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The semiconductor industry
has seen a remarkable miniaturization trend, driven by many
scientific and technological innovations. But if this trend is
to continue, and provide ever faster and cheaper computers, the
size of microelectronic circuit components will soon need to
reach the scale of atoms or molecules—a goal that will require
conceptually new device structures. The field of molecular
electronics seeks to use individual molecules to perform
functions in electronic circuitry now performed by semiconductor
devices. Individual molecules are hundreds of times smaller than
the smallest features conceivably attainable by semiconductor
technology. Electronic devices constructed from molecules will
be hundreds of times smaller than their semiconductor-based
counterparts. Moreover, individual molecules are easily made
exactly the same by the billions and trillions. The dramatic
reductions in size, and the sheer enormity of numbers in
manufacture, are the principle benefits promised by the field of
molecular electronics.
Presently, our
manufacturers manipulate millions and billions of atoms at a
time using conventional technologies. They manipulate these
atoms by pounding, chipping and other large scale mechanical
deformation. They cook up pure silicon and then etch patterns on
its surface. All these techniques depend on large scale
manipulation of atoms. Manipulating atoms today is like trying
to build houses out of Lego blocks using boxing gloves. You can
push the Lego blocks together, but it's extremely difficult to
make them snap together. In the future, molecular nanotechnology
will allow us to take off the gloves and manipulate atoms
directly. This will allow very complete control over the
placement of individual atoms.
Often, nanotechnology is
referred to as "bottom-up" manufacturing. It aims to start with
the smallest possible building materials, atoms, and use them to
create a desired product. Working with individual atoms allows
the atom-by-atom design of structures. In most chemical
reactions, unwanted byproducts are an inevitable consequence of
the lack of control over the bonding reactions. With
nanotechnology, unwanted byproducts can be essentially
eliminated.
Nanotechnology should
allow us to get essentially every atom in the right place, make
almost any structure consistent with the laws of physics and
chemistry that we can specify in atomic detail, and have
manufacturing costs not greatly exceeding the cost of the
required raw materials and energy.
Before nanotechnology can
become anything other than a very impressive computer
simulation, nanotechnologists must invent an assembler, a
few-atoms-large nanomachine that will custom-build matter.
Engineers at Cornell and Stanford, as well as at
Zyvex (the self-described "first molecular nanotechnology
development company") are working to create such assemblers
right now. But the obstacles are daunting. Unlike building with
traditional materials that stay where you put them, atoms and
molecules are volatile and will rearrange themselves
Current
and Emerging Electronic And Computer Technologies
constantly
to maintain stability. How far are we from having an assembler?
Estimates vary. From 5 to 10 years, according to Zyvex, or from
8 to 15 years, according to the research community. After that,
it could be decades before we'll be able to manufacture finished
consumer goods.
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