Auto-nulling Spectroscopic Imaging Ellipsometer

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Imaging Ellipsometry

ellipsometerEllipsometry is an optical non destructive technique allowing the accurate characterization of thin films, surface and interface. It is mainly used to determine thin film thickness (from 1Å to 2µm) and optical constants (n,k). The Ellipsometer makes use of the fact that the polarization state of light may change when the light beam is reflected from a surface. If the surface is covered by a thin film (or a stack of films), the entire optical system of film & substrate, influences the change in polarization. The ellipsometry measures two parameters, ψ and Δ, defined as the ratio of relative amplitude and phase difference for p- and s-polarized light before and after reflecting on sample surfaces1-2. The optical and geometrical properties of thin film layers are analyzed using model fitting procedure with these measured ellipsometric parameters. It is therefore possible to deduce information about the film properties, especially the film thickness.


  • Moving range of x/y/z stage: 100mm (x/y) 30mm (z)
  • Repeatability: 1 µm
  • Sample imaging area: 25x40 mm²
  • Maximum lateral resolution: 1 µm
  • Laser used: 658nm
objective area resolution lim. angle
10x 0.44 mm 2 µm 68 deg.
20x 0.22 mm 1 µm 60 deg.

Measuring modes

  • ellipsometer_graph_1Thickness measurement (measurement using one angle and one wavelength)
  • AOI-Variation (measurement with multiple angles using one wavelength)
  • Lambda Variation (measurement with multiple wavelengths using one angle)
  • Lambda-AOI-Variation (measurement using multiple angles and multiple wavelengths)
  • Kinetic (measurement over time [one angle, one wavelength])
  • Mapping (profiling thickness or n of the entire field of view, not only an average of the Region of interest)


  • ellipsometer_graph_2It combines spatial resolution of optical microscopy with thin-film measurement capabilities of ellipsometry.
  • Delta- and thickness-maps are unique features of the EP3View software that can be evaluated to obtain one unique thickness map of a thin film.
  • It can identify thickness variations in vertical resolution (<1 nm) in real time, while the sample can be moved with an automatic translation stage.
  • The Imaging Ellipsometer EP3 identifies steps in monolayers much faster and with less effort than an SPM.


  • Material Science
  • Semiconductor Physics
  • Surface Chemistry
  • Microelectronics
  • Biophysics
  • Biology

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