Elastic wave device
By setting a stress relief layer on the piezoelectric layer, the polarization reversal problem caused by stress concentration in the piezoelectric substrate stack-up structure is solved, thereby improving the reliability and performance stability of the elastic wave device.
CN114731147BActive Publication Date: 2026-07-07MURATA MFG CO LTD
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- MURATA MFG CO LTD
- Filing Date
- 2020-12-02
- Publication Date
- 2026-07-07
AI Technical Summary
Technical Problem
In elastic wave devices with a piezoelectric substrate in a stacked structure, stress concentration occurs in the piezoelectric layer due to the difference in the coefficient of linear expansion between the piezoelectric layer, the IDT electrode, and the connecting wiring, which may lead to polarization reversal.
Method used
A stress relief layer is set on the piezoelectric layer, located between the connection part and the piezoelectric layer, to avoid stress concentration areas and suppress the occurrence of polarization reversal.
Benefits of technology
It effectively suppressed the occurrence of polarization reversal and improved the reliability and performance stability of the elastic wave device.
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Smart Images
Figure CN114731147B_ABST
Abstract
Inhibiting occurrence of domain inversion. In an elastic wave device (1), a plurality of first electrode fingers (61) and a plurality of second electrode fingers (62) are provided on a piezoelectric layer (5). A plurality of third electrode fingers (63) and a plurality of fourth electrode fingers (64) are provided on the piezoelectric layer (5). A connection portion includes a second bus bar (82) and a third bus bar (83). The second bus bar (82) is provided on the piezoelectric layer (5) and connected to one end of the plurality of second electrode fingers (62). The third bus bar (83) is provided on the piezoelectric layer (5) and connected to one end of the plurality of third electrode fingers (63). A stress relief layer (9) is provided between the connection portion and the piezoelectric layer (5). In a plan view from a thickness direction (D0) of a support substrate (2), the stress relief layer (9) does not reach gaps (102) between the plurality of first electrode fingers (61) and the second bus bar (82) and gaps (103) between the plurality of fourth electrode fingers (64) and the third bus bar (83).
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