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In
order to maintain the current rate of improvement
in the power and capacity of electronic microprocessors
and memories, new techniques will need to be found.
One area producing significant results is that of
nanoelectronics; pairing traditional silicon chips
with the manipulation of molecules themselves, and
the technology of the tiny known as nanoscale.
The EU-funded project SANEME has developed several
techniques of great value for the manufacturing of
hybrid microchips, combining traditional silicon-based
fabrication with new nanotechnology. The main achievements
are in the creation of nanogaps - very narrow (about
5nm) spaces between the metal electrodes in an integrated
circuit - and the modelling and study of the electrical
behaviour of molecules and nanocrystals.
The
fabrication of nanogaps between electrodes is important
for the attachment of molecules to silicon chips.
The project has developed two techniques for doing
this. One, known as shadow evaporation, involves evaporating
gold atoms at an angle to the layers of gold on the
silicon wafer. The shadow cast by the edge of one
layer causes a gap of controllable size (between 2
and 6nm) to be formed.
The
second method involves the selective etching of a
gap of around 5nm between silicon electrodes on a
wafer, with the space being tailored to the size of
molecule to be added. In both manufacturing techniques
the molecules (in particular, molecules with thiol
end-groups) are then added by self-assembly to form
nanoscale electronic circuits.
The
electrical characteristics of these molecules, or
nanocrystals, and their suitability for use in nanoelectronic
devices, was then investigated as another part of
the project. By practical experiment (using scanning
tunnel spectroscopy) the properties of the molecules
were found to depend strongly on the doping of the
silicon base. Computer modelling was also used to
find out what kind of properties are needed to work
usefully in integrated circuits.
Applications
include memory chips, where the nanocrystals can be
used for refresh of DRAM or TSRAM random access memory.
Country:
United Kingdom
Information Source: Result from the EU funded IST
programme
Collaboration
Sought: Further research or development support; Information
exchange/Training; Available for consultancy
Contact Details
FORD, Chris (Mr)
University of Cambridge
SP Group
Cavendish Laboratory
Madingley Road
CB3 0HE
Cambridge
UNITED KINGDOM
Tel: +44-1223-337486
Email: cjbf@cam.ac.uk
URL: http://www.sp.phy.cam.ac.uk/SPWeb/research/saneme
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