Atom lithography, shooting sculpted beams of atoms at a substrate,
can create lines of deposited atoms with widths as narrow as 50 nm.
Two groups in Holland have separately carried out experiments in which
atoms, heated in an oven, released through a baffle, cooled
by laser rays striking the beam at right angles, and then focused in
optical microlenses consisting of opposing laser beams.
In the case of physicists at Eindhoven University of Technology (contact
Ton van Leeuwen, 31-40-2474094, firstname.lastname@example.org) the best resulting
grid of iron atoms had lines only 50 nm wide and spaced consistently
186 nm apart. The researchers expect to achieve 10-nm lines, but their
chief aim is to move from producing simple grid patterns to making more
elaborate patterns with holographic and other techniques. They are also
pursuing a "single-point writer" option, in which the full
atomic beam will be focused to a single, very intense spot.
What is the advantage of such slow atom-beam approach to lithography?
Mainly it is the directness of the method for inscribing microcircuitry
(no etching or use of masks) and exercising great control over line
width and spacing. The researchers also admit that there are imposing
technological hurdles to using this approach on an industrial scale.
Short-term applications would most likely be for making MEMS-like structures
(te Sligte et al.,
Applied Physics Letters, November 8, 2004; lab website at http://www.phys.tue.nl/aow).
The other Dutch group, at Radboud University Nijmegen, has laid down
their own grid of iron atoms with lines 95 nm in width, 186 nm apart,
and covering an area of 1.6 x .4 mm2. (Myszkiewicz
et al., Applied Physics Letters, October 25, 2004; contact
Theo Rasing, 31-24-3653102) The two groups are now working together
on some joint ventures.