Piezoelectric acoustic wave characteristics of Pb(In0.5Nb0.5)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystal substrate: A comparative study with and without SiO2 overlay

This paper investigates the excitation and propagation characteristics of a piezoelectric acoustic wave propagating in a rotated Y-cut X-propagating Pb(In0.5Nb0.5)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) relaxor-based ferroelectric single crystal substrate. Numerical simulations were performed to evaluate the acoustic wave properties by FEM software COMSOL. For comparison, two types of structures are taken into consideration: one is the traditional metal electrode/YX-PIN-PMN-PT and the other is silicon dioxide (SiO2) overlay/metal electrode/YX-PIN-PMN-PT substrate. It is shown that shear-horizontal (SH)-type piezoelectric boundary acoustic waves (PBAW) exist in the SiO2 overlay/metal electrode/YX-PIN-PMN-PT substrate and offer a fairly large electromechanical coupling factor K2 of 30%. Compared to a surface acoustic wave excited in the metal electrode/YX-PIN-PMN-PT substrate, enlarged phase velocity and significantly improved quality factor (∼3500) are simultaneously obtained for SH-type PBAW, which are promising for electromechanical transducer applications with high performance.