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A Ellipsometry- why is UV better than Visible light?

  1. Jun 29, 2017 #1
    Hello,

    I was wondering why UV ellipsometry is better than visible ellipsometry?
     
  2. jcsd
  3. Jun 29, 2017 #2

    Andy Resnick

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    Better for what?
     
  4. Jun 30, 2017 #3
    I meant, for certain materials, it is better to use UV light source to measure thin film thickness, and sometimes it is better to use a visible or NIR light source. Can someone please give me a couple of examples of materials that are determined using UV, VIS, and NIR? Why is it good to have the whole UV-VIS-NIR spectrum in an ellipsometer?
     
  5. Aug 28, 2017 #4
    If you only want to measure the thickness of a film, I believe that a single color i.e. laser is good enough as long as the medium has normal dispersion at that wavelength (negligible absorption). But, if you have access to a broader spectrum you can do spectroscopic ellipsometry, which allows one to more fully characterize a sample. For example, you can measure an absorption spectrum in conjuction with ellipsometry, etc. See this article https://en.wikipedia.org/wiki/Ellipsometry

    The subection on single-wavelength vs spectroscopic ellipsometry directly addresses your question.
     
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