Franklin Ifeanyichukwu UbaGroup meeting

Louisiana State UniversityMay 3, 2010

Outline• Objective• Nanotechnology• Nanolithography techniques• Reviews• Summary• Future work• Acknowledgement

Objective

To provide an overview of selected nano-pattern design techniques – Principles,

merits and limitations

Genesis• ‘There is plenty of rooms at the bottom’ ……..APS lecture Dec 29, 1959

Richard Phillips Feynman (1918 – 1988)Physics Nobel laureate (1965)

http://www.acceleratingfuture.com/michael/blog/

“…Why can’t we write the entire 24 volumes of the encyclopedia Britannica on the head of a pin ?..”

“I don’t know how to do this on a small scale at a practical level,………”

“……..by little, I mean little.”

Chris Toumey, Apostolic Succession, Engineering & science no. 1 / 2. 2005

Nano stuffs…….Prof. Norio Taniguchi (1912-1999)Tokyo State University

http://www.nanoforum.org/educationtree/Images/taniguchi.jpg

Prof. George M. WhitesidesHarvard University

‘…collective term for a set of technologies, techniques, and processes, ratherthan a specific science or engineering discipline….’

Coined the word ‘Nanotechnology’.

Nanotechnology... ‘a word not a field’.

Harvard’s George Whitesides on Nanotechnology: ‘Science Watch,2002 (July/August).

Greek Nano =

English

Dwarf‘world of the very small things’

http://www.eglobe1.com/word/wpcontent/uploads/2008/05/strongest-dwarf.jpg

Scientific discipline attach ‘nano-label’ to become part of nanoscience and nanotech.

‘a Billionth of a meter……10-9 m’

Areas in nanotechnology

•Nanoelectronics Nanorobotics

•Nanomechanics

http://compmech.cveg.uark.edu/airplane.gif

•Nanomedicine

• Nanomagnetics

• Nanophotonics

• Nanobiology

• Nanomaterials

http://www.cl.cam.ac.uk/~sps32/proj_pict/sega_01.jpghttp://www.edinformatics.com/nanotechnology/400px-MolecularImagingTherapy.jpg

Applications

Plasma Displays

Quantum Computers

Solar CellsFuel Cells

Nano Tubes

Aerogel

Nano Particles

Artificial RetinaTargeted Drug Delivery

Tissue Regeneration

Nanolithography• Fabrication of structures between 1 – 100 nm

• Properties differ from bulk forms

• 1-D - Thin films (a few atoms thick), Nano-slits

• 2-D - Planar transistors, magnetic or photonic elements,

Nano-channels

• 3-D - Nano-particles, Carbon nano-tubes, Nano-wires

• 2-D is the basic building blocks to form functional nano-devices

• Evolves from Micro-fabricationhttp://www.nano.gov/

Methods• Photon-Based Lithography

• Charged beam based lithography• Electron beam lithography• Ion-Beam lithography • Conventional pattern transfer technologies• Deposition• Reactive-ion etching• Un-conventional nanofabrication• Scanning probes• Replication of stamps

• Indirect fabrication

• Self assembly

Achievable dimensions

Jie-Ren Li, Dissertation, Louisiana State University, May 2009

Photon-based lithography• Fabrication with photons• Deep Ultra violet• Extreme Ultraviolet• X-rays

• Photomask (reticle)• Photoresist

Attwood, D., Soft X-Rays and Extreme Ultraviolet Radiation: Principles and applications. 2000, Cambridge University Press

Procedure

Spin coating

http://britneyspears.ac/physics/fabrication/photolithography.htm

Contact Proximity Projection

Mask and Resist

http://www.patrickcarlberg.dk/images/optical_lithography.jpg

Charged beam based • Electron beam (e-beam) or Ion Beam nanofabrication

• High energy direct or indirect transfer

• E-beam evolved from SEM – 1960s

• FIB; Liquid Metal Ion Source (LMIS) – 1980s

Z. Cui, Nanofabrication, DOI: 10.1007/978-0-387-75577-9_3

Conditions for High resolution• High electron/ion energy

• Small scanning field

• Low beam current

• Low-sensitivity resist

•Thin resist layer

• Optimized resist process

• Low pattern density

• Light and conductive substrate material

• Stable environment

E-beam FIB

FEI company, Focused ion beam technology, capabilities and applications, Tools for nanotech, (2005)

ContrastsFIB SEM

Particle Source LMIS - Gallium LaB6 or tungstenType Ga+ ion ElectronElementary charge

+ 1 - 1

Particle size 0.2 nm 0.00001 nm

Mass 1.2 x 10-25 kg 9.1 x 10-31 kg

Velocity at 30kV

2.8 x 105 m/s 1.0 x 108 m/s

Momentum 3.4 x 10-20 kgm/s 9.1 x 10-23 kgm/s

FEI Company, Focused ion beam technology, capabilities and applications, Tools for nanotech, 2005

Other techniques

Summary• Optical lithography – high throughput technique Diffraction limit Labor intensive• Charged particle lith. – Effective milling and deposition Low throughput and expensive High level of expertise Dopant - FIB• Other techniques – Achieve smaller dimensions Expensive

Future work

• Design 2D – Nano-channels; FIB milling

• Fabricate Metal Electrodes; E-beam deposition

• Monitor Current blockades from single molecules

Acknowledgement

• Dr S.A Soper

• Dr Chantiwas

• Dr Matt

• Soper research group

Questions

‘There is plenty of room…..’