IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Electronics Wednesday Sessions
       Session EL-WeM

Paper EL-WeM5
Surface Mass Transport and Island Nucleation during Growth of Ge on Laser Textured Si(001)

Wednesday, October 31, 2001, 9:40 am, Room 124

Session: Si Surface Dynamics and Reactions
Presenter: D.G. Cahill, University of Illinois, Urbana
Authors: T. Schwarz-Selinger, Max Planck Institut für Plasmaphysik, Germany
D.G. Cahill, University of Illinois, Urbana
Correspondent: Click to Email
Shape transitions and coarsening of coherent three-dimensional islands in Stranski-Kranstanow crystal growth have been extensively studied but quantitative descriptions of island nucleation kinetics are hindered by incomplete understanding of surface mass transport on the wetting layer. To gain new insights on wetting layer mass transport, we manipulate the spatial distribution of island nucleation by modifying the substrate morphology with laser texturing: fluid flow in the melt zone created by tightly-focused nsec pulses from a frequency doubled Nd:YAG produces shallow, micron-sized dimples on the Si substrate. We then use gas-source molecular beam epitaxy to deposit Ge and, finally, measure the distribution of three-dimensional Ge islands surrounding the laser dimples by atomic force microscopy. As expected, island nucleation starts at the vicinal surfaces near the rim of the dimple. These initial islands create a denuded zone of suppressed island nucleation on the flat regions of the substrate surrounding the dimple. Nucleation theory predicts that the extent of the denuded zone L should be comparable to the the island-island separation d but, in the limit of slow growth rates, we observe L/d>20. By comparing the denuded zone lengths produced by different growth rates (varied by a factor of 100) and substrate temperatures (500-600°C), we extract an activation energy for surface mass transport.