Analysis - Ellipsometry

Ellipsometry is a model-based measurement technique that can be used to determine certain physical and optical properties of semiconductor, dielectric, and metallic materials. Measurements of variations in the polarization of light reflected from a sample's surface are compared against values calculated based on the sample's composition. The model parameters are then tweaked until excellent agreement with the measured results is achieved. Characteristic sample properties that can ultimately be extracted from the model include:

  • optical constants n and k
  • thicknesses of single- or multi-layer films
  • interface roughness
  • doping concentrations
  • crystallinity
  • alloy ratio
  • optical anisotropy

Ellipsometers available in the CEDT characterization lab

The CEDT maintains two ellipsometers that are located in the characterization lab.

These include:

  • a Philips fixed wavelength, fixed angle ellipsometer with 632.8nm HeNe source
  • a J.A. Woolam IR-VASE variable angle, spectroscopic ellipsometer suitable for measurements from 2 to 33 microns