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  • Fast ellipsometric measurements based on a single crystal photo-elastic modulator
    Petkovšek, Rok, fizik ...
    For quality control in high volume manufacturing of thin layers and for tracking of physical and chemical processes, ellipsometry is a common measurement technology. For such kinds of applications we ... present a novel approach of fast ellipsometric measurements. Instead of a conventional setup that uses a standard photo-elastic modulator, we use a 92 kHy Single Crystal Photo-Elastic Modulator (SCPEM), which is a LiTaO3 crystal with a size of 28 *9 * 4 mm. This small, simple, and cost-effective solution also offers the advantage of direct control of the retardation via the current amplitude, which is important for repeatability of the measurements. Instead of a Lock-InAmplifier, an automated digital processing based on a fast analog to digital converter controlled by a highly flexible Field Programmable Gate Array is used. This and the extremely compact and efficient polarization modulation allow fast ellipsometric testing where the upper limit of measurement rates is mainly limited by the desired accuracy and repeatability of the measurements. The standard deviation that is related to the repeatability +/-0.002° for dielectric layers can be easily reached.
    Source: Optics express [Elektronski vir]. - ISSN 1094-4087 (Vol. 18, no. 20, 2010, str. 21410-21418)
    Type of material - article, component part
    Publish date - 2010
    Language - english
    COBISS.SI-ID - 11554331
    DOI

source: Optics express [Elektronski vir]. - ISSN 1094-4087 (Vol. 18, no. 20, 2010, str. 21410-21418)

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