franklin ifeanyichukwu uba group meeting louisiana state university may 3, 2010
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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…..’
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