Parameter characterization of high-overtone bulk acoustic resonators by resonant spectrum method

Resonance Spectrum Characteristics of Effective Electromechanical Coupling Coefficient of High-Overtone Bulk Acoustic Resonator

“…The case discussed in the normal region [4,5,6,7,8,9,10,11,12] is that the thickness of the piezoelectric film and substrate are a half-wavelength and an integer multiple of the half-wavelength at the resonance frequency f 0 , respectively, e.g., the case of the intersections of f 0 and the resonance spectrum shown in blue lines of Figure 2a when f 0 = 3 GHz. The case where the substrate thickness does not equal an integer multiple of the half-wavelength, i.e., the substrate thickness is between any two adjacent discrete values, has not been studied yet; the HBAR will not resonate at f 0 (3 GHz) in such a situation.…”

“…Pao et al [7] discussed the variations of K eff 2 with the substrate thickness for the HBAR with different substrate materials. Zhang et al [8,9,10,11,12] conducted more in-depth research on the effects of the electrode and substrate materials as well as their thickness on the resonance spectrum distribution and the corresponding K eff 2 . These above studies have mainly focused on K eff 2 -frequency distribution of the HBAR, and the effects of each layer’s thickness on K eff 2 have been only carried out in a special case, i.e., the so-called normal region.…”

High-Overtone Bulk Acoustic Resonator

“…The thickness and the nature of electrodes have an influence on the quality factor and the other parameters such as the electromechanical coupling coefficient and the resonance frequency. Many works have been done on this subject [23], [24], [21].…”

Investigations of coupling acoustic matching in multilayer acoustic structures

“…As an extreme example with a thickness larger than 150 lm, the much more acoustic energy is stored in the Si wafer and Q approaches a constant value relating to the Si mechanical losses. 13 We have modeled the acoustic sensor by COMSOL MULTIPHYSICS, a commercial finite-element solver package, to make a comparison with an acoustic resonator consisting of an ideal quarterwavelength matching layer between the piezoelectric film and the Si substrate. The simulation results show that the elastic strain energy density (ESED) in the piezoelectric layer and the substrate of the acoustic sensor is about 1.53 Â 10 4 J/m 3 and 1.34 Â 10 4 J/m 3 , respectively.…”