The BAW and SAW coupling analysis of patterned piezoelectric films as inter-digital transducers on diamond substrates using delta-function model

Patterned piezoelectric films as inter-digital transducer (PP-IDT) structures on diamond substrates have been attracting extensive attention due to the increased working frequency, electromechanical coupling, and quality factor of piezoelectric devices. In this study, by conceiving every single patterned piezoelectric IDT bar as the longitudinal bulk acoustic wave (BAW) vibrating source, we study how the BAW excites and couples with the surface acoustic wave (SAW) on the surface of diamond substrates and resonates simultaneously. The classic delta-function model of the SAW and electric impedance theory of the film bulk acoustic resonator were innovatively combined to develop this conception. Resonating frequency and corresponding piezoelectric IDT thickness were calculated using MATLAB software based on the developed delta-function model. The resonance results coincided well with finite element method simulations, validating this conception and the developed delta-function model for PP-IDT structures. (C) 2021 Author(s).

Automated summary

Patterned piezoelectric films as inter-digital transducer (PP-IDT) structures on diamond substrates have been studied for their increased working frequency, electromechanical coupling, and quality factor. By considering each patterned piezoelectric IDT bar as a longitudinal bulk acoustic wave vibrating source, researchers investigated how the BAW excites and couples with the surface acoustic wave on the surface of diamond substrates. The developed delta-function model combined with electric impedance theory was used to calculate resonance frequency and corresponding piezoelectric IDT thickness, with results validating the developed model for PP-IDT structures.