Patent ID: 9048813
Filing Date: 2015-06-02
Classification: H03H

Abstract:
1. An acoustic wave device comprising: a piezoelectric substrate; a comb-shaped electrode disposed on the piezoelectric substrate and configured to excite a Rayleigh wave as a main acoustic wave; a first dielectric film disposed above the piezoelectric substrate, covering the comb-shaped electrode, and contacting side surfaces of electrode fingers of the comb-shaped electrode, a speed of a transverse wave propagating through the first dielectric film being lower than a speed of the Rayleigh wave excited by the comb-shaped electrode; and a second dielectric film including a first portion and a second portion, the first portion being disposed between the electrode fingers of the comb-shaped electrode and between the piezoelectric substrate and the first dielectric film, the second portion disposed above the comb-shaped electrode and between the comb-shaped electrode and the first dielectric film, a speed of the transverse wave propagating through the second dielectric film being higher than the speed of the Rayleigh wave exited by the comb-shaped electrode.