Bending of nanoscale ultrathin substrates by growth of strained thin films and islands

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Publication Type Journal Article
School or College College of Engineering
Department Materials Science & Engineering
Creator Liu, Feng
Other Author Huang, Minghuang; Rugheimer, P.; Lagally, M. G.
Title Bending of nanoscale ultrathin substrates by growth of strained thin films and islands
Date 2005-08
Description Mechanical bending is ubiquitous in heteroepitaxial growth of thin films where the strained growing film applies effectively an "external" stress to bend the substrate. Conventionally, when the deposited film is much thinner than the substrate, the bending increases linearly with increasing film thickness following the classical Stoney formula. Here we analyze the bending of ultrathin (nanometer range) substrates induced by growth of coherently strained thin films. The behavior deviates dramatically from the classical linear dependence: when the film thickness becomes comparable to the substrate thickness the bending decreases with increasing film thickness. This complex bending behavior can be understood by considering evolution of strain sharing between the film and substrate. We demonstrate experimentally such counterintuitive bending of a nanoscale thin Si substrate induced by a coherently strained Ge film, in the form of islands, grown on silicon-on-insulator substrate. Larger dome islands, representing a thicker film, induce much less bending of the substrate than smaller hut islands, representing a thinner film, in direct contrast to their behavior on thick Si. We explain these observations by properly considering the island shape and strain relaxation within the island.
Type Text
Publisher American Physical Society
Journal Title Physical Review B
Volume 72
Issue 8
DOI 10.1103/PhysRevB.72.085450
citatation_issn 1098-0121
Subject Nanoscale ultrathin substrates; Strained thin films; Islands; Heteroepitaxial growth; Si substrate; Ge film
Subject LCSH Thin films; Epitaxy; Bending
Language eng
Bibliographic Citation Huang, M. H., Rugheimer, P., Lagally, M. G., & Liu, F. (2005). Bending of nanoscale ultrathin substrates by growth of strained thin films and islands. Physical Review B, 72(8), 085450.
Rights Management (c) American Physical Society
Format Medium application/pdf
Format Extent 329,896 bytes
Identifier ir-main,12159
ARK ark:/87278/s69s28kx
Setname ir_uspace
Date Created 2012-06-13
Date Modified 2021-05-06
ID 706379
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