August 30, 2010
Advances Offer Path to Shrink Computer Chips Again
By JOHN MARKOFF
Scientists at Rice University and Hewlett-Packard are reporting this week that they can overcome a fundamental barrier to the continued rapid miniaturization of computer memory that has been the basis for the consumer electronics revolution.
In recent years the limits of physics and finance faced by chip makers had loomed so large that experts feared a slowdown in the pace of miniaturization that would act like a brake on the ability to pack ever more power into ever smaller devices like laptops, smartphones and digital cameras.
But the new announcements, along with competing technologies being pursued by companies like IBM and Intel, offer hope that the brake will not be applied any time soon.
In one of the two new developments, Rice researchers are reporting in Nano Letters, a journal of the American Chemical Society, that they have succeeded in building reliable small digital switches — an essential part of computer memory — that could shrink to a significantly smaller scale than is possible using conventional methods.
More important, the advance is based on silicon oxide, one of the basic building blocks of today’s chip industry, thus easing a move toward commercialization. The scientists said that PrivaTran, a Texas startup company, has made experimental chips using the technique that can store and retrieve information.
These chips store only 1,000 bits of data, but if the new technology fulfills the promise its inventors see, single chips that store as much as today’s highest capacity disk drives could be possible in five years. The new method involves filaments as thin as five nanometers in width — thinner than what the industry hopes to achieve by the end of the decade using standard techniques. The initial discovery was made by Jun Yao, a graduate researcher at Rice. Mr. Yao said he stumbled on the switch by accident.
Separately, H.P. is to announce on Tuesday that it will enter into a commercial partnership with a major semiconductor company to produce a related technology that also has the potential of pushing computer data storage to astronomical densities in the next decade. H.P. and the Rice scientists are making what are called memristors, or memory resistors, switches that retain information without a source of power.
“There are a lot of new technologies pawing for attention,” said Richard Doherty, president of the Envisioneering Group, a consumer electronics market research company in Seaford, N.Y. “When you get down to these scales, you’re talking about the ability to store hundreds of movies on a single chip.”
The announcements are significant in part because they indicate that the chip industry may find a way to preserve the validity of Moore’s Law. Formulated in 1965 by Gordon Moore, a co-founder of Intel, the law is an observation that the industry has the ability to roughly double the number of transistors that can be printed on a wafer of silicon every 18 months.
That has been the basis for vast improvements in technological and economic capacities in the past four and a half decades. But industry consensus had shifted in recent years to a widespread belief that the end of physical progress in shrinking the size modern semiconductors was imminent. Chip makers are now confronted by such severe physical and financial challenges that they are spending $4 billion or more for each new advanced chip-making factory.
I.B.M., Intel and other companies are already pursuing a competing technology called phase-change memory, which uses heat to transform a glassy material from an amorphous state to a crystalline one and back.
Phase-change memory has been the most promising technology for so-called flash chips, which retain information after power is switched off.
The flash memory industry has used a number of approaches to keep up with Moore’s law without having a new technology. But it is as if the industry has been speeding toward a wall, without a way to get over it.
To keep up speed on the way to the wall, the industry has begun building three-dimensional chips by stacking circuits on top of one another to increase densities. It has also found ways to get single transistors to store more information. But these methods would not be enough in the long run.
The new technology being pursued by H.P. and Rice is thought to be a dark horse by industry powerhouses like Intel, I.B.M., Numonyx and Samsung. Researchers at those competing companies said that the phenomenon exploited by the Rice scientists had been seen in the literature as early as the 1960s.
“This is something that I.B.M. studied before and which is still in the research stage,” said Charles Lam, an I.B.M. specialist in semiconductor memories.
H.P. has for several years been making claims that its memristor technology can compete with traditional transistors, but the company will report this week that it is now more confident that its technology can compete commercially in the future.
In contrast, the Rice advance must still be proved. Acknowledging that researchers must overcome skepticism because silicon oxide has been known as an insulator by the industry until now, Jim Tour, a nanomaterials specialist at Rice said he believed the industry would have to look seriously at the research team’s new approach.
“It’s a hard sell, because at first it’s obvious it won’t work,” he said. “But my hope is that this is so simple they will have to put it in their portfolio to explore.”