Electromechanical coupling factor k/sub 35//sup 2/ of thickness-shear mode of the piezoelectric thin films deposited on substrates
An experimental method for characterizing piezoelectric film, which is deposited on a substrate plate to form a thickness-shear wave high-overmode bulk acoustic resonator (HBAR), will be presented in this paper. Based on the parallel and series resonant frequency spectra of the HBAR, the electromechanical coupling factor of the piezoelectric film operating in thickness-shear mode can be evaluated directly. Numerical simulation results of samples consisting of ZnO film on fused SiO/sub 2/ substrate are carried out to show the validity of the method. The effect of the electrodes is compensated by a modified formula.