FABRICATION PROCESSES FOR NANOMATERIALS -NANOSTRUCTURES

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Lecture 6

Process of transferring patterns to semiconductor materials in analogy to photographic process

For nano, need higher resolution than light.

X-Ray – 1-1.5nm range

Extreme UV Lithography 10-14nm range

APPLICATIONS OF NANOLITHOGRAPHY

ELECTRON PROJECTIONLITHOGRAPHY

Electron Beam Direct Write

SCALPEL (Bell Laboratories and Lucent technologies) 1995PREVAIL (IBM) 1999

Limited throughput

Electron ProjectionLithography

Huge penetrationdepth of electrons

New solutions

Direct write Projection

ELECTRON BEAM RESISTS

Somesubstrate

MANYTECHNIQUES

RESISTLIMITATIONS

Tendency of the resist to swell in the developer solution.

Electron scattering within the resist.

Broadens the diameter of the incident electron beam.Gives the resist unintended extra doses of electron exposure .

THE ELECTRON BEAM

LITHOGRAPHY

Job time estimate:t = (D*A)/I

If D = 200 C/cm2, A = 1 cm2 & I = 2nAThen t = 27 hrs 46 min

Time calculator at :http://nanolithography.gatech.edu/tcalc.php

APPLICATIONS OF ELECTRON BEAM LITHOGRAPHY

Research- Nanopatterning on Nanoparticles- Nanowires- Nanopillars- Gratings- Micro Ring Resonators- Nanofluidic Channels

Industrial / Commercial- Exposure Masks for Optical Lithography- Writing features

NANOPATTERNINGON NANOPARTICLES

Significance

- Photonic Crystals

- Quantum Dots

- Waveguides

Electron Beam Lithography

- Fine writing at moderate electron energies

- 37nm thick lines with 90nm periodicity

- 50nm diameter dots with 140nm periodiciity

(2003), Patterning of porous Silicon by Electron Beam Lithography, S. Borini, A. M. Rossi, L. Boarino, G. Amato

NANOWIRESApplications

- High-Density Electronics (Sensors, Gates in FETs)

- Molecular Electronics & Medical/Biological Applications

EBL with Electrochemical size reduction

- High-Resolution Controlled Fabrication

- Widths approaching 10nm regime

Patterning of Films of Gold Nanoclusters with Electron Beam Direct Write Lithography

- Sub 50nm wide Nanowires

- Controlled thickness at single particle level

Controlled Fabrication of Silicon Nanowires by Electron beam lithography and Electro- chemical size reduction (2005), RobertJuhasz, Niklas Elfstrom and Jan Linnros

Nanometer Scale Petterinng of Langmuir-Blodgett Films of Gold Nanoparticles by Electron Beam Lithography (2001), Martinus H.V Werts, Mathieu Lambert, Jean-Philippe Bourgoin and Mathias Brush

NANOPILLARSSignificance

- Quantum Confinement Effects- Photoconductive response in Nanopillar arrays

EBL and Reactive Ion Etching- Etched Pillars with 20nm diameter

Nanotechnology using Electron Beam Lithography, Center for Quantum Devices

GRATINGSApplications

- Distributed Feedback Lasers- Vertical Cavity Surface Emitting Lasers

Continuous Path Control Writing using EBL- Avoids stitching errors

Nanotechnology using Electron Beam Lithography, Center for Quantum Devices

Significance- Laboratory on a chip

- Single Molecule Detection

Electron Beam Lithography- Single step planar process

- Tubes with inner dimension of 80nm

(2005) A single-step process for making nanofluidic channels using electron beam lithography, J. L. Pearson and D. R. S.

Cumming

NANOFLUIDIC CHANNELS

PDMS* Microfluidics Fabrication

*polydimethylsiloxane

EXTREME ULTRAVIOLET LITHOGRAPHY

Small wavelengthBetter resolution

No lenses: mirrors

Laser plasma sources

10 nm

nanoporous template

Nanomagnets in a Polymer Mask

1x1012 magnets/in2

Data Storage......and More

Metal Nanorings

NANOLITHOGRAPHY

Advantages

• High resolution• Precise manipulation of

single molecules• Inexpensive compared to

similar high resolution techniques

• Imaging capabilities allow real-time manipulation

• Can be performed in ambient conditions (including fluids)

Disadvantages

• Currently a serial process• Scanner nonlinearities • Can be slow

Iron atoms where arranged on a copper surface to make the kanji

character for "atom"

Carbon Monoxide Man consistingof carbon monoxide molecules

on a platinum surface

STM

SURFACE MANIPULATION WITH AFM•Surface manipulation of colloidal gold on

mica•Data storage •Sensors•Single electron transistors

J. Vacuum Sc. & Tech. B, Vol. 15, No. 4, pp. 1577-1580, 1997

•Manipulation of Nanotubes•Single molecule logic circuit

Science, Vol. 292, Issue 5517, April 27, 2001

DIP-PENNANOLITHOGRAPHY

AFM tip “inked” with molecule of interestTransport occurs through meniscus formed between tip and substrate

EXAMPLES OF DPN INKS INCLUDE THIOLS, ANTIBODIES, POLYMERS

Electroluminescentpolymers

Tagged antibodies

Human Hair (80 m width)

Thiol ‘Ink’on gold(Friction Image)

Noy et al., Nano Letters (2002)

Chemical ‘Ink’on glass(Confocal Images)

MILLING

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ION BEAM

320 x 90 nm

100nm to 1 m

TEM images of a FIB machined single crystal molybdenum pillar,

ANODISING

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ANODIZED ALUMINUM OXIDE TEMPLATES

e.g., • Keller, et al., J. Electrochem. Soc. 100, 411 (1953)• Masuda & Fukuda, Science 268, 1466 (1995)

Masuda, et al.

PROPOSED AAO GROWTH MECHANISM

E

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TITANIUM OXIDE38

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MANY OF THE PROCESSES JUST MENTIONED

Tedious and time consumingThere must be a more efficient way

PROCESSING RATE VS. LITHOGRAPHY AND ITS BEST

RESOLUTION

PhotolithographyE-beam lithography

AFM lithography

STM lithography

-25

Hours

-30

00

Years

-3 billion years

-30

Years

-1/10

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