Single-Crystal Resonator Fabrication With Split Substrate Removal
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Solution Overview
Problem
The existing methods for forming resonators in radio frequency filters face challenges due to lattice mismatch between the lower electrode layer and the substrate, leading to poor quality piezoelectric layers, and the difficulty in removing single crystal substrates used for epitaxial growth.
Innovation Solution
A method involving ion implantation to create a damaged layer in the single crystal substrate, allowing for its partial removal through heating and subsequent trimming or etching, facilitating the growth of high-quality single crystal piezoelectric layers and reducing the complexity of substrate removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single crystal substrate is used to grow high-quality piezoelectric layers, then the quality of the piezoelectric layer is improved, but the difficulty of removing the substrate increases
Solution Approach 1:
The single crystal substrate is segmented into two parts: a first substrate portion that is removed and a second substrate portion that remains. This is achieved by forming a separation layer at a specific depth within the substrate, allowing the upper portion to be detached and removed while retaining the lower portion with the piezoelectric layer
Solution Approach 2:
The separation layer is formed in advance within the single crystal substrate before the piezoelectric layer is grown. This preliminary action creates a predetermined weak plane that facilitates subsequent substrate removal, enabling easy separation along the ion-implanted depth without compromising the quality of the piezoelectric layer
2Device complexity
If the lower electrode layer is formed on the substrate first, then the fabrication process is simplified, but the piezoelectric layer quality deteriorates due to lattice mismatch
Solution Approach 1:
The lower electrode layer formation step is extracted from the traditional deposition sequence and replaced by direct growth of the piezoelectric layer on the single crystal substrate. The lower electrode layer is subsequently formed on the piezoelectric layer rather than on the substrate, eliminating the lattice mismatch problem while maintaining process simplicity
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 rapid and effective removal of the single crystal substrate, improving the quality of the resonator by avoiding lattice mismatch issues and allowing for direct electrode formation on the piezoelectric layer, thus enhancing the performance of radio frequency filters.
Implementation Method 1
ion implantation is performed on the first single crystal substrate by the single crystal piezoelectric layer to sequentially divide the first single crystal substrate into a first layer, a damaged layer located above the first layer, and a second layer located above the damaged layer
Implementation Method 2
the first layer is split from the second layer at the damaged layer by heating process
Data Source
AI summary
The present application provides a resonator and a preparation method for a resonator, and relates to the technical field of semiconductors. The method involves introducing a first single crystal substrate to facilitate the epitaxial growth of a high-quality single crystal piezoelectric layer on the first single crystal substrate, and firstly performing ion implantation on the first single crystal substrate to form a damaged layer at a certain depth within it. Therefore, while the first single crystal substrate is removed, it is firstly possible to adopt the heating process, and after the first single crystal substrate is subjected to high-temperature treatment, a first layer and a second layer are split at the damaged layer, thereby a part of the first single crystal substrate is firstly removed, and then the remaining part of the first single crystal substrate is removed by trimming, etching, and other modes. By cooperation of two removing modes, the rapid removal of the first single crystal substrate is achieved, and the difficulty of removing the first single crystal substrate is effectively reduced.