Extensive electromechanical characterization of PZT thin films for MEMS applications by electrical and mechanical excitation signals

In this work we present a unique measurement method to estimate the effective transverse piezocoefficient e(31,f) of piezoelectric thin films which is often used in micro electromechanical systems (MEMS). This method utilizes basically a 4-point bending setup specially adapted to be used with thin film samples. It allows the application of very homogeneous well defined mechanical stresses to the device. Stress and corresponding strain distribution are verified by Finite Element simulations. Measurements are shown to demonstrate the capability and repeatability of the setup on sol-gel processed PZT thin film samples. In conjunction with additional measurement results it is possible to fully determine the electromechanical characteristics.