Composition and strain in SiGe/Si(001) “nanorings” revealed by combined x-ray and selective wet chemical etching methods
| M. Stoffel, A. Malachias, A. Rastelli, T. H. Metzger, O. G. Schmidt Appl. Phys. Lett. 94, 253114 (2009) URL PDF |
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| Abstract | ||
| The authors used x-ray diffraction to investigate strain and composition in SiGe nanorings formed during partial Si capping of self-assembled SiGe/Si(001) islands. The obtained results are corroborated with selective wet chemical etching experiments. Clear evidence is provided that rings are composed of a Ge rich core surrounded by Si richer ridges indicating that a substantial material redistribution occurs during the shape transformation from SiGe islands to rings. The results suggest that SiGe ring formation is driven by strain relief. |