1. Franklin Ifeanyichukwu Uba Group meeting Louisiana State University May 3, 2010

2. Outline Objective Nanotechnology Nanolithography techniques Reviews Summary Future work Acknowledgement

3. Objective To provide an overview of selected nano- pattern design techniques – Principles, merits and limitations

4. Genesis 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

5. Nano stuffs……. Prof. Norio Taniguchi (1912-1999) Tokyo State University http://www.nanoforum.org/educationtree/Images/taniguchi.jpg Prof. George M. Whitesides Harvard University ‘…collective term for a set of technologies, techniques, and processes, rather than 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).

6. Greek = English ‘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’

7. 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

8. Applications Artificial Retina

9. Nanolithography Fabrication of structures between 1 – 100 nm Properties differ from bulk forms 2-D is the basic building blocks to form functional nano-devices Evolves from Micro-fabrication http://www.nano.gov/

10. 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

11. Achievable dimensions Jie-Ren Li, Dissertation, Louisiana State University, May 2009

12. 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

13. Procedure Spin coating http://britneyspears.ac/physics/fabrication/photolithography.htm

14. Mask and Resist http://www.patrickcarlberg.dk/images/optical_lithography.jpg

15. Charged beam based 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

16. E-beam FIB FEI company, Focused ion beam technology, capabilities and applications, Tools for nanotech, (2005)

18. Contrasts FIBSEM Particle Source LMIS - Gallium LaB 6 or tungsten Type Ga + ion Electron Elementary 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 10 5 m/s 1.0 x 10 8 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

19. Other techniques

20. 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

21. Future work Design 2D – Nano-channels; FIB milling Fabricate Metal Electrodes; E-beam deposition Monitor Current blockades from single molecules

22. Acknowledgement Dr S.A Soper Dr Chantiwas Dr Matt Soper research group

23. Questions

24. ‘There is plenty of room…..’