Precise determination of d_(33) and d_(31) from piezoelectric deflection measurements and 2D FEM simulations applied to Sc_xAl_(1-x)N

摘要

The reliable characterization of piezoelectric thin film properties is important for a tailored integration into micro-electromechanical systems (MEMS). In this work a method for the determination of d_(33) and d_(31) of piezoelectric thin films is presented by comparing Laser Doppler Vibrometry (LDV) displacement curves to finite element simulations (FEM) and applied to AlN and Sc_xAl_(1-x)N (x = 27%). A rectangular 2-port electrode design for 2D FEM modelling enables the evaluation of d_(33) and d_(31) by a full implementation into a MatLab based fit function. This allows also to account for the substrate-support adhesive bond strength in the FEM evaluation process. Doing so, insufficient bond strength can be compensated.