Compliant substrates: A comparative study of the relaxation mechanisms of strained films bonded to high and low viscosity oxides

Hobart, Karl D.; Kub, Fritz J.; Fatemi, M.; Twigg, M. E.; Thompson, Phillip E.; Kuan, T. S.; Inoki, C. K.

doi:10.1007/s11664-000-0177-2

Cited by 87 publications

(38 citation statements)

References 12 publications

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“…Nevertheless, the viscoelastic evolution represents one physical process to form wrinkle patterns in experiments (e.g., Hobart et al, 2000;Yoo and Lee, 2003;Peterson et al, 2006), where the observed wrinkle patterns may also be trapped in a state of local energy minimum. It is suspected that there may exist many local minima in the energy landscape, and the observed wrinkle pattern may depend on the loading history (Biot, 1957).…”

Section: Nonlinear Analysis Of Equilibrium Statesmentioning

confidence: 99%

“…Complex wrinkle patterns have been observed in various thin-film systems with integrated hard and soft materials (e.g., Tolpygo and Clarke, 1998;Bowden et al, 1998;Hobart et al, 2000;Volynskii et al, 2000;Yoo and Lee, 2003). For many applications of the integrated material structures, wrinkling is undesirable as it may lead to failure by delamination or fracture (e.g., Suo, 1995;Martin et al, 2000;Mumm et al, 2001;Yin et al, 2003;Peterson, 2006).…”

Section: Introductionmentioning

confidence: 99%

“…The symmetry can be broken either by invoking an anisotropic biaxial stress or in a layered material system with anisotropic mechanical properties. For example, Hobart et al (2000) observed wrinkling of single-crystal silicon-germanium (SiGe) alloy films on a glass layer annealed at an elevated temperature, where the SiGe is a cubic crystal with anisotropic elastic properties. More detailed experiments (Peterson, 2006;Peterson et al, 2006) showed that the SiGe film preferentially wrinkles in two orthogonal directions, aligned with the <100> axes of the cubic crystal.…”

Section: Introductionmentioning

confidence: 99%

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Wrinkle patterns of anisotropic crystal films on viscoelastic substrates

Huang

2008

Journal of the Mechanics and Physics of Solids

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This paper presents a nonlinear mathematical model for evolution of wrinkle patterns of an anisotropic crystal film on a viscoelastic substrate layer. The underlying mechanism of wrinkling has been generally understood as a stress-driven instability. Previously, theoretical studies on wrinkling have assumed isotropic elastic properties for the film. Motivated by recent experimental observations of ordered wrinkle patterns in single-crystal thin films, this paper develops a theoretical model coupling anisotropic elastic deformation of a crystal film with viscoelastic deformation of a thin substrate layer. A linear perturbation analysis is performed to predict onset of the wrinkling instability and the initial evolution kinetics; an energy minimization method is adopted to analyze wrinkle patterns at the equilibrium states. For a cubic crystal film under an equi-biaxial compression, orthogonally ordered wrinkle patterns are predicted at both the initial stage and the equilibrium state. This is confirmed by numerical simulations of evolving wrinkle patterns. By varying the residual stresses in the film, numerical simulations show that a variety of wrinkle patterns (e.g., orthogonal, parallel, zigzag, and checkerboard patterns) emerge as a result of the competition between the material anisotropy and the stress anisotropy.

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Section: Nonlinear Analysis Of Equilibrium Statesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Wrinkle patterns of anisotropic crystal films on viscoelastic substrates

Huang

2008

Journal of the Mechanics and Physics of Solids

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“…Recently, Hobart and co-workers have studied the relaxation of SiGe islands transferred to a viscous borophosphorosilicate glass (BPSG) layer [ 25] . Following this initial work, we and others have studied this process with a combination of experiment and theory [26~33].…”

Section: Introductionmentioning

confidence: 99%

“…This article integrates these studies, provides some evidences for wrinkle-induced fracture, and demonstrates an improved method to fabricate large, zero-defect, and strain-relaxed SiGe islands. Figure 1 illustrates the fabrication process [25] . Grow an epitaxial SiGe film on a Si host wafer.…”

Section: Introductionmentioning

confidence: 99%

Mechanics of relaxing SiGe islands on a viscous glass

et al. 2002

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A process has been developed recently to fabricate a structure comprising, from top to bottom, a SiGe thin film, a glass layer, and a Si wafer. The SiGe film is a perfect crystal, and is under biaxial compression. The SiGe film is patterned into islands. On annealing, the glass flows and the islands relax. The resulting strain-free islands are used as substrates, to grow epitaxial optoelectronic devices. This article describes a series of studies on the anneMing process, combining experiment and theory. A small island relaxes by expansion, starting at the edges and diffusing to the center. A large island wrinkles before the expansion reaches the center. After some time, the wrinkles either disappear, or cause the island to fracture. We model the island as an elastic plate, and the glass layer as a viscous liquid. The strains in the islands are measured by X-ray diffraction and Raman spectroscopy, and the wrinkle amplitudes by atomic force microscope. The data are compared with the theoretical predictions. We determine the conditions under which the islands relax by expansion without significant wrinkling, and demonstrate that a cap layer suppresses wrinkles, relaxing a large island crack-free.

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Wafer‐Scale Strain Engineering of Ultrathin Semiconductor Crystalline Layers

et al. 2011

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The fabrication of a wafer-scale dislocation-free, fully relaxed single crystalline template for epitaxial growth is demonstrated. Transferring biaxially-strained Inx Ga1-x As ultrathin films from InP substrates to a handle support results in full strain relaxation and the Inx Ga1-x As unit cell assumes its bulk value. Our realization demonstrates the ability to control the lattice parameter and energy band structure of single layer crystalline compound semiconductors in an unprecedented way.

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Compliant substrates: A comparative study of the relaxation mechanisms of strained films bonded to high and low viscosity oxides

Cited by 87 publications

References 12 publications

Wrinkle patterns of anisotropic crystal films on viscoelastic substrates

Wrinkle patterns of anisotropic crystal films on viscoelastic substrates

Mechanics of relaxing SiGe islands on a viscous glass

Wafer‐Scale Strain Engineering of Ultrathin Semiconductor Crystalline Layers

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