Acoustic Wave Resonator Structure for Stable Frequency Control
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Solution Overview
Problem
Existing acoustic wave devices, such as bulk acoustic wave resonators, face challenges in achieving precise control over resonance frequency and stability due to limitations in the characteristics and thickness of the piezoelectric layer and electrode overlap, which can lead to defects and contamination issues during manufacturing.
Innovation Solution
The acoustic wave device incorporates a piezoelectric layer with an upper and lower surface, an upper electrode, a support layer made of non-monocrystalline insulating material, and a lower cover, fabricated using epitaxial growth and deposition methods, with a manufacturing process that includes forming a substrate, removing it to expose the lower surface, and creating cavities for resonant deformation, thereby enhancing the control over resonant regions and reducing contamination risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the piezoelectric layer thickness and electrode overlap are controlled to achieve precise resonance frequency, then manufacturing complexity and risk of defects increase
Solution Approach 1:
A support layer is introduced between the piezoelectric layer and the lower electrode/cover assembly. This intermediary layer simplifies the manufacturing process by providing a stable platform during fabrication, reducing the complexity of directly controlling piezoelectric layer thickness and electrode overlap for precise resonance frequency.
Solution Approach 2:
The device is divided into distinct functional layers: piezoelectric layer, support layer, lower electrode, and lower cover. This segmentation allows each component to be optimized and manufactured independently, reducing overall manufacturing complexity while maintaining precise resonance frequency control through the coordinated design of these separate elements.
2Measurement precision
If the piezoelectric layer thickness is reduced to improve resonance frequency control, then structural strength and reliability decrease
Solution Approach 1:
The support layer serves as a mediator that compensates for the reduced structural strength of the thinner piezoelectric layer. It provides mechanical support and stability, ensuring the overall device reliability is maintained even when the piezoelectric layer is made thinner for better resonance frequency control.
Solution Approach 2:
The device employs a composite structure combining the piezoelectric layer with the support layer, lower electrode, and lower cover. This composite design allows the thinner piezoelectric layer to function effectively for resonance frequency control while the other layers provide the necessary structural strength and reliability.
3Productivity
If traditional manufacturing methods are used without support layer, then production efficiency is maintained, but defect rate and contamination risk increase
Solution Approach 1:
The support layer is formed in advance before the lower electrode and lower cover are assembled. This preliminary action creates a stable platform that prevents defects and contamination during subsequent manufacturing steps, maintaining high production efficiency while reducing the defect rate.
Solution Approach 2:
The support layer acts as a protective intermediary during the manufacturing process, preventing direct contact between the piezoelectric layer and the lower electrode/cover assembly. This reduces contamination risk and defect formation while allowing traditional manufacturing methods to proceed efficiently.
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 allows for improved control over resonance frequency and stability, reducing defects and contamination, and providing a robust structure for efficient energy conversion from electrical to mechanical waves, while minimizing stress and disconnection issues.
Implementation Method 1
The bulk acoustic wave resonance device includes two electrodes and a piezoelectric layer is disposed therebetween, such that the sound waves oscillate in the piezoelectric layer to form a standing wave
Implementation Method 2
forming a piezoelectric layer by epitaxial growth
Data Source
AI summary
An acoustic wave device, includes piezoelectric layer having an upper piezoelectric surface and a lower piezoelectric surface; an upper electrode formed on the upper piezoelectric surface; a lower electrode; a support layer including a non-monocrystalline insulating material; and a lower cover, wherein the lower electrode and the support layer formed between the lower cover and the lower piezoelectric surface.