Dresden 2017 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 79: Poster: New Materials
HL 79.18: Poster
Donnerstag, 23. März 2017, 15:00–19:00, P2-OG3
Transmission Electron Microscopy investigations on structural origins of cross hatching in Si1−xGex/Si — Florian Biebl, •Elisabeth Anna Zolnowski, Felix Schwarzhuber, Christian Neumann, Michaela Trottmann, Dominique Bougeard, and Josef Zweck — Institute of Experimental and Applied Physics, University of Regensburg, Germany
The occurrence of cross-hatched surfaces can be observed under certain growth conditions in various strain engineered semiconductor materials. This means, that a surface shows periodic ridges and trenches along specific growth directions. This phenomenon influences the electron mobility and other properties of the grown materials. Therefore, it is important to understand the origin of the cross-hatch pattern (CHP) in order to prevent unwanted effects in semiconductor devices. By Transmission Electron Microscopy (TEM) we investigated CHPs on epitaxially grown strain-relaxed Si1−xGex/Si by molecular beam epitaxy, prepared as a cross section specimen along a periodic direction of the CHP. The periodicity and depth of the CHP observed in our measurements are in good agreement with literature [1]. Further, we could show that there is a correlation between the occurrence of a trench and a so called 60∘ dislocation originating in the substrate. In addition, we will present results of nanodiffraction experiments, revealing that these dislocations may separate areas of slightly different crystallographic orientations.
[1] Lutz et al., Influence of misfit dislocations on the surface morphology of Si1−xGex films, Applied Physics Letters 66, 724 (1995)