ELLIPSOMETRY Meaning and
Definition
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Ellipsometry is a non-destructive optical technique used for measuring the optical properties and thickness of thin films and multi-layered structures. It is based on the principle of measuring changes in the polarization state of light after interaction with the sample surface.
In ellipsometry, a beam of polarized light is incident onto the sample, and the reflected light is analyzed to determine changes in the phase and amplitude of the polarization. By measuring these changes, information about the complex refractive index, thickness, and roughness of thin films can be obtained.
The ellipsometer measures two important parameters: the change in phase difference between the p-polarized and s-polarized light, known as the ellipsometric angle, and the ratio of the reflected light's intensity for different polarizations, known as the amplitude ratio. These measurements are used to calculate the ellipsometric parameters, which are then compared to theoretical models or databases to determine the sample characteristics.
Ellipsometry finds applications in various fields, including materials science, semiconductor industry, surface chemistry, and bio-sensing. It provides valuable information about film thickness, optical constants, composition, and other properties of thin films, making it a powerful tool for characterization and quality control.
Overall, ellipsometry is a precise and versatile technique that plays a crucial role in understanding and analyzing the optical properties of thin films, enabling advancements in various technological domains.
Etymology of ELLIPSOMETRY
The word "ellipsometry" is derived from the combination of two Greek words: "ellipse" and "metry".
- "Ellipse" (ἔλλειψις) refers to a geometric shape that resembles an elongated or flattened circle, similar to an oval. It is derived from the Greek words "en" meaning "in" and "elleipein" meaning "to fall short" or "to leave out".
- "Metry" (μέτρηση) comes from the Greek word "metron" meaning "measure" or "measurement".
Therefore, "ellipsometry" refers to the measurement technique that relies on the analysis of light reflected or transmitted from an ellipsoidal surface or interface, typically to determine physical properties or characteristics of materials.
