UVSE vs visible spectroscopic ellipsometer

[lcr2139]

How is the UV spectroscopic ellipsometer better than a visible spectroscopic ellipsometer?

A spectroscopic ellipsometer measures thin film thicknesses and indices of refraction by measuring phase difference (delta) and amplitude change (psi). It is plotted on a reflectance vs. wavelength graph, which is better than a single wavelength ellipsometer because the single wavelength ellipsometer only measures at one wavelength and can only measure the thickness of a single transparent layer and the refractive index of that wavelength, and a multiwavelength ellipsometer (spectroscopic ellipsometer) is more accurate because it measures at a spectrum of wavelengths and can be used for multilayer stacks and thin films.

I believe that the UV spectroscopic ellipsometer is more accurate than the visible spectroscopic ellipsometer because of the properties of the material under UV light. Is this true? Why?

 

[AndyW]

Yes, it is true that the UV spectroscopic ellipsometer is more accurate than the visible spectroscopic ellipsometer. This is because UV light has a shorter wavelength compared to visible light, which allows it to interact more strongly with materials. This strong interaction allows for more precise and sensitive measurements of the material's properties, such as thickness and refractive index.

Moreover, UV light is able to penetrate deeper into the material, providing more information about the internal structure and properties of thin films. This is especially important for complex multilayer structures, where the layers may have different properties and thicknesses. By using UV light, the spectroscopic ellipsometer can accurately measure the properties of each layer, resulting in a more comprehensive and accurate analysis.

Additionally, UV light is also less affected by surface roughness and contamination, which can interfere with the measurements of the visible spectroscopic ellipsometer. This further improves the accuracy of the UV spectroscopic ellipsometer.

In summary, the shorter wavelength and stronger interaction of UV light make the UV spectroscopic ellipsometer a more accurate tool for measuring thin film properties compared to the visible spectroscopic ellipsometer.