Strain in silicon nanowire beams
(2012) Journal of Applied Physics — Vol. 112, n° 11, p. 114506 (2012)
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- Abstract
- In this work, strain in silicon free standing beams loaded in uniaxial tension is experimentally and theoretically investigated for strain values ranging from 0 to 3.6%. The fabrication method allows multiple geometries (and thus strain values) to be processed simultaneously on the same wafer while being studied independently. An excellent agreement of strain determined by two non-destructive characterization techniques, Raman spectroscopy and mechanical displacement using scanning electron microscopy (SEM) markers, is found for all the sample lengths and widths. The measured data also show good agreement with theoretical predictions of strain based upon continuum mechanical considerations, giving validity to both measurement techniques for the entire range of strain values. The dependence of Young's modulus and fracture strain on size has also been analyzed. The Young's modulus is determined using SEM and compared with that obtained by resonance-based methods. Both methods produced a Young's modulus value close to that of bulk silicon with values obtained by resonance-based methods being slightly lower. Fracture strain is analyzed in 40 sets of samples with different beam geometries, yielding values up to 3.6%. The increase in fracture strain with decreasing beam width is compared with previous reports. Finally, the role of the surface on the mechanical properties is analyzed using UV and visible lasers having different penetration depths in silicon. The observed dependence of Raman shift on laser wavelength is used to assess the thermal conductivity of deformed silicon. © 2012 American Institute of Physics.
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Urena, F., Olsen, S. H., Šiller, L., Bhaskar, U. K., Pardoen, T., & Raskin, J.-P. (2012). Strain in silicon nanowire beams. Journal of Applied Physics, 112(11), 114506. https://doi.org/10.1063/1.4765025 (Original work published 2012)