Lateral Bulk Acoustic Wave Resonator With Thermal Conduction Layer
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Solution Overview
Problem
Laterally excited bulk acoustic wave resonators face challenges with heat dissipation and mechanical ruggedness, particularly in high-frequency applications like 5G NR, where power durability and thermal management are critical but often compromised by the need for expensive acoustic Bragg reflectors.
Innovation Solution
Incorporating a thermally conductive layer with high thermal conductivity, such as aluminum or silicon, between the piezoelectric layer and the support substrate, or over the interdigital transducer electrode, to dissipate heat and enhance mechanical durability while maintaining resonance characteristics, thereby reducing the reliance on costly acoustic Bragg reflectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If acoustic Bragg reflectors are used to improve heat dissipation and mechanical ruggedness, then thermal management and power durability are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts the thermal management function from the complex acoustic Bragg reflector structure and implements it through a simple thermally conductive layer. This layer is deposited directly on the piezoelectric layer to conduct heat away from the interdigital transducer electrode, eliminating the need for expensive and complex Bragg reflector structures while maintaining power durability and thermal management effectiveness
Solution Approach 2:
The patent changes the thermal conductivity parameter by introducing a thermally conductive layer with high thermal conductivity (such as aluminum, copper, or diamond-like materials) onto the piezoelectric layer. This parameter change enables effective heat dissipation from the IDT electrode without requiring complex acoustic Bragg reflector structures, thereby improving power durability while reducing device complexity
2Temperature
If acoustic Bragg reflectors are used to improve heat dissipation, then thermal management is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive acoustic Bragg reflector structures with inexpensive thermally conductive layers that can be deposited using standard thin-film deposition techniques. Materials such as aluminum, copper, or diamond-like carbon are used, which are significantly cheaper than the multi-layer piezoelectric and metallic structures required for Bragg reflectors, thereby reducing manufacturing cost while maintaining effective heat dissipation
Solution Approach 2:
The patent changes the thermal conductivity parameter by introducing a thermally conductive layer with high thermal conductivity (such as aluminum, copper, or diamond-like materials) onto the piezoelectric layer. This parameter change enables effective heat dissipation from the IDT electrode without requiring complex acoustic Bragg reflector structures, thereby improving power durability while reducing device complexity
3Strength
If the piezoelectric layer is directly contacted with the support substrate, then mechanical support is provided, but heat dissipation is insufficient
Solution Approach 1:
The patent makes the thermally conductive layer serve multiple functions: it provides mechanical support to the piezoelectric layer (maintaining structural integrity) while simultaneously acting as a heat sink to conduct heat away from the interdigital transducer electrode. This multi-functional layer eliminates the need for separate support and thermal management structures, effectively resolving the contradiction between mechanical support and heat dissipation
Solution Approach 2:
The thermally conductive layer acts as an intermediary between the piezoelectric layer and the support substrate. It is deposited directly onto the piezoelectric layer, providing both mechanical support and thermal conduction pathways. This intermediary layer effectively transfers heat from the IDT electrode through the piezoelectric layer to the support substrate, resolving the heat dissipation insufficiency while maintaining mechanical support
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 enables effective thermal dissipation and power durability for high-frequency applications, improving the performance of acoustic wave filters in 5G NR and other high-frequency bands without the need for expensive acoustic Bragg reflectors, thus offering a cost-effective solution for thermal management.
Implementation Method 1
a thermally conductive layer arranged at least partially in contact with the piezoelectric layer
Implementation Method 2
an interdigital transducer electrode arranged on the piezoelectric layer
Data Source
AI summary
An acoustic wave device is disclosed. The acoustic wave device can include a piezoelectric layer, an interdigital transducer electrode on a first side of the piezoelectric layer, an air cavity on a second side of the piezoelectric layer that is opposite to the first side of the piezoelectric layer, and a thermally conductive layer. The acoustic wave device is configured to laterally excite a bulk acoustic wave. The thermally conductive layer is configured to dissipate heat associated with exciting the laterally excited bulk acoustic wave.