Dresden 2003 – scientific programme

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O: Oberflächenphysik

O 22: Epitaxie und Wachstum I

O 22.2: Talk

Tuesday, March 25, 2003, 15:15–15:30, FOE/ORG

Influence of strain on surface diffusion. — •Vasily Cherepanov and Bert Voigtländer — Institut für Schichten und Grenzflächen, Forschungszentrum Jülich, 52425 Jülich, Germany

In recent years, the heteroepitaxial growth of lattice mismatched semiconductor systems, like Ge/Si, has attracted substantial interest due to new attractive perspective properties of strained films. Tensile or compressive stress has an important influence on the properties and surface morphology of the growing film. The surface reconstruction, which itself is a source of a strain, makes the situation more complicated. The measurement of the density of two-dimensional islands by Scanning Tunneling Microscopy after submonolayer growth is used to determine the strain dependence of surface diffusion. Templates of strained and relaxed Ge surface with the same surface reconstruction were prepared for comparison. The diffusion barrier for Ge and Si adatoms is founded to increase with increasing compressive strain of the Ge(111) substrate. When the strain increases from relaxed Ge to strained to the Si lattice constant, the diffusion barrier increases by ∼ 60 meV.