Acoustic Wave Layer Structure for Wider Fractional Bandwidth
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing acoustic wave devices face challenges in achieving a wide fractional bandwidth, which is essential for applications like bandpass filters, due to limitations in confining acoustic waves effectively.
Innovation Solution
The acoustic wave device incorporates a high acoustic velocity structure with a low acoustic velocity layer made of dielectric materials having a lower Young's modulus than silicon oxide, combined with a piezoelectric layer, allowing for effective wave confinement and increased fractional bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a low acoustic velocity layer made of silicon oxide is used, then acoustic waves are effectively confined in the piezoelectric layer, but the fractional bandwidth remains narrow
Solution Approach 1:
The invention changes the material parameter (Young's modulus) of the low acoustic velocity layer from silicon oxide to materials with lower Young's modulus (such as aluminum titanate, boron nitride, or carbon-containing silicon oxide). This parameter change enables both effective acoustic wave confinement and increased fractional bandwidth, resolving the technical contradiction between reliability and adaptability.
2Device complexity
If conventional materials are used in the low acoustic velocity layer, then the device structure is simple, but the fractional bandwidth cannot be sufficiently increased
Solution Approach 1:
The invention employs composite material selection for the low acoustic velocity layer, using materials such as aluminum titanate, boron nitride, or carbon-containing silicon oxide that combine low acoustic velocity properties with low Young's modulus. This composite material approach achieves wide fractional bandwidth while maintaining a relatively simple layered structure.
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 enhances the fractional bandwidth of acoustic wave devices by effectively confining acoustic waves in the piezoelectric layer, as demonstrated by the use of materials like aluminum titanate, boron nitride, and carbon-containing silicon oxide, compared to silicon oxide.
Implementation Method 1
effective confinement of acoustic waves in the piezoelectric layer to increase the Q value
Implementation Method 2
a piezoelectric layer directly or indirectly on the low acoustic velocity layer
Data Source
AI summary
An acoustic wave device includes a high acoustic velocity structure, a low acoustic velocity layer on the high acoustic velocity structure, a piezoelectric layer directly or indirectly on the low acoustic velocity layer, and an electrode on the piezoelectric layer. The low acoustic velocity layer is made of a dielectric material having a lower Young's modulus than silicon oxide, or includes the dielectric material as a main component.