| 摘要 |
<p>A device using a Lamb wave is provided which has the structure in which spurious by undesired modes can be effectively suppressed. A Lamb wave device (1) has a base substrate (2); a piezoelectric thin film (3) which is formed on the base substrate (2) and which has a floating portion floating above the base substrate (2), the floating portion having a first surface (3a) facing the base substrate (2) and a second surface (3b) opposite to the first surface (3a); and an IDT electrode (4) disposed on at least one of the first and the second surfaces of the piezoelectric thin film (3). The piezoelectric thin film (3) is formed of LiTaO 3 or LiNbO 3 , and the c axis of the piezoelectric thin film (3) is set in approximately the same direction as that of the normal line to the first and the second surfaces of the piezoelectric thin film (3), and the crystal structure of the piezoelectric thin film (3) is a rotation twin crystal having the c axis functioning as the rotation axis.</p> |
