Acoustic Wave Electrode Layout for Potential Difference Control
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Solution Overview
Problem
Existing acoustic wave devices face potential damage to electrodes due to unintended potential differences between the upper and lower electrodes, which can occur during manufacturing processes.
Innovation Solution
The acoustic wave device incorporates an overlapping electrode made of the same material as the upper electrode, positioned to overlap the lower electrode through an opening in the piezoelectric layer, ensuring both electrodes are exposed to the same potential, thereby reducing the potential difference and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the piezoelectric layer thickness is reduced to improve device performance, then device performance is improved, but the risk of electrode damage due to potential difference increases
Solution Approach 1:
An overlapping electrode is introduced as an intermediary element between the upper and lower electrodes. This overlapping electrode is positioned to overlap both the upper electrode and the lower electrode, acting as a mediator to equalize potential and prevent harmful potential differences that would otherwise damage the electrodes when the piezoelectric layer is thinned.
Solution Approach 2:
The overlapping electrode is configured to create equipotential regions by overlapping both the upper and lower electrodes. This ensures that the potential is equalized across the electrode structure, eliminating the harmful potential differences that arise when the piezoelectric layer thickness is reduced, thereby preventing electrode damage.
2Reliability
If the piezoelectric layer thickness is reduced to 1 μm or less to improve device performance, then device performance is improved, but unintended potential differences between electrodes occur
Solution Approach 1:
The overlapping electrode serves as an intermediary structure that bridges the upper and lower electrodes. By positioning this intermediate electrode to overlap both electrodes, the potential distribution is controlled and equalized, preventing unintended potential differences even when the piezoelectric layer is thinned to 1 μm or less.
Solution Approach 2:
The overlapping electrode creates equipotential conditions by simultaneously overlapping the upper and lower electrodes. This equipotential configuration ensures that no harmful potential differences develop between electrodes, enabling precise control of electrical potential in ultra-thin piezoelectric layer devices.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively minimizes electrode damage and potential differences, even when the piezoelectric layer thickness is reduced to 1 μm or less, maintaining device integrity and performance.
Implementation Method 1
a piezoelectric layer including a first main surface and a second main surface opposite to the first main surface, an upper electrode on the first main surface of the piezoelectric layer, a lower electrode on the second main surface of the piezoelectric layer
Data Source
AI summary
An acoustic wave device includes a piezoelectric layer including first and second main surfaces, an upper electrode on the first main surface, a lower electrode on the second main surface, and a support facing the second main surface of the piezoelectric layer. The piezoelectric layer includes an opening extending through the piezoelectric layer in a thickness direction in a region overlapping the lower electrode and not overlapping the upper electrode. The acoustic wave device further includes an overlapping electrode on the lower electrode in a region overlapping the opening and made of the same material as the upper electrode.