Bulk acoustic wave resonator structure and fabriating method
AssigneeShenzhen Newsonic Technologies Co., Ltd.
InventorJian WANG
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Abstract
A film bulk acoustic resonator (FBAR) structure includes a bottom cap wafer, a piezoelectric layer disposed on the bottom cap wafer, a bottom electrode disposed below the piezoelectric layer, and a top electrode disposed above the piezoelectric layer. Portions of the bottom electrode, the piezoelectric layer, and the top electrode that overlap with each other constitute a piezoelectric stack. The FBAR structure further includes a lower cavity disposed below the piezoelectric stack. A projection of the piezoelectric stack is located within the lower cavity.
Claims21
1-20. (canceled)
A bulk acoustic wave resonator structure, comprising:
- a bottom cap wafer;
- a piezoelectric layer disposed on the bottom cap wafer;
- a bottom electrode disposed below the piezoelectric layer;
- a top electrode disposed above the piezoelectric layer, wherein portions of the bottom electrode, the piezoelectric layer, and the top electrode that overlap with each other constitute a piezoelectric stack;
- a sacrificial layer disposed between the bottom cap wafer and the piezoelectric layer;
- a lower cavity disposed within the sacrificial layer and below the piezoelectric stack;
- a bottom bonding layer disposed between the sacrificial layer and the bottom cap wafer, the bottom bonding layer including a protruding structure integrally formed as a part of the bottom bonding layer and protruding towards the piezoelectric layer and surrounding the lower cavity, and an entire bottom surface of the bottom bonding layer facing the bottom cap wafer being planarized;
- and
- a boundary layer continuously disposed between the bottom bonding layer and the piezoelectric layer and overlaying the protruding structure of the bottom bonding layer,
- wherein a projection of the piezoelectric stack is located within the lower cavity.
Dependencies are inferred from the claim text.