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Since the 1940s, Oak Ridge National
Laboratory has played a leading role
in the development of ion beam technology
and its application in materials processing
and characterization. A key advance
was made in the early 1960s when,
in one of the first applications of
computers in materials science, researchers
predicted that positive ions (charged
atoms) moving through a crystal would
follow channels between the rows of
atoms, thereby penetrating well into
the crystal structure. The "ion channeling"
effect became the basis for valuable
scientific and commercial processes
used to force ions into materials
as a means of tailoring or altering
their properties. One such process
is ion implantation, now developed
into a fine art that relies on accelerators
to drive selected ions into materials
at precise distances. Many materials
so modified are now in routine use.
Today, Oak Ridge operates a facility
where the broader scientific community
carries out fundamental research on
various ion beam techniques to selectively
design the near-surface properties
of materials.
Scientific Impact:
Ion beam techniques are widely used
for research on topics such as superconductivity,
thin-film electrolytes, quasicrystals,
and surface structure and chemistry.
The science continues to evolve; new
approaches to controlling the morphology
and properties of ion-implanted materials
and layers now are being developed
based on defect physics.
Social Impact: Ion
implantation is used extensively in
the electronics industry to "dope"
semiconductors with special properties,
both chemically and spatially. The
process is also used to improve the
wear resistance of titanium alloys
in artificial prostheses for hip and
knee replacements. By eliminating
the need to rework failed replacement
joints, this technology spares individuals
from additional surgeries and saves
as much as $100 million per year.
Reference: E. Chason,
et al, "Ion beams in silicon processing
and characterization," Journal
of Applied Physics, vol. 81,
no. 10, pp. 6513-6561 (1997) [Report
of BES study panel]
A. Agarwal, H.-J. Gossmann, D. J.
Eaglesham, S. B. Herner, A. T. Fiory,
and T. E. Haynes, "Boron-enhanced
diffusion of boron from ultra-low
energy ion implantation," Applied
Physics Letters vol. 74, pp.
2435-2437 (1999).
J. M. Williams and R. A. Buchanan,
"Ion implantation of surgical Ti-6Al-4V
alloy," Materials Science and
Engineering vol. 69, pp. 237-246
(1985).
URL:
http://www.ssd.ornl.gov/Org/Surfaces.html
Technical Contact:
Don Freeburn, Office of Basic Energy
Sciences, 301-903-3156
Press Contact: Jeff
Sherwood, DOE Office of Public Affairs,
202-586-5806
SC-Funding Office:
Office of Basic Energy Sciences |