SURFACE ACOUSTIC WAVE DEVICE INCLUDING JOINED SUBSTRATE HAVING SUPPORTING SUBSTRATE JOINED TO PIEZOELECTRIC ELEMENT SUBSTRATE AND FABRICATING METHOD THEREOF

摘要

PURPOSE: A surface acoustic wave device including a joined substrate having a supporting substrate joined to a piezoelectric element substrate and a fabricating method thereof are provided to improve filter characteristics by restraining generation of spurious waves. CONSTITUTION: A surface acoustic wave device includes a piezoelectric substrate and a supporting substrate. Two or more resonators(10) are formed on a surface of the piezoelectric substrate(20). The supporting substrate(30) is joined to another surface of the piezoelectric substrate. The resonators has exciting parts that overlap each other in the direction of propagating surface acoustic waves. At least a part of the piezoelectric substrate is removed or modified to have different properties between at least one pair of overlapping resonators among the resonators having the overlapping parts.