Download - Scanning Probe Lithography
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Yongshik ParkFebruary 13th, 2008EE C235/NSE C203
Scanning Probe Lithography
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OutlineScanned Probe Oxidation
Generating an Polymer “Resist” Layer using
Scanning Probe Lithography
High-Field Scanning Probe Lithography in
Hexadecane
Cons and Pros
Conclusions
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Scanned Probe Oxidation
Began at NIST in 1989Electrical bias between a conducting tip
and a substrate induces a highly localized enhanced oxidation.
Typical line width: 10~20nm
J. A. Dagata, Science, Vol. 270, 1995, pp1625-1626
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Scanned Probe Oxidation- Applications
Fabrication of Si nanowire Fabrication of single tunneling transistor(SET)
J. A. Dagata, Science, Vol. 270, 1995, pp1625-1626
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Generating an Etch Resistant “Resist” Layer from Common Solvents
An organic electrolyte replaces water to generate an organic resist.
Scan rate: 10um~20um
DC Bias
Fluid Cell
Solvent vapor
I. Suez, S. Backer, J. Frechet, Nano Letter, Vol. 5, No. 2, 2005, pp321-324
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Generating an Etch Resistant “Resist” Layer from Common Solvents
The height of n-octane: 2.5nm (40% higher than the case of water)
After etching, the height of step: 8.5nm
After generating n-octane patterns After etching
I. Suez, S. Backer, J. Frechet, Nano Letter, Vol. 5, No. 2, 2005, pp321-324
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High-Field Scanning Probe Lithography in Hexadecane - Hydrophobocity
Surface hydrophobocity
determines the deposited material.
Hydrophilic SiO2
Hydrophobic n-octane
Oxidation of the silicon surface
occurs in the meniscus formed by
the water dissolved in the fluid,
with minimal effects on the
reaction from the surrounding
solvents
I. Suez, M. Rolandi, S. Backer, A. Scholl, J. Frechet, Advanced Materials, Vol. 19, 2007, pp3570-3573
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High-Field Scanning Probe Lithography in Hexadecane - Hydrophobocity
Etching makes trenches on hydrophilic surface and tall posts on hydrophobic surface.
On Hydrophilic surface On Hydrophobic surface
After deposition(black)
After etching(red)
I. Suez, M. Rolandi, S. Backer, A. Scholl, J. Frechet, Advanced Materials, Vol. 19, 2007, pp3570-3573
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High-Field Scanning Probe Lithography in Hexadecane – PEEM analysis
Although there are only small differences in features of the local spectra, carbon content information was obtained1st and 2nd peak: C=C double bond3rd peak: hybridized carbon atoms
I. Suez, M. Rolandi, S. Backer, A. Scholl, J. Frechet, Advanced Materials, Vol. 19, 2007, pp3570-3573
PEEM analysisAFM image Carbon signal PEEM
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Cons and ProsCons
Can make nano patterns without optical apparatus
Can control deposited material by hydrophobocity of the surface
Can make arbitrary patterns by controlling the trajectory of AFM tip
ProsLow throughput: serial scan and low speed
Multiple tipsSmall scan area
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ConclusionsScanning probe oxidation can make
nanowire, SET, etc.By using an organic solvent, the organic
material can be deposited on the surface.The hydrophobocity determines the
deposited materialHydrophilic surface SiO2Hydrophobic surface hydrocarbon
By PEEM analysis, the deposited material on the hydrophobic surface has carbon components.