THIN FILM PIEZOELECTRIC RESONATOR

摘要

PROBLEM TO BE SOLVED: To provide a thin film piezoelectric resonator whose frequency characteristic such as the resonance frequency can easily be adjusted. SOLUTION: A piezoelectric thin film 2 is formed on a lower face of a first metallic electrode 1 and a semiconductor layer 3 is formed on a lower face of the piezoelectric film 2. The semiconductor layer 3 is doped into an n-type. A second metallic electrode 4 is formed on a lower face of the semiconductor layer 3. A cavity is formed under a lower face of the second metallic electrode 4. The presence of the cavity can prevent the ultrasonic wave stimulated to the piezoelectric film 2 from being absorbed. COPYRIGHT: (C)2005,JPO&NCIPI