Fracture limit in thin-film piezoelectric-on-substrate resonators: Silicon VS. diamond

In this work, lateral-extensional thin-film piezoelectric-on-substrate (TPoS) resonators, fabricated on both silicon and diamond, are driven beyond their bifurcation point in order to study the maximum allowable energy density before the resonator fractures. A method is presented to measure the stored energy of the resonator at different drive levels. The average measured critical energy density of the resonator (the stored energy at bifurcation) on silicon substrate is ~5.2×10⁵J/m³ for a specific resonator design while it is ~2.7×10⁵J/m³ for a similar device fabricated on ultrananocrystalline diamond. On the other hand, the resonator on diamond withstands energy densities more than 2 times larger than the resonator on silicon before devices fracture and fail mechanically.