Single-Crystal FBAR Film Transfer for Acoustic Isolation
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Solution Overview
Problem
Conventional film bulk acoustic resonators (FBARs) fabricated with polycrystalline piezoelectric materials are unsuitable for advanced wireless applications due to low piezoelectric coefficients and figures of merit, and the fabrication of single-crystalline semiconductor materials is hindered by thick material deposition and inefficient etching processes.
Innovation Solution
A device comprising a substrate with a cavity and a single-crystalline semiconductor material grown epitaxially over a lattice-matched two-dimensional material, which is then transferred to a performance substrate, bypassing the need for back-etching and allowing for acoustic isolation and efficient piezoelectric material utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If single-crystalline semiconductor material is grown epitaxially over lattice-matched two-dimensional material and transferred to performance substrate, then manufacturing precision and piezoelectric performance are improved, but device complexity and fabrication process difficulty increase
Solution Approach 1:
The fabrication process is divided into separate stages: growing single-crystalline material on a lattice-matched two-dimensional material substrate, transferring it to the performance substrate, and then completing the device fabrication. This segmentation allows each stage to be optimized independently, achieving high crystal quality without compromising the final device performance.
Solution Approach 2:
A lattice-matched two-dimensional material serves as an intermediary substrate during the epitaxial growth process. This intermediary layer enables the growth of high-quality single-crystalline semiconductor films by providing a lattice-matched template, which can then be transferred to the final performance substrate, avoiding the need to grow directly on the complex final substrate structure.
2Ease of manufacture
If conventional polycrystalline piezoelectric materials are used in FBARs, then fabrication process is simpler, but piezoelectric coefficients and figures of merit are reduced
Solution Approach 1:
The invention changes the fundamental parameter of crystal structure from polycrystalline to single-crystalline by using epitaxial growth on lattice-matched two-dimensional materials. This parameter change dramatically improves piezoelectric coefficients and figures of merit while maintaining compatibility with existing FBAR device architectures and fabrication processes.
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 solution enables the production of thin, high-quality single-crystalline semiconductor films suitable for advanced wireless applications, such as 5G mobile networks, by eliminating defects and improving piezoelectric performance.
Implementation Method 1
a single-crystalline semiconductor material grown epitaxially over a lattice-matched two-dimensional material
Implementation Method 2
the first contact and the single-crystalline semiconductor material form a first Ohmic contact
Data Source
AI summary
Resonators comprising a single-crystalline semiconductor, and related systems and methods, are generally described.