Berlin 2008 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 10: Semiconductor Substrates: Epitaxy and Growth

O 10.10: Vortrag

Montag, 25. Februar 2008, 15:30–15:45, MA 042

Strain Induced Pit Formation in Ge Layers on Si(111) — •Konstantin Romanyuk¹, Vasily Cherepanov¹, Bert Voigtländer¹, and Jacek Brona^1,2 — ¹Institute of Bio- and Nanosystems (IBN 3), and cni – Center of Nanoelectronic Systems for Information Technology, Research Centre Jülich, 52425 Jülich, Germany — ²Institute of Experimental Physics, University of Wroclaw, pl. Maxa Borna 9, PL 50-204 Wroclaw, Poland

When nanoscale Ge stripes are grown at Si step edges by step flow growth the formation of nanoscale pits in the one atomic layer thick Ge stripes is observed. This pit formation occurs in surfactant mediated epitaxy (Bi) when a small amount of Si is deposited and attaches as a small rim at the Ge stripes. As we will explain this nanoscale pit formation is driven by both, the energy gain when Ge leaves the Ge stripe and attaches to the thin Si rim terminating the Ge stripe, and the entropy gain due to SiGe intermixing at the step edges. While the direct vertical exchange would lead to a similar final state a high exchange barrier is involved. The pathway via pit formation involves a much lower exchange barrier.