IBM researchers in Zurich have devised a single molecule switch. It can be flipped between two detectable 'on' and 'off' states by applying voltage pulses to it.

Both states are stable and data read-out is non-destructive. More than 500 switching cycles have been demonstrated by IBM's researchers, Heike Riel and Emanuel Lörtscher.

The specially-developed organic molecule is 1.5 nanometres in size, a hundredth of the size of a current CMOS element. It was designed and synthesised by Professor James M. Tour and co-workers of Rice University, Houston, USA.

CMOS technology will reach its ultimate limits in 10 to 15 years time. Chip structures currently have dimensions of about 40nm, and increasing size reductions are needed to continue the progression of Moore's Law. (This states that the transistor density of semiconductor chips will double roughly every 18 months.)

When chip elements shrink below the 20nm mark, more complex challenges arise and scaling appears not to be economically feasible any more.

There is also an increasing variability problem with CMOS process yields decreasing, because the individual elements are less and less identical. Below 10nm, the fundamental physical limits of CMOS technology will be reached.

"The main advantage of exploiting transport capabilities at the molecular scale is that the fundamental building blocks are much smaller than today's CMOS elements," explains lead researcher Heike Riel of the IBM Zurich Lab.

"Furthermore, chemical synthesis produces completely identical molecules, which, in principle, are building blocks with no variability. This allows us to avoid a known problem that CMOS devices face as they are scaled to ever smaller dimensions."

This IBM research could enable molecules to become possible building blocks for future memory and logic applications.

With dimensions of a single molecule of the order of one nanometer (one millionth of a millimeter), molecular electronics redefines the ultimate limit of miniaturisation far beyond that of today's silicon-based technology.

Single molecule memory elements could be the way we'll go in the future when CMOS technology hits the buffers.

The scientific paper entitled "Reversible and Controllable Switching of a Single-Molecule Junction" by E. Lörtscher, J. W. Ciszek, J. Tour, and H. Riel, was published in Small, Volume 2, Issue 8-9 , pp. 973-977 (04 August 2006).

Other molecular data storage research work can be found here.