Chemically-sensitive field effect transistors, systems, and methods for manufacturing and using the same
Inventors
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Assignees
MemberParagrafParagrafParagraf specializes in the development and manufacture of wafer-scale, silicon-compatible graphene electronic devices and sensors. Utilizing a proprietary process for direct, contamination-free graphene synthesis, the company delivers scalable solutions for magnetic field sensing, molecular and biosensing, and advanced electronics integration. These technologies address challenges in cryogenics, quantum computing, automotive, aerospace, environmental monitoring, and healthcare. With a focus on large-scale integration of 2D materials, Paragraf advances next-generation sensors and components for demanding and extreme environments.
Paragraf specializes in the development and manufacture of wafer-scale, silicon-compatible graphene electronic devices and sensors. Utilizing a proprietary process for direct, contamination-free graphene synthesis, the company delivers scalable solutions for magnetic field sensing, molecular and biosensing, and advanced electronics integration. These technologies address challenges in cryogenics, quantum computing, automotive, aerospace, environmental monitoring, and healthcare. With a focus on large-scale integration of 2D materials, Paragraf advances next-generation sensors and components for demanding and extreme environments.
Publication Number
US-10429381-B2
Publication Date
2019-10-01
Expiration Date
Abstract
This invention concerns Chemically-sensitive Field Effect Transistors (ChemFETs) that are preferably fabricated using semiconductor fabrication methods on a semiconductor wafer, and in preferred embodiments, on top of an integrated circuit structure made using semiconductor fabrication methods. The instant ChemFETs typically comprise a conductive source, a conductive drain, and a channel composed of a one-dimensional (1D) or two-dimensional (2D) transistor nanomaterial, which channel extends from the source to the drain and is fabricated using semiconductor fabrication techniques on top of a wafer. The ChemFET also includes a gate, often the gate voltage is provided through a fluid or solution proximate the ChemFET. Such ChemFETs, preferably configured in independently addressable arrays, may be employed to detect a presence and/or concentration changes of various analyte types in chemical and/or biological samples, including nucleic acid hybridization and/or sequencing reactions.
Core Innovation
The invention concerns Chemically-sensitive Field Effect Transistors (ChemFETs) that preferably comprise a conductive source, a conductive drain, and a channel composed of a one-dimensional (1D) or two-dimensional (2D) transistor nanomaterial extending from the source to the drain and fabricated using semiconductor fabrication techniques on top of a wafer or over an integrated circuit structure. The ChemFETs include a gate, often with the gate voltage provided through a fluid or solution proximate the ChemFET, and in some embodiments include analyte or reaction-sensitive insulation layers and passivation wells associated with the channel.
The patent identifies shortcomings of conventional ISFET/MOSFET biosensors including lack of sensor sensitivity, poor signal-to-noise characteristics as transistor geometries scale down, and deleterious effects from increased interconnect wiring and smaller transistor sizes; what is needed is a FET device with channels that have high surface area to volume ratio and high carrier mobility to allow increased sensor sensitivity and accuracy. The disclosure is directed to ChemFET devices, systems and methods that employ 1D nanomaterials (e.g., CNTs, Si NWs), 2D nanomaterials (e.g., graphene, MoS2), and 3D structures, configured as solution-gated, dual-gated, and gate-all-around (GAA) sensors configured in arrays for chemical and biological analyses including nucleic acid hybridization and sequencing.
The disclosure further provides methods and structures for integrating such ChemFETs onto semiconductor IC wafers, including formation of wells or passivation openings, use of etch stop layers, backgates or local backgates, and techniques for growing and transferring 2D nanomaterials to ROIC wafers; [procedural detail omitted for safety]. These devices and arrays are described for use with associated ROICs, processors, and fluidics components to detect changes in conductance or shifts in I−V or Id−Vgs curves that indicate chemical reactions, analyte presence, or biological activity.
Claims Coverage
The independent claims disclose three principal inventive features relating to multi-layered ChemFET structures that incorporate graphene channel layers in combination with insulating layers, embedded electrodes, and gate structures.
Multi-layered structure with embedded electrodes and overlapping gate
A chemically-sensitive field effect transistor comprising a substrate layer, first and second insulating layers, a source electrode and a drain electrode with surfaces at least partially disposed within the first insulating layer, a graphene layer positioned between the first and second insulating layers contacting the exterior portion of the electrodes and extending to form a channel, and one or more surface structures forming a gate that overlaps at least a portion of the source and drain electrodes and is at least partially positioned in the second insulating layer.
Alternating electrode and graphene channel arrangement with overlying gate
A multi-layered ChemFET comprising first and second insulating layers, a first pair of source and drain electrodes coupled by a first gate structure, a second pair of source and drain electrodes with a graphene layer positioned between the first and second insulating layers contacting the top surfaces of the second pair of electrodes to form a channel, and one or more second structures forming a second gate that overlaps portions of the second source and drain electrodes.
Paired electrode configuration with graphene-formed channel
A ChemFET having first and second pairs of source and drain electrodes at least partially positioned in a first insulating layer, where the first pair is coupled by a first gate and the second pair is coupled together by a channel formed of a graphene layer that contacts a surface of each electrode of the second pair.
The independent claims center on multi-layer ChemFET devices in which a graphene channel is positioned between insulating layers and electrically contacts source/drain electrodes embedded in an insulating layer, combined with gate or surface structures that overlap source and drain regions to form well-defined solution-gated, dual-gated, or GAA sensing configurations.
Stated Advantages
Increased sensor sensitivity and accuracy through use of 1D/2D/3D nanomaterial channels with high surface area to volume ratio and high carrier mobility.
Reduced noise and improved signal-to-noise characteristics compared to traditional semiconductor FET-based ISFETs.
Smaller sensor sizes and dense, independently addressable arrays compatible with semiconductor IC fabrication (CMOS) enabling mass production, lower cost, and portability.
Capability for label-free, direct electronic detection of chemical and biological reactions, including nucleic acid hybridization and sequencing, with on-chip readout and processing.
Enhanced gate control (dual gate and gate-all-around structures) to further improve sensitivity, including potential sensitivity beyond the Nernst limit.
Documented Applications
Detection and sequencing of nucleic acids, including nucleic acid hybridization and Next Generation Sequencing (NGS) reactions.
Genetic diagnostics, genome identification, genotyping, SNP genotyping, and related clinical/genomic analyses (e.g., whole genome analysis, exome analysis, microbial/microbiome analysis, cancer analysis, NIPT analysis, cfDNA, blood/plasma/serum analysis).
Analyte detection and identification, including sensing of ion concentration (pH) changes and other analyte concentration changes in chemical and biological samples.
Biosensing formats including independently addressable sensor arrays, wells or chambers for micro- or nano-bead based assays, antibody-antigen detection, cell activity monitoring, and microbead-associated template sequencing.
Integration with ROICs and computing components for on-chip signal generation, Id−Vgs curve comparison, base calling, mapping, alignment, and variant calling for sequencing data processing.
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