A simple technique to determine the anisotropy of Young's modulus of single crystal silicon using coupled micro-cantilevers

This paper reports on a simple technique to measure the anisotropy of the Young's modulus of single crystal silicon using a coupled cantilever structure fabricated in the silicon. We demonstrate that it is possible to determine the Young's modulus of five silicon micro-cantilevers, whose orientations range from 30γ to 55γ to the wafer flat, by measuring the resonance frequencies of just one single cantilever of the coupled structure in a “perturbed” and “unperturbed” state. In this work the perturbation of the coupled system was achieved by shortening one of the cantilevers using focused ion beam milling. The resulting Young's modulus values from this experiment agree very well with the theoretical values with a difference of less than 2.5%.