| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a Lamb wave device that reduces a variation in frequency. <P>SOLUTION: A Lamb wave device 102 includes: a piezoelectric thin film 106; an IDT electrode 108 provided on the major surface of the piezoelectric thin film 106; and a support structure 122 that supports a laminated body 104 of the IDT electrode 108 and the piezoelectric thin film 106 and has a cavity 180 forming a clearance from the laminated body 104. A thickness h of the piezoelectric thin film 106 and a pitch p of a finger 110 of the IDT electrode 108 are selected so that a higher-mode Lamb wave with a sound velocity of at least 5000 m/s is excited at a desired frequency. The crystal orientation of the piezoelectric thin film 106 is selected so as to sufficiently reduce an etching rate for a hydrofluoric acid at an underside 1062 of the piezoelectric thin film 106 on the support structure 122. <P>COPYRIGHT: (C)2010,JPO&INPIT |
