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WEB Micro reflectance anisotropy spectroscopy as a new tool for stress and crystal orientation mapping in thin films

Wednesday (01.01.2020)
05:00 - 05:15
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Microstructure strongly influences the mechanical properties of thin films. Consequently, the characterization of mechanical behavior at small length scales is fundamental. In particular, stress mapping is of great interest since it allows the study of fracture mechanics, e.g. visualizing the stress distribution around a crack tip. Conventional lab scale stress mapping techniques are based on electron microscopy (EM) and Raman spectroscopy (RS). Common drawbacks are the required high vacuum for EM and the need of Raman active materials for RS, hindering the range of materials that can be analyzed. Here, we present an advanced reflectance anisotropy spectroscopy (RAS) microscope based on a super continuum laser source as a non-destructive stress mapping technique for a wide range of materials. Our microscope enables insight into the electronic band structure, phase and crystal orientation. We demonstrate strain mapping in sputtered thin films on flexible substrates and outline the potential of the technique for mapping grain orientation using polycrystalline copper. The simultaneous stress and grain orientation mapping will enable future studies on the fracture mechanics of thin films and novel materials with different microstructure and environmental conditions.

Joan Sendra
ETH Zurich
Additional Authors:
  • Micha Calvo
    ETH Zürich
  • Marco Volpi
    ETH Zürich
  • Dr. Henning Galinski
    ETH Zürich
  • Prof. Ralph Spolenak
    ETH Zürich