree of strain relief than at high temperature.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 417: Symposium EE – Optoelectronic Materials-Ordering, Composition Modulation, and Self-Assembled … , 1995 , 227
Copyright
Copyright © Materials Research Society 1996

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References

[1] Gossmann, H.-J. and Feldman, L.C.. Molecular beam epitaxy and reconstructed surfaces. Appl. Phys. A, 38:171–179, 1985.Google Scholar
[2] Deelman, P.W., Thundat, T., and Schowalter, L.J.. Ge Nanocrystals Grown On Si(111) By Molecular Beam Epitaxy With And Without CaF2 Buffer Layers. Mat. Res. Soc. Symp. Proc., 358, 1995.Google Scholar
[3] Deelman, P.W., Thundat, T., and Schowalter, L.J.. AFM and RHEED Study of Ge Islanding on Si(111) and Si(100). Appl. Surf. Sci., in press.Google Scholar
[4] Eaglesham, D.J. and Cerullo, M.. Phys. Rev. Lett., 64:1943, 1990.Google Scholar
[5] Snyder, C.W., Orr, B.G., Kessler, D., and Sander, L.M.. Effect of strain on surface morphology in highly strained InGaAs films. Phys. Rev. Lett., 66(23):3032–3035, June 10 1991.Google Scholar
[6] Leonard, D., Krishnamurthy, M., Reaves, C.M., Denbars, S.P., and Petroff, P.M.. Direct formation of quantum-sized dots from uniform coherent islands of InGaAs on GaAs surfaces. Appl. Phys. Lett., 63(23):3203–3205, December 1993.Google Scholar
[7] Chu, W.K., Mayer, J.W., and Nicolet, M.A.. Backscattering Spectrometry. Academic Press, 1978.Google Scholar
[8] Bauer, E.. Reflection Electron Diffraction (RED). In Bunshah, R.F., editor, Techniques for the Direct Observation of Structure and Imperfections, volume 2 of Techniques of Metals Research, chapter 15, pages 501–558. Interscience Publishers, 1969.Google Scholar
[9] Kern, W.. RCA Engineer, 28:99, 1983.Google Scholar
[10] Theiss, S.K., Chen, D.M., and Golovchenko, J.A.. Three-stage relaxation of Ge islands on Si(111) measured by tunneling microscopy. Appl. Phys. Lett., 66(4):448–450, January 23 1995.Google Scholar
[11] Voigtlander, B. and Zinner, A.. Simultaneous molecular beam epitaxy growth and scanning tunneling microscopy imaging during Ge/Si epitaxy. Appl. Phys. Lett., 63(22):3055–3057, November 1993.Google Scholar
[12] Kohler, U., Jusko, O., Pietsch, G., Muller, B., and Henzler, M.. Strained-layer growth and islanding of germanium on Si(111)-7 × 7 studied with STM. Surf. Sci, 248:321–331, 1991.Google Scholar
[13] Gossmann, H.-J., Bean, J.C., Feldman, L.C., McRae, E.G., and Robinson, I.K.. Phys. Rev. Lett., 55:1106–1109, 1985.Google Scholar
[14] LeGoues, F.K., Hammar, M., Reuter, M.C., and Tromp, R.M.. In-situ TEM study of the growth of Ge on Si(111). Surf. Sci. (in press).Google Scholar
[15] LeGoues, F.K., Tersoff, J., Reuter, M.C., Hammar, M., and Tromp, R.. Relaxation mechanism of Ge islands/Si(001) at low temperature. Appl. Phys. Lett, 67(16):2317–2319, 16 October 1995.Google Scholar