Acoustic Resonator Layer Structure for High-Frequency Temperature Stability
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Solution Overview
Problem
BAW devices face challenges in achieving high-frequency operation and wide bandwidth while maintaining low loss and temperature stability, which complicates manufacturing and increases costs.
Innovation Solution
The acoustic resonator is designed with a specific layer structure that includes a bottom laminated structure, a bottom electrode layer, a piezoelectric layer, a top electrode layer, and a frequency-temperature coefficient compensation layer, ensuring most resonance occurs in the compensation layer, allowing for thick layers and simplified manufacturing, with adjustable resonance frequency through etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If extremely thin films are used to achieve high frequency operation above 3 GHz, then the resonant frequency increases, but the manufacturing difficulty increases and mass production yield decreases
Solution Approach 1:
The patent changes the physical parameters of the piezoelectric layer by introducing aluminum nitride doping, which modifies the acoustic velocity and enables thicker films to achieve the same resonant frequency, thereby improving manufacturability while maintaining high-frequency operation
Solution Approach 2:
The patent uses a composite piezoelectric layer structure combining aluminum nitride-doped piezoelectric material with traditional piezoelectric materials, creating a composite structure that achieves both high-frequency performance and ease of manufacture through controlled doping concentrations
2Stability of the object's composition
If piezoelectric film layer is sandwiched between metal electrode and other film layers, then temperature sensitivity is reduced, but the device structure becomes more complex
Solution Approach 1:
The patent modifies the piezoelectric layer's physical and chemical parameters through aluminum nitride doping, which simultaneously improves temperature stability and acoustic performance, reducing the need for additional temperature compensation structures
Solution Approach 2:
The doped piezoelectric layer serves multiple functions: it provides the primary piezoelectric effect for resonance, compensates for temperature variations, and controls acoustic velocity, thereby reducing overall device complexity by combining multiple functions in a single layer
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
The resonator operates at high frequency and wide bandwidth with low loss and low temperature sensitivity, facilitating easy manufacturing and reducing production costs.
Implementation Method 1
a piezoelectric layer, and a top electrode layer are formed on a side of the bottom laminated structure facing away from the substrate
Implementation Method 2
A frequency-temperature coefficient compensation layer is formed on a side of the bottom electrode layer, the piezoelectric layer, and the top electrode layer facing away from the substrate
Data Source
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AI summary
Provided are an acoustic resonator and a manufacturing method thereof, which relate to the technical field of piezoelectric resonators. The manufacturing method of the acoustic resonator includes: forming a bottom laminated structure on a side of a substrate; forming a bottom electrode layer, a piezoelectric layer, and a top electrode layer on a side of the bottom laminated structure facing away from the substrate; and forming a frequency-temperature coefficient compensation layer on a side of the bottom electrode layer, the piezoelectric layer, and the top electrode layer facing away from the substrate.