Acoustic Wave Reflector Layout for Lower Parasitic Capacitance
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Solution Overview
Problem
Existing acoustic wave devices with continuous DBR structures suffer from parasitic capacitance issues due to their design, which affects their performance in advanced communication equipment requiring multiple frequency bands and bandwidths.
Innovation Solution
The development of an acoustic wave device with a multilayer structure featuring multiple separated reflecting elements and a tapered electrode configuration, which reduces parasitic capacitance by altering the arrangement of acoustic wave reflective material layers and electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a continuous DBR structure is used in acoustic wave devices, then the acoustic wave reflection performance is improved, but parasitic capacitance increases affecting communication performance
Solution Approach 1:
The continuous DBR structure is divided into multiple separate reflecting elements. Each reflecting element consists of alternating high acoustic impedance layers (e.g., NbN, TaN) and low acoustic impedance layers (e.g., AlN, SiN), but they are spatially separated rather than continuous. This segmentation maintains acoustic wave reflection performance while reducing parasitic capacitance between electrodes and the DBR structure.
Solution Approach 2:
The electrode configuration is optimized locally with tapered structures that have varying thickness. The electrodes have different thicknesses in different regions (tapered from thick to thin), allowing local optimization of electrical properties while maintaining overall device performance. This local quality variation helps reduce parasitic capacitance while preserving acoustic wave reflection.
2Adaptability or versatility
If communication equipment is designed to handle multiple frequency bands and bandwidths, then communication versatility is improved, but device complexity increases
Solution Approach 1:
The acoustic wave device with separated reflecting elements and tapered electrodes serves multiple communication frequency bands and bandwidths simultaneously. The same basic structure can be tuned for different applications (e.g., LTE, 5G, Wi-Fi) by adjusting the dimensions, materials, and spacing of the reflecting elements, providing universal functionality across multiple communication standards without requiring completely different device architectures.
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 improves the overall performance of the acoustic wave device by minimizing parasitic capacitance and enhancing its ability to handle complex communication requirements across various frequency bands and bandwidths.
Implementation Method 1
forming a sensing layer on the first substrate, forming a bottom electrode on a side of the sensing layer
Implementation Method 2
forming a reflecting element on the second substrate, wherein the reflecting element includes multiple acoustic wave reflective material layers
Data Source
AI summary
A method for forming an acoustic wave device, including steps of: forming an acoustic wave sensing part and an acoustic wave reflecting part, wherein the step of forming the acoustic wave sensing part includes: providing a first substrate, forming a sensing layer on the first substrate, forming a bottom electrode on a side of the sensing layer, and forming a filling layer on the sensing layer and the bottom electrode; and wherein the step of forming the acoustic wave reflecting part includes: providing a second substrate, forming a reflecting element on the second substrate, and forming a cover layer on the reflecting element; joining the acoustic wave sensing part and the acoustic wave reflecting part; removing the first substrate; and forming a top electrode on another side of the sensing layer, wherein the bottom electrode, the top electrode and the reflecting element are arranged correspondingly to each other.