| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a BAW resonator where both an electromechanical coupling factor and a Q value are made big and a UWB filter using the same. <P>SOLUTION: The BAW resonator includes a base substrate 10, a lower electrode 20 formed on one surface side of the base substrate 10, a piezoelectric layer 30 composed of single crystal KNN formed on a side opposite to the base substrate 10 side in the lower electrode 20, and an upper electrode 40 formed on a side opposite to the lower electrode 20 side in the piezoelectric layer 30. Here, the material of the lower electrode 20 uses a material having favorable lattice consistency with the piezoelectric layer 30 which is better than that with the base substrate 10. Preferably, in the case of the piezoelectric layer 30 composed of KNN, LNO or SRO is used as a material of the lower electrode 20. <P>COPYRIGHT: (C)2010,JPO&INPIT |
