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%.