Multiscale experiments and models have repeatedly shown that thermal and mechanical properties of materials are a strong function of the length scale of measurement. This work uses a newly established nanomechanical Raman spectroscopy approach to analyze creep deformation of microscale Si cantilevers as a function of temperature and mechanical strain. This research reports in-situ creep properties of silicon micro-cantilevers in this temperature range under uniaxial compressive stress. The experimental setup consists of micro-scale mechanical loading platform and localized heating module. The results reveal that in the stress range of 50–150 MPa, the strain rate of the silicon cantilever increases linearly as a function of applied stress. The strain rate also increases a function of temperature increase. However, the strain rate increase slows down with increase in temperature. The strain rate of the microscale silicon cantilever (0.2–2.5 × 10-6 s-1) was comparable to literature values for bulk silicon reported in temperature range 1100–1300 °C but with only one tenth of the applied stress level. The relaxation of the near-surface atoms also contributes to the creep of the material. Analyses are also used to establish a surface stress relation in one dimensional nanostructures subjected to mechanical loading at high temperatures.
CITATION STYLE
Zhang, Y., Gan, M., & Tomar, V. (2016). Small scale thermomechanics in Si with an account of surface stress measurements. In Conference Proceedings of the Society for Experimental Mechanics Series (Vol. 7, pp. 247–250). Springer New York LLC. https://doi.org/10.1007/978-3-319-21762-8_31
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