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starship-design: Fwd: Atomic scale memory
In a message dated 9/9/02 9:51:17 AM, KStarks.Apollo@SIKORSKY.COM writes:
>
>
>
>
>http://www.news.wisc.edu/releases/view.html?id=7774
>
>
>
>FOR IMMEDIATE RELEASE
>
> 9/3/02
>
> CONTACT: Franz J. Himpsel (608) 263-5590, (608)
>
>877-2000 fhimpsel@facstaff.wisc.edu
>
>
>
> NOTE TO PHOTO EDITORS: To download a high-resolution
>
>image to accompany this story,
>
> visit: http://www.news.wisc.edu/newsphotos/atomic.html
>
>
>
>
> SCIENTISTS DEVELOP ATOMIC-SCALE MEMORY
>
>
>
> MADISON - In 1959, physics icon Richard Feynman, in
>a
>
>characteristic
>
> back-of-the-envelope calculation, predicted that all
>
>the words written in the history of the
>
> world could be contained in a cube of material one
>
>two-hundredths of an inch wide -
>
> provided those words were written with atoms.
>
>
>
> Now, a little more than 40 years after Feynman's
>
>prescient estimate, scientists at the
>
> University of Wisconsin-Madison have created an
>
>atomic-scale memory using atoms of
>
> silicon in place of the 1s and 0s that computers use
>to
>
>store data.
>
>
>
> The feat, reported in the journal Nanotechnology,
>
>represents a first crude step toward a
>
> practical atomic-scale memory where atoms would
>
>represent the bits of information that
>
> make up the words, pictures and codes read by
>
>computers.
>
>
>
> "This is proof of concept of what Feynman was saying
>40
>
>years ago," says Franz Himpsel,
>
> a UW-Madison professor of physics and the senior author
>
>of the Nanotechnology paper.
>
>
>
> Although the memory created by Himpsel and his
>
>colleagues is in two dimensions rather
>
> than the three-dimensional cube envisioned by Feynman,
>
>it provides a storage density a
>
> million times greater than a CD-ROM, today's
>
>conventional means of storing data.
>
>
>
> The atom, says Himpsel, represents the "hard wall"
>of
>
>technological miniaturization. "We
>
> seem to be at a natural limit."
>
>
>
> Although divisible, the atom is a fundamental unit
>of
>
>nature. They are the smallest
>
> particles of an element and a single grain of sand,
>for
>
>example, can contain 10 million
>
> billion atoms.
>
>
>
> The new memory was constructed on a silicon surface
>
>that automatically forms furrows
>
> within which rows of silicon atoms are aligned and
>rest
>
>like tennis balls in a gutter. By
>
> lifting out single silicon atoms with the tip of a
>
>scanning tunneling microscope, the
>
> Wisconsin team created gaps that represent the 0s
>of
>
>data storage while atoms left in
>
> place represent the1s.
>
>
>
> Like conventional memory, the atomic-scale device
>can
>
>be initialized, formatted, written
>
> and read at room temperature.
>
>
>
> By manipulating individual atoms at room temperature
>to
>
>create memory, Himpsel and his
>
> colleagues are treading a middle ground between atom
>
>manipulation at very low
>
> temperatures and conventional data storage, which
>
>operates at room temperature but
>
> uses millions of atoms per bit. It is far easier to
>
>manipulate atoms one at a time and
>
> keep them stable at very low temperatures, Himpsel
>
>says.
>
>
>
> The new memory was made without the use of lithography.
>
>To make conventional memory
>
> chips, light is used to etch patterns on a chemically
>
>treated silicon surface. To use
>
> lithography to make chips that are denser than the
>best
>
>available chips is prohibitively
>
> expensive and difficult.
>
>
>
> The new atomic-scale memory was made by evaporating
>
>gold onto a silicon wafer, which
>
> results in a precise track structure. By subsequently
>
>evaporating silicon onto the treated
>
> wafer, the Wisconsin team was able to diffuse silicon
>
>atoms across the structure where
>
> they line up and sit within the tracks like eggs in
>a
>
>carton. These silicon atoms represent
>
> the bits of information.
>
>
>
> Importantly, the atoms line up in such a way that
>there
>
>are atomically precise gaps
>
> between individual atoms, permitting scientists to
>
>pluck the particles out using the
>
> superfine tip of a scanning tunneling microscope
>
>without disturbing neighboring atoms and
>
> possibly creating unwanted chemical bonds.
>
>
>
> While the Wisconsin work proves the feasibility of
>
>atomic-scale memory and provides a
>
> platform for exploring the fundamental limits of data
>
>storage, the technology will require
>
> years, if not decades, of refinement to achieve a
>
>practical working memory that could be
>
> mass produced, Himpsel says. Obvious drawbacks, he
>
>notes, are the fact the memory was
>
> constructed and manipulated in a vacuum, and that
>a
>
>scanning tunneling microscope is
>
> needed to write memory which makes the writing process
>
>very time consuming.
>
>
>
> Moreover, there is a tradeoff between memory density
>
>and speed, Himpsel says. "As
>
> density increases, your ability to read the memory
>
>comes down because you get less and
>
> less of a signal. As you make things smaller, it's
>
>going to get slower."
>
>
>
> An intriguing aspect of the Wisconsin work is that
>
>memory density is comparable to the
>
> way nature stores data in DNA molecules. The Wisconsin
>
>atomic-scale silicon memory
>
> uses 20 atoms to store one bit of information,
>
>including the space around the single atom
>
> bits. DNA uses 32 atoms to store information in one
>
>half of the chemical base pair that is
>
> the fundamental unit that makes up genetic information.
>
>
>
>
>
> "Compared to conventional storage media, both DNA
>and
>
>the silicon surface excel by their
>
> storage density," says Himpsel.
>
>
>
> Co-authors of the Nanotechnology paper, published
>in
>
>the July 4, 2002 issue of
>
> Nanotechnology, include R. Bennewitz, J.N. Crain,
>A.
>
>Kirakosian, J-L. Lin, J.L. McChesney
>
> and D.Y. Petrovykh.
>
>
>
> For more information, visit:
>
>http://uw.physics.wisc.edu/~himpsel/memory.html
>
> # # #
>
> -- Terry Devitt (608) 262-8282,
>
>trdevitt@facstaff.wisc.edu
>
> Version for printing
--- Begin Message ---
http://www.news.wisc.edu/releases/view.html?id=7774
FOR IMMEDIATE RELEASE
9/3/02
CONTACT: Franz J. Himpsel (608) 263-5590, (608)
877-2000 fhimpsel@facstaff.wisc.edu
NOTE TO PHOTO EDITORS: To download a high-resolution
image to accompany this story,
visit: http://www.news.wisc.edu/newsphotos/atomic.html
SCIENTISTS DEVELOP ATOMIC-SCALE MEMORY
MADISON - In 1959, physics icon Richard Feynman, in a
characteristic
back-of-the-envelope calculation, predicted that all
the words written in the history of the
world could be contained in a cube of material one
two-hundredths of an inch wide -
provided those words were written with atoms.
Now, a little more than 40 years after Feynman's
prescient estimate, scientists at the
University of Wisconsin-Madison have created an
atomic-scale memory using atoms of
silicon in place of the 1s and 0s that computers use to
store data.
The feat, reported in the journal Nanotechnology,
represents a first crude step toward a
practical atomic-scale memory where atoms would
represent the bits of information that
make up the words, pictures and codes read by
computers.
"This is proof of concept of what Feynman was saying 40
years ago," says Franz Himpsel,
a UW-Madison professor of physics and the senior author
of the Nanotechnology paper.
Although the memory created by Himpsel and his
colleagues is in two dimensions rather
than the three-dimensional cube envisioned by Feynman,
it provides a storage density a
million times greater than a CD-ROM, today's
conventional means of storing data.
The atom, says Himpsel, represents the "hard wall" of
technological miniaturization. "We
seem to be at a natural limit."
Although divisible, the atom is a fundamental unit of
nature. They are the smallest
particles of an element and a single grain of sand, for
example, can contain 10 million
billion atoms.
The new memory was constructed on a silicon surface
that automatically forms furrows
within which rows of silicon atoms are aligned and rest
like tennis balls in a gutter. By
lifting out single silicon atoms with the tip of a
scanning tunneling microscope, the
Wisconsin team created gaps that represent the 0s of
data storage while atoms left in
place represent the1s.
Like conventional memory, the atomic-scale device can
be initialized, formatted, written
and read at room temperature.
By manipulating individual atoms at room temperature to
create memory, Himpsel and his
colleagues are treading a middle ground between atom
manipulation at very low
temperatures and conventional data storage, which
operates at room temperature but
uses millions of atoms per bit. It is far easier to
manipulate atoms one at a time and
keep them stable at very low temperatures, Himpsel
says.
The new memory was made without the use of lithography.
To make conventional memory
chips, light is used to etch patterns on a chemically
treated silicon surface. To use
lithography to make chips that are denser than the best
available chips is prohibitively
expensive and difficult.
The new atomic-scale memory was made by evaporating
gold onto a silicon wafer, which
results in a precise track structure. By subsequently
evaporating silicon onto the treated
wafer, the Wisconsin team was able to diffuse silicon
atoms across the structure where
they line up and sit within the tracks like eggs in a
carton. These silicon atoms represent
the bits of information.
Importantly, the atoms line up in such a way that there
are atomically precise gaps
between individual atoms, permitting scientists to
pluck the particles out using the
superfine tip of a scanning tunneling microscope
without disturbing neighboring atoms and
possibly creating unwanted chemical bonds.
While the Wisconsin work proves the feasibility of
atomic-scale memory and provides a
platform for exploring the fundamental limits of data
storage, the technology will require
years, if not decades, of refinement to achieve a
practical working memory that could be
mass produced, Himpsel says. Obvious drawbacks, he
notes, are the fact the memory was
constructed and manipulated in a vacuum, and that a
scanning tunneling microscope is
needed to write memory which makes the writing process
very time consuming.
Moreover, there is a tradeoff between memory density
and speed, Himpsel says. "As
density increases, your ability to read the memory
comes down because you get less and
less of a signal. As you make things smaller, it's
going to get slower."
An intriguing aspect of the Wisconsin work is that
memory density is comparable to the
way nature stores data in DNA molecules. The Wisconsin
atomic-scale silicon memory
uses 20 atoms to store one bit of information,
including the space around the single atom
bits. DNA uses 32 atoms to store information in one
half of the chemical base pair that is
the fundamental unit that makes up genetic information.
"Compared to conventional storage media, both DNA and
the silicon surface excel by their
storage density," says Himpsel.
Co-authors of the Nanotechnology paper, published in
the July 4, 2002 issue of
Nanotechnology, include R. Bennewitz, J.N. Crain, A.
Kirakosian, J-L. Lin, J.L. McChesney
and D.Y. Petrovykh.
For more information, visit:
http://uw.physics.wisc.edu/~himpsel/memory.html
# # #
-- Terry Devitt (608) 262-8282,
trdevitt@facstaff.wisc.edu
Version for printing
--- End Message ---