Electroacoustic Resonator Stack With Thin Charge Trapping Layer
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Solution Overview
Problem
Existing electroacoustic resonators face challenges in maintaining performance while reducing size and cost, particularly due to parasitic coupling and material thickness impacting parasitic coupling, cost, and space usage, especially in wearable devices with tight size constraints.
Innovation Solution
The use of a thin trap rich layer, typically made of materials like Aluminum Nitride, Silicon Nitride, or Aluminum Oxide, with a thickness between 10 and 200 nanometers, reduces parasitic coupling and enables lower cost stack structures by providing improved electrical and acoustical performance, allowing for carrier aggregation applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick trap rich layer is used to reduce parasitic coupling, then electrical performance is improved, but device size and space usage increase
Solution Approach 1:
The patent changes the thickness parameter of the trap rich layer from conventional thick designs to a thin configuration (less than or equal to 0.125 times the resonance wavelength, or ≤200 nm). This parameter change maintains electrical performance by preserving the charge trapping functionality while significantly reducing the layer thickness to meet size constraints in wearable devices.
Solution Approach 2:
The patent employs a composite material structure consisting of multiple layers including the thin trap rich layer, dielectric layer, piezoelectric layer, and metal layer with interdigital transducer. This composite structure allows each layer to contribute specific functions, enabling the thin trap rich layer to effectively reduce parasitic coupling while maintaining overall device performance through the synergistic combination of materials.
2Volume of moving object
If material thickness is reduced to meet size constraints, then device compactness is improved, but parasitic coupling increases
Solution Approach 1:
The patent optimizes the thickness parameter of the trap rich layer to be greater than or equal to 10 nm and less than or equal to 200 nm (or ≤0.125λ). This specific parameter range ensures that the layer is thin enough to meet size constraints in wearable devices while maintaining sufficient thickness to provide effective charge trapping and reduce parasitic coupling.
Solution Approach 2:
The thin trap rich layer acts as an intermediary between the substrate and the dielectric layer, providing charge trapping functionality that reduces parasitic coupling. This intermediary layer enables the device to achieve compact dimensions while maintaining electrical performance by mediating the interaction between adjacent conductive structures.
3Object-generated harmful factors
If conventional thick trap rich layer structures are used, then parasitic coupling is reduced, but manufacturing cost and space usage increase
Solution Approach 1:
The patent reduces the thickness parameter of the trap rich layer to ≤200 nm, which decreases the amount of material required and simplifies the manufacturing process. This parameter change lowers manufacturing costs while maintaining the charge trapping functionality needed to reduce parasitic coupling, making the device more suitable for mass production in wearable applications.
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 thin trap rich layer maintains performance effectiveness, reduces parasitic surface conduction, and enables smaller, more efficient electroacoustic resonators suitable for wearable devices and other electronic devices with space constraints.
Implementation Method 1
Using a piezoelectric material as a vibrating medium, acoustic resonators operate by transforming an electrical signal wave that is propagating along an electrical conductor into an acoustic wave that is propagating via the piezoelectric material.
Implementation Method 2
a trap rich layer disposed on the conductive substrate layer, the trap rich layer having a thickness less than or equal to 0.125 times the resonance wavelength
Data Source
AI summary
Aspects are provided for electroacoustic resonators with modified charge trapping regions. In one aspect, a device includes a substrate layer, a trap rich layer disposed on the substrate layer, the trap rich layer having a thickness less than or equal to 200 nanometers (nm), a dielectric layer disposed on the trap rich layer, a piezoelectric layer disposed on the dielectric layer, and an interdigital transducer formed in a metal layer disposed on the piezoelectric layer.