Ellipsometry
Ellipsometry is a very sensitive measurement technique for characterising thin films, surfaces and material microstructure using reflected polarised light.
A beam of polarised light is directed onto a sample, and the reflected beam is analysed to determine its state of polarisation. The net result is that two values are measured - the reflection coefficient and the phase difference. Depending on the detail of the experiment, these can be measured as a function of incident angle and incident wavelength.
These parameters are very sensitive to the properties of any material either on or near the surface of the sample. As such the technique is particularly useful for studying thin films and surface properties.
Analysis is often done by modelling the sample and comparing the theoretical result to the empirical data.
Facilities Include:
a Beaglehole spectroscopic ellipsometer
Applications Include:
- Semiconductor - lithography, ultra-thin gates
- Data Storage - DLC for read/write heads for hard disks
- Chemical & Biological - protein adsorption, self assembled monolayers, L-B films