BULK ACOUSTIC WAVE RESONATOR, MANUFACTURING METHOD THEREOF, AND FILTER CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide a BAW resonator capable of preventing generation of cracks on a piezoelectric layer, and reducing the cross sectional area of a resonation region.

SOLUTION: The BAW resonator is provided with a substrate 10, a lower electrode 20 formed on an upper surface 11 of the substrate 10, a piezoelectric layer 30 formed on an upper layer 21 of the lower electrode 20, an insulating layer 40 formed on an upper surface 31 of the piezoelectric layer 30, and an upper electrode 50 formed on an upper surface 41 of the insulating layer 40. The insulating layer 40 is formed on the upper surface 31 of the piezoelectric layer 30 so as to cover a side 32 as one side of the external periphery of the insulating layer 40, and the upper electrode 50 is formed on the upper surface 41 of the insulating layer 40 so as to stride on the insulating layer 40 and its tip is used as a contact part 51 contracting the upper surface 31 of the piezoelectric layer 30.

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