Spectral Ellipsometry (SE)

Light waves can oscillate in different directions. A polarized light oscillates in only one direction. Non Polarized light oscillates in many directions. The process of transforming unpolarized light into polarized light is known as polarization (Figure 1). In Spectral ellipsometry, polarized light is shone upon a sample to measure its properties.

Electromagnetic radiation is emitted by a light source and linearly polarized by a polarizer. The light falls onto the sample. After reflection, the radiation passes through a second polarizer, which is called an analyzer and falls into the detector (Figure 2).

When light interacts with a thin film, its polarization changes. The change in polarization depends on the thickness and other properties of the material. Therefore, the properties of materials can be determined by measuring the change in polarization of light. The polarization change is quantified by the amplitude ratio, Ψ, and the phase difference, Δ.

The sample surface should be smooth and flat. The rear of the transparent sample should be rough. The thickness should be between 70 nm and 1 um. The area to be analyzed should be at least 1 x 1.5 mm.

The sample surface should be smooth and flat. The rear of the transparent sample should be rough. The thickness should be between 70 nm and 1 um. The area to