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ENS Cachan - Institut d'Alembert

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Spectroscopic ellipsometer

The photonic materials and components characterization platform of d'Alembert Institute includes a spectroscopic ellipsometer which can be used to measure simultaneously the thickness and complex indices (including refractive index and optical attenuation) of an organic or inorganic thin film, deposited on silicon or other semiconductor substrates.
This optical characterization of material thin films is mandatory to the design and realization of integrated photonic devices.


The spectroscopic ellipsometer can achieve continuous measurements in the spectral region ranging from the UV (210 nm) to the NIR (2000 nm). This instrument is equipped with two different photodetectors and a monochromator using a double grating to cover the operational spectral region. The spectral resolution of measurements is adjusted by the monochromator resolution. The ellipsometer is entirely controlled by a computer for different methods of measurement. The typical thickness of thin film samples ranges from hundreds of nanometers to about 2 micrometers. An estimation of the sample thickness is recommended but not mandatory before measuring its complex indices. Otherwise we can carry out sample thickness measurements using the clean room profilometer. The interpretation of measurement results is realized by fitting the ellipsometric responses using well-known physical models of thin films index dispersion. A preliminary knowledge of the semiconductor substrate complex index is required to obtain a precise interpretation of measurement results for the thin films deposited onto this substrate. The ellipsometer is equipped with an UV-filter to eliminate UV radiations below 440 nm in order to be suitable for the characterization of organic thin films which are sensitive to UV irradiation.


Contact :


Chi Thanh Nguyen
Tél.: 01 47 40 55 57

Equipments list :

 
Ellipsomètre SOPRA GES-5

Localisation :

LPQM - Salle 114 b - Bât. d'Alembert