Indrit Myderrizi

Dogus University Electronics & Communications Engineering

Intradepartmental Seminar

June 01, 2006

An Overview of Nanotechnology and its Applications in Electronics

ContentsContents

Introduction

Survey of Nanotechnology Domains

Nano Fabrication Approaches

Nanostructures

Nano Electronics Architecture

Resources

- Nano – derived from an ancient Greek word meaning DWARF- 1 Nano = 10-9 One billionth of something- 1nm = 10-9m One billionth of a meter- 10 hydrogen atoms shoulder to shoulder

Nanotechnology:

• The art and science of manipulating and rearranging individual atoms and molecules to create useful materials, devices, and systems.

• Research and technology development at the atomic, molecular or macromolecular levels, in the length scale of approximately 1 - 100 nanometer range.

Introduction

Introduction

Survey of Nanotechnology

Domains Nanotechnology is a new way of thinking and requires

multidisciplinary activity, i.e. combinations of: biology, chemistry, computer science, engineering, material sciences, mathematics, medicine, physics

Physics

Math

Chemistry

Engineering

Biotech

Medical

Diagnostics

Clothing

Hospitality

Transportation

Medical

Communication

Electronics

Agriculture

Construction

Materials

NanoTechnology

Survey of Nanotechnology

DomainsIllustrations of industries to benefit from nanoscale manufacturing technologies are:

• Advanced materials for improved physical, chemical and biological properties. - Such materials will include catalysts, nanostructured polymers, strong and lightweight nanoparticle, nanotube or nanofiber-reinforced polymer composites and metal alloys; nanoporous polymer and metal foams; nano-grained superhard coatings for machine tools, molds, superplastically deformable nanopowder-consolidated metals and ceramics for shape forming; smart materials with embedded conductive, piezoelectric, magnetostrictive, shape memory alloy or magnetorheological elements for color, texture, conductivity control and sensory or active behavior etc.

• Electronics, information technologies and communications industries. - Examples include: molecular or nanostructured switches, amplifiers and interconnects for analog/digital data processor and storage devices, including single-electron, spin and magneto-electronics and hybrid technologies; DNA computation platforms; liquid crystal and photonic flat/flexible panel displays, photonic crystals for optical signal processing in fiber communications; nanostructured wireless transmitter/receiver microdevices for local (RF) tag identification, or satellite localization (GPS) etc.

Survey of Nanotechnology

Domains• Pharmaceutical, biochemical, food, power and environmental remediation industries. - Examples are chemical/drug screening arrays; microbial, viral and toxic gas and food sensors for warfare defense and emission control; nanostructured catalysts for reactors; nanograined films, inks, paints, fire-retardant/resistant coatings etc; nanoparticle dispersions and aerosols; consolidated nanoparticle or nanostructured proton exchange membranes for fuel cells; filtration membranes for desalination and pollution control; nanostructured cells for flexible photovoltaics, artificial photosynthesis, new types of batteries etc.

• Medical, health and safety industries. - Examples are through drug/gene bioassay arrays for genomics and proteomics research and clinical therapy; nanoparticle and nanosphere medication/gene vectors; nanostructured biomaterials for implants and prosthetics; implantable aid microdevices such as programmable medication dispensers, pacemakers, pressure/glucose detectors etc; sterile surface catheters, surgical tools, and nanoparticle agent and sensor technologies for medical imaging; nanostructured biocompatible/biodegradable scaffolds for artificial tissue engineering and regenerative medicine etc.

Survey of Nanotechnology

Domains• Aerospace, automotive and appliance industries. - high strength/weight ratio nanostructured alloy and composite materials for fuselage, body and other structural elements; highly resistive or ultra-low friction layers for thermal barrier coatings, bearing surfaces etc. in jet, internal combustion, and hydraulic/pneumatic engines and elements; nanostructured microelectromechanical systems (MEMS and NEMS) such as accelerometer and gyroscopic sensors or fuel injection and supplementary restraint fluidic actuators, reconfigurable control surfaces, etc.

• Service industries, including the users of nanomanufactured products. - nanostructured and nanofabricated product design and prototyping companies; market analysis and marketing of such products; research and development laboratories and consulting firms; intellectual property development and management services for nanomanufacturing technologies; related education at the technical school or college /university level; workforce training of professionals for nanomanufacturing industries; software development for product design, process simulation, modeling and control, continuous learning etc.

Nano Fabrication Approaches

There are two approaches to making structures on the nanoscale:

Top-down Method (present route)

Creates nanostructures out of macrostructures by breaking down matter into more basic building blocks. Frequently uses chemical or thermal methods.

Bottom-up Method (nano way)

Building complex systems by combining simple atomic level components through self assembly of atoms or molecules into nanostructures

Nano Fabrication Approaches

Lithographic Techniques

Covalent Chemistry

Supramolecular Chemistry – Aggregates

Nanoparticle Synthesis

Molecular Beam Epitaxy

SPM Probes

Nanotechnology

Up

Bottom

Ch

em

istr

y

Down

Top

Ph

ysicsE

ng

ineerin

g

Nano Fabrication Approaches

Top Down Approach - Photolithography

Silicon

“Organic”

eeee

ee

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1

2 The unirradiated “organic” is removed with an organic solvent, leaving the cross-linked insoluble network pattern.

The electron beam initiates a chemical reaction in the organic material, either

(i) leading to fragmentation to smaller molecular components, which are soluble in some solvent (positive tone resist), or

(ii) crosslinking to form an insoluble network (negative tone resist).

1

2

Nano Fabrication Approaches

3

4

A chemical etchant is employed to remove the exposed silica, and in so doing also etches the irradiated organic material, result in the pattern transfer to the silicon.

3

The pattern is then doped with appropriate materials to create an active pattern, i.e. will conduct electrons

4

Nano Fabrication Approaches

Bottom Up - Self assembly

Step 1 Isolation of atoms or molecules:

Laser source Light detector

Scanning of AFM probe

Repulsive Force

Narrow gap, dFine metal needle tip

Scanning probe

V

By using atomic force microscope: By using scanning tunneling microscope:

Step 2 Assembly of loose atoms or molecules.

Step 3 Re-bonding of atoms and molecules:Chemical synthesis

Nano Fabrication Approaches

Self Assembly Coordinated action of independent entities under distributed (i.e. non-central)

control to produce a larger structure or to achieve a desired group effect naturally occurs in biological (embryology) and chemical (supramolecular)

systems

MCM-41 diblock polymer zeolite

- Nanoporous materials – templated nanosynthesis

GA Institute of Technology

Nano Fabrication Approaches

Eventually the ‘top-down’ and ‘bottom-up’ approaches can both be combined into a single nanoelectronics manufacturing process. Such a hybrid method has the potential to lead to a more economical nano-manufacturing process.

Photolithography + Self-Assembly

Hybridization of these two approaches

T. Desai, Univ. of Illinois at Chicago

Microelectronic Component (photolithography)

O N

100 nm

35 nm

20 nm

100 nm0.1 m

10 nm

Electron Beam Lithography can create structuresof less than 10 nm.

Bottom-up is meeting Top-Down

Nano Fabrication Approaches

Nanostructures

BuckyBalls

Carbon Nanotubes

Silicon Nanowires

Quantum Dots

Nanostructures

BuckyBalls – C60

Properties Roundest and most symmetrical

molecule known to man Compressed – becomes stronger than

diamond Third major form of pure carbon Heat resistance and electrical

conductivity

C60 molecules & buckminsterfullerene Molecules made up of 60 carbon atoms arranged in a series of interlocking hexagons and pentagons C60 is actually a "truncated icosahedron", consisting of 12 pentagons and 20 hexagons.

ApplicationsPolymers/reinforcements-Compounds-High quality diamond films for electronic chips and other devices-Insulator-Batteries and fuel cell electrodes-Strengthening and hardening of metals-Sensor applications-Surface hardening coatings-Catalysts-Biological/pharmaceuticals-Copier toner-Organic chemistry building blocks-Chemical reagents

Nanostructures

Carbon Nanotubes

♦ Strong covalent bonding carbon molecules aligned in cylinder formation♦ Built by carbon vapor

Properties Thermal/electrically conductive Metallic and Semi-Conductive 4 nm width (smaller diameter

than DNA) 100x’s stronger than steel 1/6

weight can be single-walled (SWNT 1-3

nm) or multi-walled (MWNT 20-100 nm ).

ApplicationsFillers in super-strong composite materials - Wires and components in nanoelectronic devices - Tips of scanning probe microscopes and in flat panel displays and gas sensors - As macromolecules should be ideal constituents of polymers, copolymers, polymer composites, and biological structures

Nanostructures

Silicon Nanowires Properties Precise diameter control of a few nm Microns long Selectively dope length to control electrical

properties Typical diameters of nanowires 50-100nm,

although diameters as small as 3 nm are realized

♦ Grown by chemical vapor deposition

ApplicationsNanowires, tubes and particles are used in:• gates and switches in nano and microelectronics• tera-bits computer storage devices.

Nanostructures

Nanotube/Nanowire Synthesis • Chemical vapor deposition involves a gas-phase chemical reaction occurring above a solid surface, which causes the deposition onto the surface

• Principle of the synthesis is that nanoparticles of various transition metals act as catalysts to seed the growth of nanowires or nanotubes, using the feedstock gas as ingredients

• Precursors are activated• Involves thermal activation or use of combustion flame (laser ablation and arc-discharge can also be used.)

Nanostructures

Properties • Small metal or semiconductor box containing 2 electrons surrounded by an insulator with zero classical degrees of freedom moving out of the box

• Electrons repel each other so that always take two farthest positions i.e (4,2) or (1,3). One of these configurations can be treated as 1 and other as 0

• A small voltage can be applied to switch between this two configurations

• A good property of quantum dots : flow of energy from one end to other

Quantum Dot

Applications•Quantum dots can be used to implement most of logic gates

Nano Electronics Architecture

Nanotube Transistor The source/drain electrodes are typically formed by evaporating metal onto the top of the nanotube after it is deposited or grown on top of a solid substrate, such as oxidized Si. the substrate was used as the gate. However, in order to allow individual addressing of SWNT FETs on a wafer, and in order to reduce source-gate capacitance (important for high-speed), top-gates can be deposited if a suitable dielectric can be found which does not damage the SWNT.

Carbon nanotube transistors:D ~ 1 nm

Nano Electronics Architecture

Single Electron Transistor

SET Transistor • A 3-terminal device with gate, source and drain• An SET switches the source-to-drain current on and off in response to small changes in the charge on the gate amounting to a single electron• SETs are based around an island, usually of metal and containing a million or more mobile electrons• Since the Coulomb interactions among electrons block electrons from tunneling onto the island at low bias voltages "Coulomb blockade" is observed• Increasing the gate voltage for a SET to a critical value suddenly allows current to flow from source to drain, but a further increase turns off the current just as suddenly. Additional increases repeat this on/off cycle. • In order to control the number of the electrons on the island, a metal gate electrode is placed• As the gate voltage increases further the number of electrons on the island stabilizes at a value one higher than before and yet no current flows.

Nano Electronics Architecture

Logic Circuits from Carbon Nanotubes - Inverter

Carbon Nanotube Switches Core Shell Nanowires Gatedby Nanotubes or Nanowires

Diode FET

Nano Electronics Architecture

Resources

[1] Goldhaber-Gordon, D., Montemerlo, J. S., Love, J. C., Opiteck, G. J., Ellenbogen, J. C., “Overview of Nanoelectronic Devices”, MITRE Corp, The proceedings of IEEE, April 1997 [2] Burke, P.J., Yu, Z., Li, S., Rutherglen, C., " Nanotube Technology for Microwave Applications", Integrated Nanosystems Research Facility, Department of Electrical Engineering and Computer Science, University of California, Irvine[3] DeHon, A., "Array-Based Architecture for FET-Based, Nanoscale Electronics", IEEE Transactions on Nanotechnology, vol. 2, no. 1, March 2003[4] Joshi,J., "Nanotechnology. Machines, Tools & Architecture", www.tinman.cs.gsu.edu/~mpandya1/cs8530/jaimini/ [5] Wayner, D. D. M., " National Institute for Nanotechnology, Update and Status", www.thecis.ca/recordevents/wayner [6] Aourag, H., "Nanotechnology: A big issue in a small world", URMER University of Tlemcen