How many Itaniums can you fit on the head of a pin?
HP boffins in molecular computing advance
Boffins at Hewlett-Packard are working with academics to develop chips so small they could fit on the head of a pin.
HP and UCLA yesterday announced they have received a US patent for technology that could make it possible to build very complex logic chips - simply and inexpensively - at the molecular scale.
The collaboration is pursuing molecular electronics as an entirely new technology that could augment silicon-based integrated circuits within the decade and eventually replace them. Silicon technology will reach its physical and economic limits by about 2012, HP believes.
The latest patent involves a process for dividing a minute chip into discrete zones, making it possible to build more complex circuits without running into problems from interference. The scientists had previously worked out how to fabricate a grid of nanowires just a few molecules wide.
Here's how HP explains the technology:
"Today's chip manufacturing process involves multiple, expensive precision steps to create the complex patterns of wires that define the computer circuit. The HP and UCLA invention proposes the use of a simple grid of wires - each wire just a few atoms wide - connected by electronic switches a single molecule thick.
"Previously, HP demonstrated in the laboratory how some rare earth metals naturally form themselves into nanoscopic parallel wires when they react chemically with a silicon substrate. Two sets of facing parallel wires, oriented roughly perpendicular to each other, could then be made into a grid, like a map of Manhattan in New York City with streets running east-west and avenues north-south."
"In a related experiment, researchers from the collaboration crossed wires the size of those used in today's computer chips and sandwiched them around a one-molecule thick layer of electrically switchable molecules called rotaxanes. Simple logic gates were then created electronically by downloading signals to molecules trapped between the crosswires."
While simple logic circuits have been formed in previous experiments, until the most recent patent, interference remained a barrier to creating more complex chips.
The solution proposed by the patented invention is to cut the wires into smaller lengths by turning some "intersections" into insulators. Insulators are created by "cutter wires," which are chemically distinct from the others. A voltage difference between the cutter wire and the target wire creates the insulator.
The latest patent, issued to Philip Kuekes and R. Stanley Williams of HP Labs and James R. Heath of UCLA, builds on previous patents and scientific work, including a patent for a memory chip based on molecular switches granted in 2000, by the company and university.
The work is being funded by a four-year, $12.5 million grant from the U.S. Defense Advanced Research Projects Agency and a $13.2 million investment from HP. ®