Update: Carbon-Nanotube Wiring Gets Real

Could carbon nanotubes have a shot at replacing the copper wires that connect millions of transistors on today´s silicon chips? Chip makers replaced aluminum interconnects with better conducting copper ones about seven years ago, but now copper´s days are numbered too. Higher- performance chips with more- tightly packed transistors, expected as soon as 2012, will need interconnects less than 40 nanometers wide, at which point copper´s resistance will slow signaling down too much. Late last month, at the Materials Research Society´s spring meeting in San Francisco, a team of engineers from Stanford and Toshiba reported that they have used carbon nanotubes to wire logic-circuit components on a conventional silicon CMOS chip. They claim to have shown that nanotubes can shuttle data at speeds of a little faster than 1 gigahertz, close to the range of state-of-the-art microprocessors, which run at speeds of 2 to 3 GHz.