Integration of Nano Transistor Food Biosensors

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October 21, 2009

Gary K. Maki*, Wusi C. Maki* and Nirankar Mishra

CAMBR, University of Idaho, Post Falls, ID

Integration of Nano Transistor Food Biosensors

BC Food Protection Association Workshop Supported by USDA

*Now with Integrated Molecular Sensors

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Integration of MicroelectronicsCAMBR/NASA Custom Processors

• Reed Solomon Coder– Programmable error

correction, message length• Lossless Data Compressor

(USES)• Low Density Parity Check

Encoder– Landsat Data Continuity

Mission• High Performance Data

Compression– MMS mission

• New correlator work underway– GeoStar IIP

Delivered November 2008

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GeoStar System• The GeoStar system enables astronomers to advance science

with a space based imager which will correlate data from 588 separate antennas.

• This requires a custom processor board capable of 442,368,000,000,000 correlations per second while using less than 120W for the correlations.

• Equivalent to 17,332 Quad Intel Processors consuming 346,600 watts (not counting memory)

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Nano Technology Promise

• Increased Sensitivity– Electronic device size approximate size of

detection molecule• Nano transistors on order of 50 nm capable of

manufacture in modern semiconductor foundries– IBM, Intel, TSMC markets 45 nm electronics– With proper integration, possible to mass produce

sensitive detection electronics• $20 detectors with integrated microprocessors with

USB interfaces

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Au AuNano FET

Al Al

VSSAmplifier ComputerDigitizer

Off Chip Communications

Silicon Substrate

Self-assembled monolayerCapture Molecule

Target Molecule

Integration of Electronic Biosensor

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Detector Sensor

Electronic Amplifier

Micro processor

Communication Link

Cell Phone Internet Satellite Computers

National Data Base

Pathogen Biomarker Capture &

Amplification

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Technologies/Expertise

• Molecular Biology/Biochemistry• Nano Technology• Semiconductor Fabrication• Surface Chemistry• Electronics

– Digital Design– Analog Design– Special purpose computers

• How to integrate people/technologies

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Work Together• Multiple disciplinary

– Speak the same language• Substrate

– Understand basic concepts• Cross Knowledge borders

– Ph.D’s are experts in narrow fields– Ph.D’s do not like to show ignorance Electronic Engineering Molecular Biology

Chemistry

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Food Safety Detection Targets

• Toxins– SEB SEC (Staph)– Stx1, Stx2 (E. coli)

• Bacteria signature DNA– 16S rRNA gene

• Bacteria signature RNA– 16S rRNA

• E. coli O157:H7 – Specific phage KH1

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Virus

BacteriumDNA

Protein

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Nano-FET Nano-FET

Nano-FETNano-FET

Ideal Detection Real Detection

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Au AuNano FET

Al Al

VSSAmplifier ComputerDigitizer

Off Chip Communications

Silicon Substrate

Self-assembled monolayerCapture Molecule

Target Molecule

Established Bio-Recognition Methods

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Au AuNano FET

Al Al

VSSAmplifier ComputerDigitizer

Off Chip Communications

Silicon Substrate

Self-assembled monolayerCapture Molecule

Target Molecule

Established Microelectronic Technology

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Bio-MolecularRecognition

Signal Generation

Electronic Signal

Amplification

Digitalization

Challenges In Signal generation and Interface

The interface of Nano- and Micro-electronics

The interface of Bio-Molecules and Nano-sensing

surface

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Interface QuestionsCharge must be generated from target recognition

Charge must be brought to the sensing surfaceInsulator layer on the nanowire must be as thin as possible

Nanowire must be affected by very small E-fieldWhich generates a detectable electronic signal

Electronic signal is amplified and digitalized

How to generate charge? What kind of charge? How much?

How to attach the charge to the surface? How to make ultra-thin insulator layer?

How to integrate nano-/micro-electronics? Temperature and packaging problems

Signal level: magnitude only? Phase? Electronic amplify?

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Challenges in Charge Generation

• Not all molecules are alike– Charge quantity variable

• Example

– Charge sense variation• DNA negative charge• Poly-lysine positive charge• Steroid hormone charge neutral

• Transistor Impacts– Transistor variation with different targets– Transistor surface modification

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Solution for Charge Generation

• Keep engineer’s life simple– Known amount of charge– Known charge sense– No transistor surface modification

• Ease design pain• Enable mass production

• Engineers have to design only one thing and produce billions of identical copies

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Universal Signal Molecule

Target RecognitionSignal Molecule

Generation

Same SignalMolecule

- known charge

Target InvariantElectronics

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Universal Nano-FET Biosensor

PNA

Signal Molecule

Antigen

Antibody

Universal Detection Model

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Transistor Design

• Device which detects molecular charge• Specifications

– Wafer– Doping level– Nanowire Length– Contact material– Insulator layer– Sensing area

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Signal Data

• Nano Transistor– nano amp current

• Noise Problems– External noise

• Light, 60 Hz, electrical ground movement

• Long wires from nano FET to instrument

• No alligator clips– Internal noise

• Electrical grounding, cross talk, leakage

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Transistor Layout

Au Pad Au PadDoped Silicon

Top View

Silicon Wafer

Insulation LayerDoped Silicon

Au PadPNAAu Pad

Side View

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Areas of Concern

Silicon Wafer

Insulation Layer

Au PadPNAAu Pad

Side View

Contact

Doped Silicon

High reliability needed

Example 0.01% Modern VLSI chip with 100M Xsters4 contracts per transistor10,000 Xsters non-functional

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Areas of Concern

Silicon Wafer

Insulation Layer

Au PadPNAAu Pad

Thickness

Doped Silicon

Nano FET Surface ThicknessSmall for good E-FieldThick for insulation

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Au Pad Au PadDoped silicon

Au Pad Au PadDoped silicon

Au Pad Au PadDoped silicon

Au Pad Au PadDoped silicon

Au Pad Au PadDoped silicon

Au Pad Au PadDoped silicon

University of Idaho - CAMBR 25

Au Pad Au PadDoped silicon

Digital Electronics

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Au Pad Au PadDoped silicon

Au Pad Au PadDoped silicon

Au Pad Au PadDoped silicon

Au Pad Au PadDoped silicon

Au Pad Au PadDoped silicon

Au Pad Au PadDoped silicon

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Au Pad Au PadDoped silicon

Digital ElectronicsAnalog Signal to DigitalWith multiple sensors, quality control routineData Analysis to map Target IdentifyIntelligent I/O InterfaceInternet Communication

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Au Pad Au PadDoped silicon

Au Pad Au PadDoped silicon

Au Pad Au PadDoped silicon

Au Pad Au PadDoped silicon

Au Pad Au PadDoped silicon

Au Pad Au PadDoped silicon

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Au Pad Au PadDoped silicon

Digital Electronic ProblemsProcessing Order1. Create Digital Circuits (20 layers)2. Place Gold pads3. Place doped silicon on gold pads

• High Temperature Process• Nano packaging solution ?

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Integration of Nano- and Microelectronics

Microelectronics

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Hybrid Packaging Approach

•Short wire interface•Common ground•Noise reduction elements•Single package

Nano-device Micro-electronics

Hybrid Package

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Conclusion

• Systems Level Problem• Various Technology experts needed• Integrated team is needed• Resource costs are High

– nano foundry (already exists)– Digital/Analog Design Tools

• Commercial costs > $1M/year• Engineering experts needed• Commercial fabrication > $200K/run

– Biomolecular laboratory