| 摘要 |
PROBLEM TO BE SOLVED: To provide a piezoelectric thin-film resonator the temperature stability of the resonance frequency of which is enhanced, without impairing the electromechanical coupling coefficient and the acoustic quality factor. SOLUTION: The piezoelectric includes a substrate 12 made of a silicon single crystal, an insulation layer 13 formed thereon, and a piezoelectric laminated structure 14 formed thereon. A vibration part 21 of the piezoelectric thin-film resonator is configured by including part of the insulation layer 13 and part of the piezoelectric laminated structure 14. The piezoelectric laminated structure 14 is formed, by laminating a piezoelectric film 16 and an upper electrode 17, in this order. The substrate 12 includes a via-hole 20 for forming an air gap for permitting vibration of the vibration part 21 in the region of the substrate 12, corresponding to the vibration part 21. The principal component of the piezoelectric film 16 is aluminum nitride, the principal component of the lower electrode 15 and the upper electrode 17 is made of molybdenum, and the principal component of the insulation layer 13 is made of silicon oxide. The thickness t of the piezoelectric film 16 and the thickness t' of the insulation layer satisfy the relation 0.1≤t'/t≤0.5. COPYRIGHT: (C)2005,JPO&NCIPI
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