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O: Oberflächenphysik
O 5: Epitaxie und Wachstum I
O 5.1: Vortrag
Montag, 8. März 2004, 11:15–11:30, H44
Growth dynamics of Ge islands on high index Si surfaces — •Marcel Himmerlich1,2, Woochul Yang1, Robert J. Nemanich1, and Juergen A. Schaefer2 — 1Department of Physics, North Carolina State University, Raleigh, NC 27695 — 2Institut für Physik and Zentrum für Mikro- und Nanotechnologien, TU Ilmenau, 98684 Ilmenau
The growth dynamics of Ge islands on Si substrates with surface orientation close to (113) has been studied in situ by photoelectron emission microscopy (PEEM) at 450∘-550∘C and during annealing up to 700∘C. The growth rate was varied between 0.1 and 0.6 ML/min. Photoelectrons were excited by UV-light generated by the UV free electron laser at Duke University. First, up to 3-4ML, uniform emission was observed indicating the growth of a strained wetting layer. Then 3D-growth occurred with different island shapes. Low growth rates result in elongated islands in [332] direction, indicating anisotropical strain. At higher deposition rates round islands were created. There, during continuous deposition, islands enlargement was observed with no further nucleation. During annealing, the density of round islands decreased while the average size increased (ripening), whereas the elongated structures undergo a shape transformation leading to indentations.