Circular Patterned Test Structures for Precise Determination of Piezoelectric Thin Film Constants: Application to ScxAl1-xN

Piezoelectric scandium aluminium nitride (ScxAl1-xN) thin films are very promising candidates for applications in micro- electromechanical systems due to enhanced piezoelectric properties. To study the influence of deposition parameters on the piezoelectric response, ScxAl1-xN with x = 27% Sc was deposited by reactive sputtering. For determination of piezoelectric constants, platinum electrodes were utilized to measure the piezoelectric deflection via Laser Doppler Vibrometry and compared to finite element simulations. A new electrode design for enhanced accuracy and reduction of computational effort is introduced. Circularly arranged ring electrodes (‘bull's eye’) enable the precise and simultaneous determination of d31 and d33.