Integrated Acoustic Transducers on Functional Substrates
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Solution Overview
Problem
Conventional methods for fabricating acoustic devices are limited by the need for substrates that are compatible with epitaxial growth processes, restricting the use of substrates with unique physical properties such as electrical, optical, thermal, or magnetic capabilities, and often require stringent process conditions, making it impractical to replicate high-quality piezoelectric thin films on other substrates or heterostructures.
Innovation Solution
The method involves growing high-quality thin film microacoustic devices epitaxially on a host substrate and then using transfer printing to transfer them onto a target functional substrate that provides mechanical support and unique physical properties, decoupling the growth process from the choice of functional substrate, allowing integration of substrates unsuitable for epitaxy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If epitaxial growth is used to grow piezoelectric thin films on substrates, then high-quality piezoelectric transducers can be fabricated, but the substrate must be compatible with epitaxial growth processes which limits the choice of substrates with unique physical properties
Solution Approach 1:
The fabrication process is segmented into two independent stages: (1) epitaxial growth of high-quality piezoelectric thin films on compatible host substrates, and (2) transfer printing of the grown films to target substrates with unique physical properties. This segmentation allows each stage to be optimized independently, resolving the contradiction between film quality and substrate versatility.
Solution Approach 2:
A transfer printing process is introduced as an intermediary step between epitaxial growth and final device assembly. This intermediary enables the decoupling of the growth substrate from the functional substrate, allowing high-quality films to be transferred to substrates with electrical, optical, thermal, or magnetic properties that would be incompatible with direct epitaxial growth.
2Adaptability or versatility
If substrates with unique physical properties (electrical, optical, thermal, magnetic) are used, then enhanced device functionality is achieved, but these substrates are often incompatible with epitaxial growth processes
Solution Approach 1:
The requirement for substrate compatibility with epitaxial growth is extracted from the final device substrate and assigned to a separate host substrate. This allows the functional substrate to be chosen based solely on its unique physical properties without concern for epitaxial compatibility, as the piezoelectric films are transferred rather than grown directly on it.
Solution Approach 2:
The piezoelectric thin films are preliminarily grown on host substrates that are compatible with epitaxial processes, before being transferred to the final functional substrates. This preliminary action on a compatible substrate enables subsequent use of incompatible but functionally superior substrates.
3Reliability
If high-quality piezoelectric films are grown epitaxially, then low-loss acoustic wave propagation is achieved, but the process requires stringent conditions that make replication on other substrates impractical
Solution Approach 1:
Instead of replicating the complex epitaxial growth process on multiple different substrates, the invention creates a master copy of the high-quality piezoelectric film structure on an optimized host substrate, then copies this structure to multiple target substrates via transfer printing. This copying approach preserves the low-loss acoustic properties while avoiding the need to replicate stringent growth conditions.
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 enables the creation of integrated acoustic microstructures that combine the advantages of optimally grown piezoelectric transducers with arbitrary substrates, enabling a wide range of physical phenomena to be coupled with acoustic waves, resulting in enhanced device performance and functionality, such as low-loss propagation of acoustic and spin waves in hybrid phonon-magnon coupled devices.
Implementation Method 1
thin film piezoelectric materials deposited or grown on a supporting substrate have been used to fabricate surface acoustic wave (SAW) and bulk acoustic wave (BAW) devices
Implementation Method 2
surface acoustic wave (SAW) and bulk acoustic wave (BAW) devices
Data Source
AI summary
Method for forming an integrated acoustic device. A thin film piezoelectric acoustic transducer is epitaxially formed on a host substrate and is then transferred to a functional target substrate wherein physical phenomena from the piezoelectric transducer and the arbitrary functional substrate interact to form a hybrid acoustic microsystem comprising the piezoelectric transducer and the arbitrary functional substrate.