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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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