Mueller Matrix Ellipsometry –  A Universal Optical Characterization Technique

July 14th 1:00 PM CDT

Mueller matrix ellipsometry is one of the hottest topics in the ellipsometry field. Just like “standard ellipsometry”, this non-destructive, optical characterization technique measures the change of polarization of light upon reflection from or transmission through a sample. However, Mueller matrix ellipsometry is not limited to measuring isotropic samples where film thickness and optical constants are the primary interest. On the contrary, the Mueller matrix contains all essential optical information, from intensity propagation, over cross-polarization due to linear and circular birefringence (LB and CB), linear and circular dichroism (LD and CD), retardance, to depolarization. Essentially, any optical effect possible will be described by a Mueller matrix. By measuring the Mueller matrix, we can characterize the most advanced applications. Some examples include arbitrarily anisotropic, crystalline substrates and films, birefringence in stretched polymer foils as found in roll-to-roll applications, polarization filters in AR/VR devices or cameras, entire liquid crystal cells, oriented nanostructures, bio and metamaterials, or periodic 3d structured surfaces in semiconductor metrology.

In this webinar, the basic concept of the Mueller matrix and measurement approaches using any J.A. Woollam ellipsometer will be introduced. We identified a few representative cases to demonstrate extraction of the desired material and device properties from the raw data.

Who Should Attend?

This webinar is designed for engineers and scientists who either have an interest or need to learn about the basic principles of Mueller matrix ellipsometry. Industrial as well as research related topics will be covered. Prior knowledge of standard ellipsometry will help to relate to more advanced concepts but is not a requirement.

Will questions be answered:

Several J.A. Woollam applications engineers will be available during the seminar to answer your most pressing questions about the technique and its limitations in an interactive Q&A section. A few selected questions will be answered in detail by the presenters at the end of the webinar.

Presenters

Nina Hong. Ph.D.

Stefan Schöche, Ph.D.

Infrared Ellipsometry – Bulk and Thin Film Characterization Beyond Standard FTIR Spectroscopy

August 4th 1:00 PM CDT

For more than 23 years the J. A. Woollam IR-VASE®, FTIR-based ellipsometer (covering 1.7 to 30 µm wavelengths) has been used to study mid- and far-IR optical coatings and devices, semiconductors, photovoltaics, surface chemistry, and other applications. In contrast to standard FTIR techniques based on measuring absolute intensities, infrared spectroscopic ellipsometry (IR-SE) is a self-referencing technique that measures the change of polarization expressed as amplitude ratio tan(Ψ) and phase difference Δ between the p- and s-polarization components of a reflected or transmitted light beam. As a result, the measurement is highly accurate, precise, and repeatable. Furthermore, no reference sample is required, there is little sensitivity to fluctuations in ambient CO2 and water vapor levels or source intensity, and only a portion of the light beam needs to be collected to obtain accurate data. Model-based data analysis yields quantitative values for thicknesses as well as the refractive index and extinction coefficient, and dielectric function. For thin films on a substrate, measurement of the phase difference Δ greatly improves sensitivity for small layer thickness, often in the sub-nm range. The longer wavelengths of IR-SE (compared to NIR-Vis-UV ellipsometry) also allow measurement of thicker films up to several tens of microns. Physical sample properties such as phonon and other vibrational absorptions, free carrier density profiles, anisotropy, and gradients in the optical properties can be determined for bulk materials and thin films. Access to the depolarization of the light beam after interaction with the sample allows characterization of the film thickness uniformity over the measurement spot from a single measurement.

After a brief introduction of IR-SE and the IR-VASE® instrument, we will show examples for several applications such as IR-optical coatings and substrates, doped and undoped semiconductor substrates and coatings, polymer films, and anisotropic materials.

Who Should Attend?

This webinar is designed for engineers and scientists who either have an interest or need to learn about the Infrared ellipsometry. Industrial as well as research related topics will be covered. Prior knowledge of standard ellipsometry will help to relate to more advanced concepts but is not a requirement.

Presenters

Tom Tiwald, Ph.D.

Ron Synowicki