Picture of Variable Angle Spectroscopic Ellipsometer
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2nd Responsible:
Solid State Physics
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Variable angle spectroscopic ellipsometer manufactured by Woolam co.


General purpose:


Measurement of change in polarization state of light reflected of the surface of (or transmitted through) a sample. The data can be related to the complex refractive index of the material, thickness and other properties (porosity, doping, composition, etc.)

Technical specifications:

  • Components: Vertical ellipsometer system, HS190 monochromator and VB-250 control box.
  • Spectral range provided from the monochromator: 250 to 1700 nm.
  • Wavelength range: 300 nm to 1700 with the IR fiber. From 250 nm to 1700 except for a window between 1350-1400 nm with UV fiber.
  • Angle of incidence with an accuracy of 0.010°
Tool name:
Variable Angle Spectroscopic Ellipsometer
Tool ID:
Woolam co
VASE system, HS190 (monochromator), VB250 (control

Check-list for M-2000 Spectroscopic Ellipsometer Operation


This is not a manual, so do check the tool manual for further details.


Reserve your time in Å-LIMS (http://lims.eqp.angstrom.uu.se/). The tool is called Variable Angle Spectroscopic Ellipsometer (00198) there.


  • Check what type of fiber (IR or UV) is on the system. The IR fiber is the default. Contact the tool responsible if you need to change it (do not bend the fibers extensively and do not touch their ends).
  • Turn on the VB-400 control box.
  • Turn on the vacuum pump.
  • Turn on the monochromator power.
  • Turn on the lamp power.
  • Press ignition and check that light goes on.
  • Note the time.
  • Turn on the computer and the screen.


  • Start WVASE32.
  • If needed, do Window/Reset Window Layout.
  • If needed, do Window/Hardware.
  • Initialize with your name.
  • Adjust the Current Motor Settings.
  • PLEASE be careful with the calibration wafer. ALWAYS use gloves to grab the sample by the edges, and put the shiny side downwards in the box immediately after use. Lid closes counterclockwise.
  • Mount the calibration wafer. Blow any dust off using the N2 gun.
  • Align the calibration wafer using the alignment detector (use piece of paper if way off). Aim to get within ± 0.2 offset. Remember to take the detector off before proceeding with the z-alignment.
  • Let 15 min pass after turning the lamp on.
  • Do NOT do a Rough calibration. Do a Fine Calibration in both UV/Vis and IR range. Default settings are fine (10 Revs/Measurement at 21 points, Degree span 100°, AOI 70°). You may want to change the AOI to something closer to the range you have in mind, if different.
  • Unmount the calibration wafer and put it back in the box (see above).
  • If the sample is transparent, consider taping the back with Scotch magic or other light diffusive tape. Please do not leave scrap pieces of tape on the table. Use white light to check the spot position (Move/Monochromator → White light).
  • Mount the sample. Blow any dust off using the N2 gun.
  • Align the sample using the alignment detector. Aim within ± 0.2 offset. Remember to take the detector off before proceeding with the z-alignment. If the sample produces significant backside reflection, make sure to align with respect to the front side.


  • Set the measurement up. With a spectroscopic scan, the default settings are usually fine, but you may adjust the AOI depending on the pseudo-Brewster angle of your stack.
  • With the IR fiber, wavelengths from 260 nm can usually be measured.
  • With the UV fiber, wavelengths from 250 nm can usually be measured. Remember to skip the blocked band in the IR by ticking the box.
  • Name, comment and measure the sample.
  • You can expect a measurement time of about 70 min unless the specular reflectance is low in some part of the spectrum (usually in the UV).
  • Unmount the sample and switch from Vacuum to Vent.
  • To export data to a format compatible with CompleteEase: In the Experiment window, right click and use the CompleteEase Data Transfer menu.


  • Exit WVASE32.
  • Turn off the computer and screen.
  • Turn off the lamp power.
  • Turn off the monochromator.
  • Turn off the vacuum pump.
  • Turn off the control box.
  • If the UV fiber was used, switch it back to the IR fiber.


Questions, problems or comments: see contact info for tool responsible in Å-LIMS.


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