Monocrystalline Nanometric Actuator With Reduced Electrode Gap
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Solution Overview
Problem
Existing nanoscale electromechanical actuators face issues with inefficient interlayer removal, large size, and reduced electromechanical performance due to the use of epitaxial silicon membranes that are not monocrystalline, leading to suboptimal control of polarization voltages and increased mechanical stresses.
Innovation Solution
A method for manufacturing an electromechanical actuator with a monocrystalline mobile electrode, involving a stack of layers bonded through an interlayer, where the mobile electrode is formed by etching a monocrystalline layer and the interlayer is selectively removed to create a small gap, allowing for precise control and reduced mechanical stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If epitaxial silicon membrane is used for the mobile electrode, then the device can be manufactured with suspended membrane structure, but the electromechanical performance is reduced due to non-monocrystalline structure
Solution Approach 1:
The patent changes the material parameter from epitaxial silicon to monocrystalline silicon for the mobile electrode, transforming the crystal structure to eliminate grain boundaries and improve electromechanical performance while maintaining the suspended membrane structure through controlled interlayer removal
Solution Approach 2:
The patent employs a composite layer structure comprising monocrystalline silicon layer, interlayer, and sacrificial layer, where each material serves a specific function: monocrystalline silicon provides high electromechanical performance, interlayer enables controlled release, and sacrificial layer facilitates gap formation through selective removal
2Ease of operation
If the interlayer is completely removed to release the mobile electrode, then the mobile electrode can be suspended, but the removal process is inefficient and leaves residual material
Solution Approach 1:
The patent divides the interlayer into two distinct functional layers: a support portion that remains to anchor the mobile electrode and a sacrificial portion that is completely removed to create the suspension gap. This segmentation enables precise control over which portions are removed and which are retained, achieving complete removal where needed while maintaining structural integrity elsewhere
Solution Approach 2:
The patent introduces a sacrificial layer as an intermediary material between the monocrystalline silicon layer and the substrate. This sacrificial layer is selectively removed through etching to release the mobile electrode, serving as a temporary structural element that facilitates the release process without leaving residual interlayer material in the gap region
3Stability of the object's composition
If the membrane is suspended at several points, then the device structure is stable, but the device size becomes large
Solution Approach 1:
The patent extracts the sacrificial interlayer material from between the mobile electrode and the substrate, removing the intermediary support structure that previously necessitated multi-point suspension. This extraction allows the mobile electrode to be positioned closer to the substrate, reducing device size while maintaining stability through the controlled gap structure
4Ease of manufacture
If a larger gap is maintained between mobile and fixed electrodes, then manufacturing is easier, but electromechanical responsiveness is reduced
Solution Approach 1:
The patent precisely controls the gap parameter by controlling the thickness and removal of the sacrificial interlayer, achieving a minimal gap distance that maximizes electrostatic force and electromechanical responsiveness while still allowing for manufacturable assembly and alignment of the layered structure
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 method results in a nanometric electromechanical actuator with improved electromechanical response, reliability, and durability by using a monocrystalline mobile electrode and a reduced gap, enhancing control and responsiveness.
Implementation Method 1
a non-zero bias is applied between the mobile electrode and the fixed actuation electrode
Data Source
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AI summary
The invention relates to a method (1000) for manufacturing an electromechanical actuator comprising the following steps: • Supplying (1010) a primary stack of layers comprising a single-crystal layer; • Supplying (1020) a secondary stack of layers; • Forming (1030) in the etching layer of at least three pads; • Encapsulating (1040) the three pads with a first encapsulation layer; • Assembling (1060) the primary stack of layers with the secondary stack of layers; • Removing (1070) the first substrate; • Forming (1080) a mobile electrode in the single-crystal layer.