| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a thin film acoustic resonator which is reduced in spurious excitation and improved in characteristic and durability. <P>SOLUTION: The thin film acoustic resonator has a sandwich structure formed by laminating layers so that a piezoelectric thin film layer 22 is sandwiched between a lower electrode layer 23 and an upper electrode layer 21 and further joining a contact electrode layer 24 to the lower electrode layer 23. The contact electrode layer 24 is formed annularly around a pit 12 formed in a substrate 11 so as to allow the sandwich structure to vibrate, and joined to the substrate 11. Here, 0.01×S2≤S1≤0.5×S2, where S1 represents the plane area of a part of the contact electrode layer 24 which comes into contact with the substrate 11 and S2 represents the plane area of the lower electrode layer 23. The contact electrode layer 24 is made of a material containing at least one kind selected out of Ti, Cr, Ni and Ta and the lower electrode layer is made of a material containing at least one kind selected out of Au, Pt, W and Mo. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
