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Journal ArticleDOI

Scanning X-ray microdiffraction with submicrometer white beam for strain/stress and orientation mapping in thin films.

TL;DR: Scanning X-ray microdiffraction (microSXRD) combines the use of high-brilliance synchrotron sources with the latest achromaticX-ray focusing optics and fast large-area two-dimensional-detector technology to study thin aluminium and copper blanket films and lines following electromigration testing and/or thermal cycling experiments.
Abstract: Scanning X-ray microdiffraction (µSXRD) combines the use of high-brilliance synchrotron sources with the latest achromatic X-ray focusing optics and fast large-area two-dimensional-detector technology. Using white beams or a combination of white and monochromatic beams, this technique allows for the orientation and strain/stress mapping of polycrystalline thin films with submicrometer spatial resolution. The technique is described in detail as applied to the study of thin aluminium and copper blanket films and lines following electromigration testing and/or thermal cycling experiments. It is shown that there are significant orientation and strain/stress variations between grains and inside individual grains. A polycrystalline film when investigated at the granular (micrometer) level shows a highly mechanically inhomogeneous medium that allows insight into its mesoscopic properties. If the µSXRD data are averaged over a macroscopic range, results show good agreement with direct macroscopic texture and stress measurements.

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Citations
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Journal ArticleDOI
TL;DR: The components of the macroscopic mechanical stress tensor of a stressed thin film, coating, multilayer or the region near the surface of a bulk material can in principle be determined by X-ray diffraction as discussed by the authors.
Abstract: The components of the macroscopic mechanical stress tensor of a stressed thin film, coating, multilayer or the region near the surface of a bulk material can in principle be determined by X-ray diffraction. The various analysis methods and measurement strategies, in dependence on specimen and measurement conditions, are summarized and evaluated in this paper. First, different X-ray diffraction geometries (conventional or grazing incidence) are described. Then, the case of macroscopically elastically isotropic, untextured specimens is considered: from the simplest case of a uniaxial state of stress to the most complicated case of a triaxial state of stress. The treatment is organized according to the number of unknowns to be determined (i.e. the state of stress, principal axes known or unknown), the use of one or several values of the rotation angle φ and the tilt angle ψ of the sample, and one or multiple hkl reflections. Next, the focus is on macroscopically elastically anisotropic (e.g. textured) specimens. In this case, the use of diffraction (X-ray) elastic constants is not possible. Instead, diffraction (X-ray) stress factors have to be used. On the basis of examples, it is demonstrated that successful diffraction stress analysis is only possible if an appropriate grain-interaction model is applied.

529 citations


Cites methods from "Scanning X-ray microdiffraction wit..."

  • ...For this reason, methods for the analysis of local stresses down to the submicrometre scale by microdiffraction employing synchrotron radiation, a rapidly developing field of research (see, for example, Tamura et al., 2003, and references therein), have been excluded....

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Journal ArticleDOI
TL;DR: A new facility for microdiffraction strain measurements and microfluorescence mapping has been built at the advanced light source of the Lawrence Berkeley National Laboratory and allows a variety of experiments, which have in common the need of spatial resolution.
Abstract: A new facility for microdiffraction strain measurements and microfluorescence mapping has been built on beamline 12.3.2 at the advanced light source of the Lawrence Berkeley National Laboratory. This beamline benefits from the hard x-radiation generated by a 6 T superconducting bending magnet (superbend). This provides a hard x-ray spectrum from 5 to 22 keV and a flux within a 1 microm spot of approximately 5x10(9) photons/s (0.1% bandwidth at 8 keV). The radiation is relayed from the superbend source to a focus in the experimental hutch by a toroidal mirror. The focus spot is tailored by two pairs of adjustable slits, which serve as secondary source point. Inside the lead hutch, a pair of Kirkpatrick-Baez (KB) mirrors placed in a vacuum tank refocuses the secondary slit source onto the sample position. A new KB-bending mechanism with active temperature stabilization allows for more reproducible and stable mirror bending and thus mirror focusing. Focus spots around 1 microm are routinely achieved and allow a variety of experiments, which have in common the need of spatial resolution. The effective spatial resolution (approximately 0.2 microm) is limited by a convolution of beam size, scan-stage resolution, and stage stability. A four-bounce monochromator consisting of two channel-cut Si(111) crystals placed between the secondary source and KB-mirrors allows for easy changes between white-beam and monochromatic experiments while maintaining a fixed beam position. High resolution stage scans are performed while recording a fluorescence emission signal or an x-ray diffraction signal coming from either a monochromatic or a white focused beam. The former allows for elemental mapping, whereas the latter is used to produce two-dimensional maps of crystal-phases, -orientation, -texture, and -strain/stress. Typically achieved strain resolution is in the order of 5x10(-5) strain units. Accurate sample positioning in the x-ray focus spot is achieved with a commercial laser-triangulation unit. A Si-drift detector serves as a high-energy-resolution (approximately 150 eV full width at half maximum) fluorescence detector. Fluorescence scans can be collected in continuous scan mode with up to 300 pixels/s scan speed. A charge coupled device area detector is utilized as diffraction detector. Diffraction can be performed in reflecting or transmitting geometry. Diffraction data are processed using XMAS, an in-house written software package for Laue and monochromatic microdiffraction analysis.

172 citations

Journal ArticleDOI
TL;DR: Using synchrotron X-ray microdiffraction, state-of-charge profiles in-plane and normal to the current collector were measured as mentioned in this paper, showing that the portion of a prismatic cell electrode closest to the collector tab had the highest state of charge due to electronic resistance in the composite electrode and supporting foil.
Abstract: We describe a method for direct determination and visualization of the distribution of charge in a composite electrode. Using synchrotron X-ray microdiffraction, state-of-charge profiles in-plane and normal to the current collector were measured. In electrodes charged at high rate, the signatures of nonuniform current distribution were evident. The portion of a prismatic cell electrode closest to the current collector tab had the highest state of charge due to electronic resistance in the composite electrode and supporting foil. In a coin cell electrode, the active material at the electrode surface was more fully charged than that close to the current collector because the limiting factor in this case is ion conduction in the electrolyte contained within the porous electrode.

154 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used synchrotron X-ray microdiffraction with fracture mechanics techniques to directly measure in situ three-dimensional strains, phases and crystallographic alignment ahead of a growing fatigue crack (100 cycles in situ ) in superelastic Nitinol.

149 citations

08 Jul 2010
TL;DR: Using synchrotron X-ray microdiffraction, state-of-charge profiles in-plane and normal to the current collector were measured as discussed by the authors, showing that the portion of a prismatic cell electrode closest to the collector tab had the highest state of charge due to electronic resistance in the composite electrode and supporting foil.
Abstract: We describe a method for direct determination and visualization of the distribution of charge in a composite electrode. Using synchrotron X-ray microdiffraction, state-of-charge profiles in-plane and normal to the current collector were measured. In electrodes charged at high rate, the signatures of nonuniform current distribution were evident. The portion of a prismatic cell electrode closest to the current collector tab had the highest state of charge due to electronic resistance in the composite electrode and supporting foil. In a coin cell electrode, the active material at the electrode surface was more fully charged than that close to the current collector because the limiting factor in this case is ion conduction in the electrolyte contained within the porous electrode.

136 citations

References
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Journal ArticleDOI
TL;DR: Several conceivable methods for the formation of optical images by x-rays are considered, and a method employing concave mirrors is adopted as the most promising.
Abstract: Several conceivable methods for the formation of optical images by x-rays are considered, and a method employing concave mirrors is adopted as the most promising. A concave spherical mirror receiving radiation at grazing incidence (a necessary arrangement with x-rays) images a point into a line in accordance with a focal length f=Ri/2 where R is the radius of curvature and i the grazing angle. The image is subject to an aberration such that a ray reflected at the periphery of the mirror misses the focal point of central rays by a distance given approximately by S=1.5Mr2/R, where M is the magnification of the image and r is the radius of the mirror face. The theoretically possible resolving power is such as to resolve point objects separated by about 70A, a limit which is independent of the wave-length used. Point images of points and therefore extended images of extended objects may be produced by causing the radiation to reflect from two concave mirrors in series. Sample results are presented.

1,149 citations


"Scanning X-ray microdiffraction wit..." refers background in this paper

  • ...However, ultra-smooth mirrors in a Kirkpatrick±Baez (KB) orthogonal con®guration (Kirkpatrick & Baez, 1948) are the only optics to combine achromaticity, high ef®ciency and good focus....

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Journal ArticleDOI
01 Nov 1996-Nature
TL;DR: In this article, a simple procedure for fabricating refractive lenses that are effective for focusing of X-rays in the energy range 5-40 keV is described, and the problem associated with absorption is minimized by fabricating the lenses from low-atomic-weight materials.
Abstract: THE development of techniques for focusing X-rays has occupied physicists for more than a century. Refractive lenses, which are used extensively in visible-light optics, are generally considered inappropriate for focusing X-rays, because refraction effects are extremely small and absorption is strong. This has lead to the development of alternative approaches1,2 based on bent crystals and X-ray mirrors, Fresnel and Bragg–Fresnel zone plates, and capillary optics (Kumakhov lenses). Here we describe a simple procedure for fabricating refractive lenses that are effective for focusing of X-rays in the energy range 5–40 keV. The problems associated with absorption are minimized by fabricating the lenses from low-atomic-weight materials. Refraction of X-rays by one such lens is still extremely small, but a compound lens (consisting of tens or hundreds of individual lenses arranged in a linear array) can readily focus X-rays in one or two dimensions. We have fabricated a compound lens by drilling 30 closely spaced holes (each having a radius of 0.3 mm) in an aluminium block, and we demonstrate its effectiveness by focusing a 14-keV X-ray beam to a spot size of 8 μm.

973 citations


"Scanning X-ray microdiffraction wit..." refers background in this paper

  • ...…optics have been developed for X-rays during the past decade, including Fresnel zone plates (Lai et al., 1992), refractive compounds lenses (Snigirev et al., 1996), capillaries (EngstroÈ m et al., 1991; Thiel et al., 1992; Bilderback et al., 1994), waveguides (Spiller & SegmuÈ ller, 1974;…...

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Journal ArticleDOI
TL;DR: In this article, the authors studied the stresses in aluminum thin films on TiN by transmission x-ray topography and found that the stresses are more compressive in the anode regions.
Abstract: Stresses in aluminum thin films on TiN were studied in situ by transmission x‐ray topography. Stress gradients were seen to build up in thin aluminum films during passage of electrical currents. The stresses are more compressive in the anode regions. These stress gradients seem to be a concomitant of the backflow responsible for the reported threshold in electromigration, and can probably be correlated quantitatively with it.

478 citations


"Scanning X-ray microdiffraction wit..." refers background in this paper

  • ...This phenomenon is known as electromigration and generates high stress gradients in the wires (Blech & Herring, 1976)....

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Journal ArticleDOI
23 Mar 2001-Science
TL;DR: A universal method for providing data on the underlying structural dynamics at the grain and subgrain level based on diffraction with focused hard x-rays is presented.
Abstract: Texture evolution governs many of the physical, chemical, and mechanical properties of polycrystalline materials, but texture models have only been tested on the macroscopic level, which makes it hard to distinguish between approaches that are conceptually very different. Here, we present a universal method for providing data on the underlying structural dynamics at the grain and subgrain level. The method is based on diffraction with focused hard x-rays. First results relate to the tensile deformation of pure aluminum. Experimental grain rotations are inconsistent with the classical Taylor and Sachs models.

348 citations


"Scanning X-ray microdiffraction wit..." refers background in this paper

  • ...The application of monochromatic mSXRD to studies of deformation in bulk polycrystalline materials has been recently demonstrated with a three-dimensional X-ray microscope (Margulies et al., 2001)....

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Journal ArticleDOI
TL;DR: For wide polycrystalline lines, the dominant diffusion mechanism is a mixture of grain boundary and surface diffusion, while in narrow lines (< 1 μm) the dominant mechanism is surface transport as mentioned in this paper.
Abstract: Electromigration in 0.15–10 μm wide and 0.3 μm thick Cu lines deposited by physical vapor deposition has been investigated using both resistance and edge displacement techniques in the sample temperature range 255–405 °C. For wide polycrystalline lines (>1 μm), the dominant diffusion mechanism is a mixture of grain boundary and surface diffusion, while in narrow lines (<1 μm) the dominant mechanism is surface transport. The activation energy for grain-boundary transport is approximately 0.2 eV higher than that of surface transport.

310 citations


"Scanning X-ray microdiffraction wit..." refers background in this paper

  • ...Surface diffusion at the interface between Cu and the passivation layer is the dominant diffusion mechanism in Cu interconnects (Hu et al., 1999)....

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