Single-atom transistor beats Moore's Law by eight years (Wired UK)

Single-atom transistor beats Moore's Law by eight years

By Mark Brown

20 February 12

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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 microscopic device even has tiny visible markers etched onto its surface so engineers can connect metal contacts and apply a voltage.

To make it, the team popped a crystal inside an ultra-high vacuum chamber and then used a scanning tunnelling microscope (STM) to manipulate individual atoms. They placed phosphorus atoms on the crystal then covered them with a layer of hydrogen

Select hydrogen atoms were then removed with the metal tip of the microscope, and a controlled chemical reaction incorporated phosphorus atoms into the silicon surface. Finally, the structure was coated in silicon, and metallic connects were attached.

Transistors are semiconductor devices which can amplify and switch electronic signals when current is applied to one pair of the transistor's terminals. They're a fundamental part of almost all electronic devices.

When they're made at this size, not only can you get more processing power from a tiny chip, but they could be used to build a quantum computer: one that uses the various phenomena of quantum mechanics -- superposition and entanglement and so on -- to perform calculations much faster.

via wired.co.uk