PIEZOELECTRIC VIBRATION DEVICE, METHOD OF MANUFACTURING THE SAME, AND METHOD OF ADJUSTING RESONANT FREQUENCY

摘要

A method of manufacturing a piezoelectric vibration device having a surface acoustic wave element includes a step of forming a functional film adapted to increase a velocity of a wave on a surface of the surface acoustic wave element. Further, the Young's modulus of the functional film is higher than the Young's modulus of each of the excitation electrode and the piezoelectric body, and the density of the functional film is lower than the density of each of the excitation electrode and the piezoelectric body. Thus, it is possible to develop the frequency rise due to the elastic modulus rise while suppressing the influence of the frequency drop due to the mass attachment effect to thereby raise the resonant frequency of the surface acoustic wave element.