Moore's law dictates that every two years, the number of
components squeezed onto an integrated circuit will double. To
fit it all in, transistors will have to shrink to the size of
single atoms by the year 2020. But microengineers at the
University of New South Wales think they're well ahead of
schedule, after making a working transistor that consists of a
single phosphorus atom, placed precisely in a silicon crystal.
Single-atom transistors have been made before, but with a margin
of error of around ten nanometres. Researchers also have to
search through many devices, or tune multi-atom devices to
isolate one that works. "But this device is perfect", says
Professor Michelle Simmons, director of the ARC Centre for
Quantum Computation and Communication Technology at UNSW. "This
is the first time anyone has shown control of a single atom in a
substrate with this level of precise accuracy." The device
consists of an individual atom placed between atomic-scale
electrodes and electrostatic control gates. The micr