公开(公告)号：US20210288628A1

公开(公告)日：2021-09-16

申请号：US17184910

申请日：2021-02-25

Applicant: TAIYO YUDEN CO., LTD.

Inventor： Takuya NISHIMURA ,  Toshiharu NAKAZATO ,  Toshio NISHIZAWA ,  Naoki TAKAHASHI

IPC: H03H9/02 ,  H03H9/145 ,  H03H9/64

Abstract: An acoustic wave device includes a support substrate, a piezoelectric layer located over the support substrate, a pair of comb-shaped electrodes disposed on the piezoelectric layer and including electrode fingers exciting an acoustic wave, a temperature compensation film interposed between the support substrate and the piezoelectric layer, having a thickness equal to or less than 2 times an average pitch of the electrode fingers, and having a temperature coefficient of elastic constant opposite in sign to that of the piezoelectric layer, and a boundary layer interposed between the support substrate and the temperature compensation film and having a thickness equal to or greater than 2.2 times the average pitch, an acoustic velocity of a lateral wave propagating through the boundary layer being less than that of a lateral wave propagating through the support substrate and greater than that of a lateral wave propagating through the temperature compensation film.