Tapered Electrode Nanopore Junctions for Reduced Sheet Resistance
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Solution Overview
Problem
Conventional nanopore-based devices face challenges in reliable mass production and accurate analysis due to fabrication issues such as electrical shorting, incomplete wetting, and high sheet resistance, which hinder the effective sequencing of nucleic acid molecules.
Innovation Solution
The use of tunneling junctions with sloping or curved sidewalls for electrodes and multiple insulating layers to prevent shorting, combined with tapered electrodes to reduce sheet resistance, enhances the reliability and manufacturability of nanopore devices for molecular analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electrodes are deposited with sharp sidewalls for precise patterning, then alignment precision is improved, but electrical shorting increases due to incomplete coverage of thin dielectric layers
Solution Approach 1:
The patent applies curvature by replacing sharp sidewalls with rounded or sloped sidewalls on electrode structures. This geometric modification allows thin dielectric layers to conformally cover the electrode surfaces, eliminating voids and preventing electrical shorting while maintaining sufficient patterning precision for nanopore fabrication.
2Manufacturing precision
If electrode thickness is reduced to ease patterning, then manufacturing precision is improved, but sheet resistance increases
Solution Approach 1:
The patent applies local quality by varying electrode thickness across different regions: thinner electrodes in the nanopore region for precise patterning and thicker electrodes in contact regions for low sheet resistance. This spatially differentiated design optimizes both patterning ease and electrical performance.
3Measurement precision
If nanopore dimensions are reduced to enable ionic current sequencing, then measurement precision is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-forming rounded electrode sidewalls and optimized geometries before nanopore fabrication. This preparatory structuring simplifies subsequent nanopore creation processes and enables precise dimensional control at the nanometer scale required for accurate ionic current sequencing.
4Measurement precision
If thin dielectric layers are used to achieve tunneling junctions, then measurement precision is improved, but reliability worsens due to increased shorting risk
Solution Approach 1:
The patent applies curvature to electrode sidewalls to enable complete conformal coverage of thin dielectric layers. The rounded geometry eliminates sharp corners where voids would form, ensuring uniform dielectric coverage that prevents electrical shorting while maintaining the thin layer thickness necessary for tunneling current detection.
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 significantly reduces electrical shorting and improves the yield of tunneling junctions, allowing for more accurate and reliable analysis of molecules by maintaining the integrity of the insulating layer and optimizing electrode geometry for better coverage and reduced resistance.
Implementation Method 1
an insulating layer disposed between the first electrode and the second electrode
Implementation Method 2
The orbitals of the nucleotide will allow electrons to transfer from one electrode to the other, creating a tunneling current
Data Source
AI summary
Embodiments of the present technology may allow for improved and more reliable tunneling junctions and methods of fabricating the tunneling junctions. Electrical shorting issues may be reduced by depositing electrodes without a sharp sidewall and corner but instead with a sloping or curved sidewall. Layers deposited on top of the electrode layer may then be able to adequately cover the underlying electrode layer and therefore reduce or prevent shorting. Additionally, two insulating materials may be used as the dielectric layer may reduce the possibility of incomplete coverage and the possibility of flaking. Furthermore, the electrodes may be tapered from the contact area to the junction area to provide a thin electrode where the hole is to be patterned, while the thicker contact area reduces sheet resistance. The electrode may also be patterned to be wider at the contact area and narrower at the junction area.