Regensburg 2000 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 12: Poster I: Quanten Hall Effekt (1-9), II-VI Halbleiter (10-17), Epitaxie (18-23), Quantenpunkte und -dr
ähte (24-50), Photonik (51-59), Metall-Isolator Übergang (60-64), Si/Ge (65-67), Elektronentheorie (68-69), Amorphe Halbleiter, Ionen-Implantation

HL 12.21: Poster

Montag, 27. März 2000, 14:00–19:00, A

MBE growth of Si:C rich layers and study of their relaxation — •P. Lavéant, G. Gerth, P. Werner, S. Senz, A. Plössl, and U. Gösele — Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle

The epitaxial growth of a thin Si layer with a carbon content of several percent on a Si substrate, i.e. 10⁴ time above its solubility limit in the Si lattice at melt temperature, can be realized by molecular beam epitaxy (MBE) . Since the substitutionally incorporated C atoms are smaller than the Si one, they induce high stresses in the Si lattice. Within a narrow temperature vs. C concentration window, the crystal growth stays two-dimensional. RHEED images as well as X-ray diffraction are able to spot such a compressed structure.

Using SOI wafers as substrates allows us, after HF etching of the SiO2 interlayer to release the grown Si:C layer from the substrate and then, as a consequence, to relax the lattice. Once the etching done, a bonding of the relaxed layer can be achieved. X-ray diffraction and TEM cross-sections has been used to analyze the Si/Si:C heterostructure as well as the related relaxation phenomena and the modified crystal lattice constant.