HP technology lets future chips live with mistakes

IDG News Service - SAN FRANCISCO -- Researchers at Hewlett-Packard Co. believe they have developed a manufacturing technique that will allow chip makers to push the performance envelope after conventional transistors reach the atomic level, the company is expected to announce today.
The technique, based on a mathematical principle called coding theory, will let future generations of microprocessor circuits be reliably manufactured in high volumes, according to HP.
Developed as part of HP Labs' "crossbar latch" research project, which aims to replace the microprocessor transistor within the decade, the technique will be described in the June 6 issue of the Institute of Physics' Nanotechnology journal.
Rather than using transistors, crossbar latch circuits will use microscopic wires known as nanowires that are placed at a right angle to a separate set of parallel nanowires. This creates an electrical field that can be switched between two states, creating the "1" and "0" bits necessary for computing. A nanowire is a solid tube that can be as thin as the width of a single carbon atom.
Basically, HP has discovered a method of ensuring that these silicon nanowires continue to function even if manufacturing defects partially sever the connection between the crossbar and the rest of the circuit, said Stan Williams, a senior fellow and director of HP's Quantum Research Lab.
This is an important advance, since the crossbar design will catch on with chip makers only if it can be reliably manufactured in high volumes, said Phil Kuekes, a senior computer architect at HP. And in order to do that, HP needs to make sure it can work around defects that inevitably crop up in the manufacturing process, he said.
Enter coding theory, a mathematical technique that helps a digital signal travel down a noisy wire without losing its clarity. Developed by Claude Shannon, a researcher at Bell Labs and MIT in the 1940s and 1950s, coding theory involves adding small pieces of information to a transmission in order to ensure the data is accurately received, Kuekes said.

Mobile phones already transmit information using coding theory, Williams said. A mobile phone turns a user's voice into digital bits of information, which are then sent through the air to a receiver. To make sure those digital bits of information are properly reassembled into speech, the phone adds small pieces of information to the packets of digital bits that help identify each bit and prevent calls from garbling the message, he said.
Much in the way coding theory is used to clear up mobile phone calls, it could