Ellipsometer is an optical technology that uses Ångström resolution to estimate the thickness of the base layer. It examines a sample's reflected polarized beam to see how the sample's structure impacts the beam, allowing it to deduce material attributes via discrete area analysis or mapping modes.
Ellipsometers can be used for a variety of tasks, including sample composition, film thickness measuring, film thickness mapping, determining optical constants, and determining sample crystallinity.
To examine the material, the ellipsometer uses elliptically polarized light, which consists of two out-of-phase beams. As a result, it's known as ellipsometry. This is an optical, non-invasive, and non-destructive technique for detecting polarization changes in incident beams after they have been reflected from the sample. The material qualities can then be determined by comparing this effect to mathematical models. The sample is usually thought to be made up of a few discrete, well-defined layers that are optically homogenous and isotropic.
The thickness of the sample, the complex refractive index, and the dielectric function tensor all affect polarization. The ratio of the system's amplitude component (Ψ) and phase difference (Δ) is directly measured, and then model analysis is used to deduce material attributes. As a result, the values of and are always correct, while the material properties' accuracy is dependent on the model chosen. However, because ellipsometry relies on polarization information, it is not constrained by diffraction in the measurement and can achieve Ångström resolution. This approach is appropriate for thin films in the nanometer range.
Accurion Nanofilm EP4 Imaging Ellipsometer
The imaging ellipsometer is a device that combines ellipsometry and microscopic imaging in one device. With ellipsometry's sensitivity to microstructures as fine as 1 m, it is now possible to quantify thickness and refractive index. The tiny component can simultaneously measure all structures in the optical system's field of view.
For the obtained microscopic image, the microscopic component can give ellipsometric improved contrast. In the camera's live view, small changes in refractive index or thickness can be noticed. This enables for the identification of the region of interest for ellipse measurement and the determination of thickness (0.1 nm to 10 m) and refractive index values. In one measurement, a 3D map of lateral variations in thickness and/or refractive index can be created.
It can also be used in conjunction with other technologies to observe the same area, such as AFM, QCM-D, reflectometer, and Raman.
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