High-Order Acoustic Resonators With Thick Electrodes for 5 GHz Operation
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Solution Overview
Problem
Existing acoustic resonators, particularly film bulk acoustic resonators (FBARs), face challenges in achieving high-frequency operation while maintaining adequate electrical conductance and structural strength, especially as technology advances towards 5G and beyond communication networks.
Innovation Solution
The development of acoustic resonator devices that incorporate thick electrodes, allowing for operation in higher order thickness extension modes (e.g., TE2 and TE3) by introducing additional stress half-waves within the electrode layers, thereby enabling high-frequency operation without significantly reducing electrode thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If electrode thickness is reduced to achieve high-frequency operation, then resonant frequency increases, but electrical conductance and structural strength deteriorate
Solution Approach 1:
The patent changes the operational mode parameter from fundamental mode to higher-order thickness extension modes (TE2, TE3, etc.), which allows the resonator to operate at high frequencies while maintaining thicker electrodes. This parameter change in the resonance mode enables simultaneous achievement of high resonant frequency and adequate electrical conductance.
Solution Approach 2:
The patent introduces additional stress half-waves within the electrode layers by operating in higher-order modes, effectively adding dimensional complexity to the stress distribution. This allows the electrodes to be thicker while still supporting the required high-frequency operation, thus improving electrical conductance without sacrificing frequency performance.
2Speed
If electrode thickness is reduced to achieve high-frequency operation, then resonant frequency increases, but structural strength deteriorates
Solution Approach 1:
By changing the resonance mode parameter to higher-order thickness extension modes, the patent enables high-frequency operation with thicker electrodes, thereby maintaining structural strength while achieving the required resonant frequency performance.
Solution Approach 2:
The introduction of additional stress half-waves in higher-order modes provides a more distributed stress pattern throughout the electrode thickness, enhancing structural strength while enabling high-frequency operation.
3Reliability
If additional stress half-waves are introduced in electrode layers, then electrical conductance improves, but device complexity increases
Solution Approach 1:
The patent utilizes parameter changes in the resonance mode (to TE2, TE3, etc.) to naturally produce the desired stress distribution with multiple half-waves. This approach achieves improved electrical conductance through a fundamental mode change rather than through complex structural modifications.
Solution Approach 2:
The higher-order thickness extension modes serve multiple functions simultaneously: they provide the necessary stress distribution for improved electrical conductance, maintain high resonant frequency, and ensure adequate structural strength, thereby reducing the need for separate design optimizations.
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 approach allows for improved electrical conductance and structural strength, enabling the resonators to operate efficiently at high frequencies (e.g., over 5 GHz) with thicker electrodes, which enhances their performance and usability in various applications.
Implementation Method 1
an acoustic resonator device includes a piezoelectric layer disposed between a first electrode and a second electrode
Implementation Method 2
The thickness of the first electrode and the second electrode allows the device to operate according to a second (or higher order) thickness extension mode
Data Source
AI summary
The subject technology is related to acoustic resonators. More specifically, an embodiment of the subject technology provides an acoustic resonator device that includes a piezoelectric layer disposed between a first electrode and a second electrode. The total thickness of the first electrode, the second electrode, and the third electrode allows the device to operate according to a second (or higher order) thickness extension mode. There are other embodiments as well.