J.A. Woollam Variable Angle Spectroscopic Ellipsometer

A J.A. Woollam variable angle spectroscopic ellipsometer (VASE) was acquired in 2006. 

This instrument is used to characterize surfaces, thin films, and microstructure through the use of polarized light. Some of the material properties that can be determined are optical constants, film thicknesses, doping concentration, surface and interfacial roughness, alloy ratio, crystallinity, and optical anisotropy.



Instrument Specifications

Measurement Capabilities
  • Reflection and Transmission Ellipsometry
  • Generalized Ellipsometry (Anisotropy, Retardance, Birefringence)
  • Reflectance (R) and Transmittance (T) intensity
  • Cross-polarized R/T
  • Depolarization
  • Scatterometry
  • Mueller-matrix
Spectral Range
  • 250-1100nm (single chamber standard)
  • 240-1100nm (double chamber standard)
  • DUV extension to 193nm
  • NIR extension to 1700nm
  • XNIR extension to >2200nm
  • XXIR extension to 2500nm

System Configuration

  • Rotating Analyzer Ellipsometry (RAE) with patented AutoRetarder®. Automated wavelength selection via monochromator.

Temperature Control

  • Heating stage for variable temperature studies from 298K - 573K (RT - 300°C).

Data Acquisition Rate

  • Typical: 0.1 to 3 seconds per wavelength, depending on reflectivity of sample.
  • High Accuracy: measurements using full AutoRetarder capability require 20 seconds per wavelength.

Angle of Incidence

  • Fully Automated
  • Range: 15°-90° (standard system)
  • Accuracy: 0.01°