Nanoscale diffusion and solid state reaction in layered structures: XRR, XRD, GIXRF, EXAFS, XSW

Research output: Chapter in Book/Report/Conference proceedingChapter

Abstract

Layered materials, such as multilayers and thin films, play a very important role in materials science and also in great variety of applications, since these structures possess interesting physical properties. As their enhanced properties are related to the layered structure, its degradation leads to the deterioration of the properties. One of the main reasons of degradation is that the atoms diffuse through the interfaces resulting in diffuse interfaces or even in complete loss of the structure. In certain cases, however, the controlled "smearing" of the interface may be beneficial. For example, in micro-or nanoelectronics, metal-semiconductor contacts are prepared by heat treating the metal/semiconductor structure (metallization) to form a thin silicide layer at the interface. Moreover, the properties of the devices may be tuned by adequate annealing, i.e. by changing their structure. These make clear that the knowledge of the structure and its change during heat treatment is very important. In this review we will show examples how synchrotron techniques can be used to reveal interesting interface phenomena on the nanoscale. Accurate knowledge of the diffusion coefficients is indispensable to understand and interpret nanoscale diffusion and solid state reaction phenomena. Although tremendous amount of data for diffusion coefficients is available in the literature, more and more measurements have been performed recently, since due to the improvement of the sample preparation and measurement techniques much more accurate experiments can be performed than earlier. Atomic scale diffusion/reaction length can be detected and evaluated with great accuracy. We will show how x-ray reflectivity (XRR) can be used to measure diffusion coefficients in compositionally or isotopically modulated multilayers. We will show how x-ray diffraction (XRD) can be used to reconstruct the interface structure or to follow silicide formation (in general solid state reaction). Moreover, we will illustrate how composition profiles and any chemical information can be gained from a combination of experimental methods of GIXRF (grazing incidence x-ray fluorescence analysis) and EXAFS (extended x-ray absorption fine structure) with XSW (x-ray standing) waves technique. Thanks to the waveguide structure, x-ray standing waves could be generated inside the layered structure by exploiting the effect of total reflection from the high Z (atomic number) waveguides, allowing extreme sensitive depth selectivity.

Original languageEnglish
Title of host publicationSynchrotron
Subtitle of host publicationDesign, Properties and Applications
PublisherNova Science Publishers, Inc.
Pages115-132
Number of pages18
ISBN (Print)9781620812020
Publication statusPublished - Oct 1 2012

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Keywords

  • Diffusion
  • Solid state reaction
  • Synchrotron techniques (XRD, XRR, GIXRF, EXAFS, XSW)

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Erdélyi, Z. (2012). Nanoscale diffusion and solid state reaction in layered structures: XRR, XRD, GIXRF, EXAFS, XSW. In Synchrotron: Design, Properties and Applications (pp. 115-132). Nova Science Publishers, Inc..