Nanotechnology Nanofabrication of Functional Materials Marin Alexe Max Planck Institute of Microstructure Physics, Halle - Germany
Contents Part I History and background to nanotechnology Nanoworld Nanoelectronics Nanomaterials Nanofabrication Part II Nanofabrication of functional materials Scaling down of ferroelectric materials Nanoferroelectrics?
Contents Part I Nano-size Nano -dreams Nanoelectonics History Backgrounds to nanotechnology
nano=10-9 m From macro toward nano via meso macroscopic? quantum 1 m 1 mm 1 µm 1 nm 1 pm nano
Nano - dreams NANOBOTS
Nano - dreams NANOBOTS
Nanoelectronics short history
History 1947: Bardeen, Brattain & Shockely invented the transistor, foundation of the IC industry. 1952: SONY introduced the first transistor-based radio. 1958: Kilby invented integrated circuits (ICs). 1965: Moore s law. 1968: Noyce and Moore founded Intel. 1970: Intel introduced 1 K DRAM.
History 1971: Intel announced 4-bit 4004 microprocessors (2250 transistors). 1976/81: Apple II/IBM PC. 1985: Intel began focusing on microprocessor products. 1996: Samsung introduced 1G DRAM. 1998: IBM announces1ghz experimental microprocessor. 2001: Intel P4 has > 42 million transistors.
Moor s Law Logic capacity doubles per IC at regular intervals (1965). Logic capacity doubles per IC every 18 months (1975).
Need of nanotechnology Human factors may limit design more than technology. Need of a disruptive technology
Nanotechnology matter The cost is dictated by the processing (ex. The main cost in microelectronics is set by lithography + related tools) Nanotechnology should be in principle an inexpensive technology information function process
Nanomaterials
Nanomaterials Nanomaterials: Better nanoscale design Defect tolerable designed functions Cheaper better processing Self-repairing self-assembly Example: human skin
Backgrounds to nanotechnology Transmission electron microscopy Scanning electron microscopy Scanning probe microscopy Nano manipulators Atom manipulation Self-assembly Molecular assembly
Backgrounds to nanotechnology Transmission electron microscopy Ruska and Knoll 1932
Backgrounds to nanotechnology Transmission electron microscopy imaging electron diffraction
Backgrounds to nanotechnology Imaging in TEM mass-contrast Diffraction Z-contrast
Backgrounds to nanotechnology Imaging in TEM Bright field image Latex particles on carbon support film Selective mass contrast Reverse
Backgrounds to nanotechnology Imaging in TEM Z-contrast image McKee et al. Phys. Rev. Lett. 81 3017
Backgrounds to nanotechnology Scanning electron microscopy D. R. S. Cumming, et al. Microelectronic Engineering 30 (1996), 423-425 Hitachi
Nanofabrication Transformation of the investigation tools in fabrication tools
Nanofabrication Handbook of Nanostructured Materials and Nanotechnology, ed. N. S. Nalwa,, Academic Press, 2000
Nanofabrication Photo -lithography Photolithography X-ray lithography E-beam lithography Scanning Probe Methods Soft lithography Bottom-Up
Photolithography The art of making complicated and very precise pictures Photolithography (optical, UV, EUV) KrF λ =248nm ArF λ =193nm F2 λ =157nm Projection lithography
Photolithography Advantages Parallel processing High throughput Environmental technique (no vacuum) Disadvantages Resolution limit ~ 50 nm High cost tools
Electron beam lithography (EBL) Direct writing and Projection Exposure source: electron beam λ = h 2mV 1 + ce ev 2mc c 2 SEM EBL At acceleration voltage Vc =120kV, λ =0.0336Å Utilizes an electron column to generate focused e-beam
Electron beam lithography Advantages Better resolution Direct writing, no mask needed Arbitrary size, shape, order Disadvantages Serial process slow, small area D. R. S. Cumming, S. Thoms, J. M. R. Weaver and S. P. Beaumont, Microelectronic Engineering 30 (1996), 423-425
Electron beam lithography SCALPEL (SCattering with Angular Limitation Projection Electron-beam Lithography) Lucent
Scanning probe methods Plastic deformation of polymers (plowing) Tip-induced surface reactions (ex. Si oxidation) Dip-pen lithography Moving atoms and molecules by STM or AFM others
Scanning probe methods Tip-induced reactions Silicon line 3.5nm width fabricated across a monatomic terrace on a silicon (111) surface. The line is fabricated by selective dissociation of silane gas by the tip of the STM. Univ. of Cambridge
Scanning probe methods Dip-pen lithography Chad Mirkin, Northwestern University
Scanning probe methods Moving atoms and molecules by STM or AFM
Scanning probe methods Gold on mica University of Southern California Plucking off and losing atoms on Si (NASA)
Scanning probe methods 48 iron atoms on Cu (111) IBM Xe on Ni(110) IBM
Nanomanipulators
Soft lithography, µ contact & µ molding
Soft lithography nano-imprint S. Chou, Princeton Mold Imprinted PMMA
Bottom-up methods
Bottom-up Bottom-up methods start from molecules (atoms) to build up (functional) nanosize structures Advantages Cheap Dimensions ~10 nm Simple Low cost Disadvantages Low reproducibility No interconnection Successful examples Carbon nanotubes Quantum dots
Bottom-up
Bottom-up
Bottom-up Density of electronic states as a function of structure size.
Bottom-up
Bottom-up Perfect bottom-up example: cell division Self-assembly & self-replicating Cell replication needs thee classes of molecules: DNA RNA proteins
Molecular assembly 23 1mol 10 links@10ns 10 14 s Molecular assembler Molecular gear, NASA Eric Drexler, Engine of Creation
Imagination is more important than knowledge. Albert Einstein