Surface acoustic wave device and method of fabricating the same
View Patent ↗A surface acoustic wave device includes a piezoelectric substrate; comb electrodes provided on a first surface of the piezoelectric substrate; and an insulating film provided on at least one of the first surface of the piezoelectric substrate and a second surface thereof opposite to the first surface, the insulating film having a thickness greater than that of the piezoelectric substrate and having a linear expansion coefficient smaller than that of the piezoelectric substrate in a direction of propagation of a surface acoustic wave.
1. A surface acoustic wave device comprising:
a piezoelectric substrate;
comb electrodes provided on a first surface of the piezoelectric substrate;
a resin portion that defines cavities above the comb electrodes; and
an insulating film provided on the first surface of the piezoelectric substrate so as to cover the resin portion,
the insulating film having a thickness greater than that of the piezoelectric substrate and having a linear expansion coefficient smaller than that of the piezoelectric substrate in a direction of propagation of a surface acoustic wave.
2. The surface acoustic wave device according to claim 1 , wherein the insulating film is provided on both the first surface of the piezoelectric substrate and a second surface thereof opposite to the first surface.
3. The surface acoustic wave device according to claim 1 , wherein the insulating film includes ceramics.
4. The surface acoustic wave device according to claim 1 , wherein the insulating film includes ceramics that contains glass.