In-SEM Raman Spectroscopy

The unique design of the Allalin column enables direct light injection, making it ideal for performing high-resolution Raman spectroscopy on the sample.

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The Allalin column’s design enables in-situ Raman spectroscopy by analyzing the spectroscopic properties of the reflected beam using specialized filters and gratings. This approach provides insights that complement cathodoluminescence spectroscopy, allowing correlative measurements on the same sample without the need for repositioning. This setup unlocks the full range of Raman applications, including:

Strain Measurement in crystalline materials
Trace Element Detection for geological analysis
Compositional Mapping in polymers and polymer alloys
Phase Identification in crystalline materials

Left: Mean spectrum of the Raman map. The additional Raman band with two maxima at 1340 and 1565 cm-1 are attributed to amorphous carbon on the sample [1]. Right: Analysis of the Si-LO peak from the hyperspectral map. Amplitude changes, shifts and broadening are attributed to patterning of the sample. The principal reason for acquisition of such maps is to assess the laser spot size / resolution of the system.

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In-SEM Raman spectroscopy is currently implemented using a 532 nm laser, though other wavelengths are available upon request. Mapping is made possible by using a specially developed stage-scanning algorithm that takes advantage of the nm-precise piezo technology featured in the Allalin stage. Precise laser power and polarization control is also featured, together with functions to automate power and polarization series.

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[1] Parker,J. H., D. W. Feldman, and M. Ashkin.“Raman Scattering by Silicon and Germanium.” PhysicalReview 155, no. 3 (March 15, 1967): 712–14. https://doi.org/10.1103/PhysRev.155.712