Elastic wave device

By incorporating dielectric films and low-velocity layers with varying angles into the elastic wave device, the problem of easily deteriorating characteristics of piezoelectric single crystal devices was solved, resulting in more stable device performance.

CN116097563BActive Publication Date: 2026-07-07MURATA MFG CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
MURATA MFG CO LTD
Filing Date
2021-08-19
Publication Date
2026-07-07

AI Technical Summary

Technical Problem

When existing elastic wave devices use piezoelectric single crystals such as LiTaO3, the Z-axis of the crystal is not aligned with the normal direction of the main surface of the piezoelectric substrate, which leads to easy degradation of the characteristics.

Method used

In the elastic wave device, a first dielectric film and a second dielectric film of IDT electrode are set so that they are at different angles α1 and α2 with the main surface of the piezoelectric film, ensuring that α1≠α2, and a low sound velocity layer is set in the edge region of the intersection area to form a sound velocity gradient to suppress stress concentration.

Benefits of technology

It effectively suppressed the degradation of the elastic wave device's characteristics, reduced the occurrence of polarization reversal, and improved the device's stability and performance.

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Abstract

Provided is an elastic wave device in which degradation of characteristics is less likely to occur. An elastic wave device (1) is provided with an IDT electrode (7) on a piezoelectric film (6) whose direction of the Z axis of the crystal is different from the direction of the normal line to the main surface, and a cross region (K) of the IDT electrode (7) has a central region (C) and first and second edge regions (D1, D2), in the first and second edge regions (D1, D2), first and second dielectric films (15, 16) are layered between the piezoelectric film (6) and first and second electrode fingers (13, 14), and when an angle (α1) formed by a first side surface (15a) of the first dielectric film (15) and a main surface (6a) of the piezoelectric film (6) and an angle (α2) formed by a second side surface (16a) of the second dielectric film (16) and the main surface (6a) of the piezoelectric film (6) are set, α1 ≠ α2 between at least one of the plurality of first and second electrode fingers (13, 14) and the piezoelectric film.
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