The fabrication of advanced devices increasingly requires materials with different properties to be combined in the form of monolithic heterostructures. In practice this means growing epitaxial semiconductor layers on substrates often greatly differing in lattice parameters and thermal expansion coefficients. With increasing layer thickness the relaxation of misfit and thermal strains may cause dislocations, substrate bowing and even layer cracking. Minimizing these drawbacks is therefore essential for heterostructures based on thick layers to be of any use for device fabrication. Here we prove by scanning X-ray nanodiffraction that mismatched Ge crystals epitaxially grown on deeply patterned Si substrates evolve into perfect structures away from the heavily dislocated interface. We show that relaxing thermal and misfit strains result just in lattice bending and tiny crystal tilts. We may thus expect a new concept in which continuous layers are replaced by quasi-continuous crystal arrays to lead to dramatically improved physical properties

Falub, C., Meduna, M., Chrastina, D., Isa, F., Marzegalli, A., Kreiliger, T., et al. (2013). Perfect crystals grown from imperfect interfaces. SCIENTIFIC REPORTS, 3 [10.1038/srep02276].

Perfect crystals grown from imperfect interfaces

MARZEGALLI, ANNA;MIGLIO, LEONIDA;
2013

Abstract

The fabrication of advanced devices increasingly requires materials with different properties to be combined in the form of monolithic heterostructures. In practice this means growing epitaxial semiconductor layers on substrates often greatly differing in lattice parameters and thermal expansion coefficients. With increasing layer thickness the relaxation of misfit and thermal strains may cause dislocations, substrate bowing and even layer cracking. Minimizing these drawbacks is therefore essential for heterostructures based on thick layers to be of any use for device fabrication. Here we prove by scanning X-ray nanodiffraction that mismatched Ge crystals epitaxially grown on deeply patterned Si substrates evolve into perfect structures away from the heavily dislocated interface. We show that relaxing thermal and misfit strains result just in lattice bending and tiny crystal tilts. We may thus expect a new concept in which continuous layers are replaced by quasi-continuous crystal arrays to lead to dramatically improved physical properties
Articolo in rivista - Articolo scientifico
X-Ray-Diffraction; Optical-Properties; Strain; Microscopy; Heteroepitaxy; Nanoscale; Nanowires; Epitaxy
English
2013
3
2276
none
Falub, C., Meduna, M., Chrastina, D., Isa, F., Marzegalli, A., Kreiliger, T., et al. (2013). Perfect crystals grown from imperfect interfaces. SCIENTIFIC REPORTS, 3 [10.1038/srep02276].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/46372
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