In-situ TEM straining experiments of Al films on polyimide using a novel FIB design for specimen preparation

Dehm, Gerhard; Legros, Marc; Heiland, Birgit

doi:10.1007/s10853-006-0087-7

Cited by 27 publications

(10 citation statements)

References 22 publications

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“…Al films deposited as single crystals on NaCl substrates were subsequently spin-coated with $10-lm-thick polyimide at Max Planck Institute (MPI-Stuttgart, Germany). A stretchable structure made of Al film on polyimide was then obtained by dissolving the salt substrate (Dehm et al, 2006).…”

Section: Materials and Methods Processing Of Metallic Filmsmentioning

confidence: 99%

In situ deformation of thin films on substrates

Legros

Cabié

Gianola

2009

Microscopy Res & Technique

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Metallic thin-film plasticity has been widely studied by using the difference between the coefficients of thermal expansion of the film and the underlying substrate to induce stress. This approach is commonly known as the wafer curvature technique, based on the Stoney equation, which has shown that thinner films have higher yield stresses. The linear increase of the film strength as a function of the reciprocal film thickness, down to a couple hundred nanometers, has been rationalized in terms of threading and interfacial dislocations. Polycrystalline films also show this kind of dependence when the grain size is larger than or comparable to the film thickness. In situ TEM performed on plan-view or cross-section specimens faithfully reproduces the stress state and the small strain levels seen by the metallic film during wafer curvature experiments and simultaneously follows the change in its microstructure. Although plan-view experiments are restricted to thinner films, cross-sectional samples where the film is reduced to a strip (or nanowire) on its substrate are a more versatile configuration. In situ thermal cycling experiments revealed that the dislocation/interface interaction could be either attractive or repulsive depending on the interfacial structure. Incoherent interfaces clearly act as dislocation sinks, resulting in a dislocation density drop during thermal cycles. In dislocation-depleted films (initially thin or annealed), grain boundaries can compensate for the absence of dislocations by either shearing the film similarly to threading dislocations or through fast diffusion processes. Conversely, dislocations are confined inside the film by image forces in the cases of epitaxial interfaces on hard substrates. To increase the amount of strain seen by a film, and to decouple the effects of stress and temperature, compliant substrates can also be used as support for the metallic film. The composite can be stretched at a given temperature using heating/cooling straining holders. Other in situ TEM methods that served to reveal scaling effects are also reviewed. Finally, an alternate method, based on a novel bending holder that can stretch metallic films on rigid substrates, is presented. Microsc. Res. Tech. 00:000-000, 2009. V

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Section: Materials and Methods Processing Of Metallic Filmsmentioning

confidence: 99%

In situ deformation of thin films on substrates

Legros

Cabié

Gianola

2009

Microscopy Res & Technique

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“…Earlier in situ studies involved conventional specimen preparation and actuation mechanisms [17][18][19] that lacked quantitative data on stress-strain and hence visualized a specimen's deformation as a function of strain only. The advent of microelectromechanical systems (MEMS) sensors and actuators opened up the possibility of truly quantitative testing in the TEM.…”

Section: Designing Mems For Nanoscale Materials Testingmentioning

confidence: 99%

“…19,[29][30][31] Thin-film properties are sensitive to synthesis and processing conditions, hence different theories exist on their deformation mechanisms. One of these is based on smaller grain sizes, which cannot accommodate statistically significant dislocations.…”

Section: Mems-based Mechanical Testingmentioning

confidence: 99%

MEMS for In Situ Testing—Handling, Actuation, Loading, and Displacement Measurements

Haque

Espinosa²,

Lee³

2010

MRS Bull.

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Mechanical testing of micro- and nanoscale materials is challenging due to the intricate nature of specimen preparation and handling and the required load and displacement resolution. In addition, in Situ testing requires the entire experimental setup to be drastically miniaturized, because conventional high-resolution microscopes or analytical tools usually have very small chambers. These challenges are increasingly being addressed using microelectromechanical systems (MEMS)-based sensors and actuators. Because of their very small size, MEMS-based experimental setups are the natural choice for materials characterization under virtually all forms of in Situ electron, optical, and probe microscopy. The unique advantage of such in Situ studies is the simultaneous acquisition of qualitative (up to near atomic visualization of microstructures and deformation mechanisms) and quantitative (load, displacement, flaw size) information of fundamental materials behavior. In this article, we provide a state-of-the-art overview of design and fabrication of MEMS-based devices for nanomechanical testing. We also provide a few case studies on thin films, nanowires, and nanotubes, as well as adhesion-friction testing with a focus on in Situ microscopy. We conclude that MEMS devices offer superior choices in handling, actuation, and force and displacement resolutions. Particularly, their tight tolerances and small footprints are difficult to match by off-the-shelf techniques.

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“…Traditional thin film nanoindentation techniques cannot be applied to freestanding films [21]. For free-standing films, thin film bulge testing [20], MEMS devices [22], and in-situ straining holders for both transmission electron microscopy (TEM) and scanning electron microscopy (SEM) [19,23] can be applied, but only straining holders allow detailed characterization of the cracking process. Though straining holders give high stability for imaging, they are limited in the extraction of mechanical data, as the load or stress is mostly unknown.…”

Section: Introductionmentioning

confidence: 99%

In-Situ Measurements of Free-Standing, Ultra-Thin Film Cracking in Bending

et al. 2015

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Metallic thin films are widely used and relied upon for various technologies. Direct measurements of fracture toughness are rare for metallic thin films and existing methods for obtaining these measurements often do not provide characterization of the cracking process for determination of crack growth mechanisms. To rectify this, we explore a new technique which utilizes doubly clamped, in-situ three-point bend testing of micro-scale and nano-scale specimens. This is done by in-situ scanning electron microscopy (SEM) and transmission electron microscopy (TEM) mechanical testing for specimens with thicknesses of 2500 nm (SEM), 500 nm (SEM) and 100 nm (TEM). For in-situ TEM, a novel notching method is employed using the converged electron beam which achieves a notch radius of approximately 5 nm. Additionally, we present supporting characterization using Electron Backscatter Diffraction (EBSD) for 2500 nm thick specimens as a demonstration of the potential of this technique for understanding local deformation. Analysis of the acquired data presents several issues that require addressing, and recommendations for future improvements are given.

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In-situ TEM straining experiments of Al films on polyimide using a novel FIB design for specimen preparation

Cited by 27 publications

References 22 publications

In situ deformation of thin films on substrates

In situ deformation of thin films on substrates

MEMS for In Situ Testing—Handling, Actuation, Loading, and Displacement Measurements

In-Situ Measurements of Free-Standing, Ultra-Thin Film Cracking in Bending

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