Alloy Holds Out Promise of Speedier Memory Chip
Scientists at IBM and two partner companies have developed a promising material that they believe will lead to a new kind of computer memory chip able to meet the growing appetite for storing digital music, pictures and video.
The advance will be described in a technical paper to be presented Monday at the International Electron Devices Meeting in San Francisco by researchers from IBM and two computer memory manufactures, Qimonda and Macronix. The scientists have designed a new semiconductor alloy derived from materials currently used in optical storage devices like CDs and DVDs.
This team is not the only entrant in the race to find alternatives to flash memory, the prevailing form of nonvolatile storage--so called because it can retain information without power. Intel and STMicroelectronics have formed a partnership to pursue the technology, and, separately, Samsung has made announcements in the field.
Intel has shown 128-megabit prototype chips and said it planned to introduce products in 2007. Samsung has described a 512-megabit prototype that it expects to market in 2008.
IBM scientists say their announcement is significant because the company s new material has performance advantages over alloys now in use in prototypes made by others in the industry
If the technology proves cheap enough to manufacture, it will create a new competitor in the $18.6 billion market for the inexpensive erasable memory chips that have proliferated in mobile phones, music players and other consumer gadgets in recent years.
Moreover, although IBM has withdrawn from the memory chip business, the company said it was intensely interested in the technology for corporate computing applications like transaction processing. Faster nonvolatile memory could change the design of the microprocessors that IBM makes, speeding up a variety of basic operations.
The new memory technology could potentially be added to a future generation of the IBM Power PC microprocessor, according to Spike Narayan, a senior manager at the company s Almaden Research Center here.
Over two and a half yeas, in a trial-and-error process, scientists here explored a class of materials that can be switched from an amorphous state to a crystalline one and then back again by repeated heating. The compounds, known as GST, or germanium-antimony-tellurium phase change materials, are routinely used today to make inexpensive optical disks that are read from and written to with laser beams.
The IBM led team has proved that the same effect can be realized by using a small electrical current. That has made it possible to build tiny memory cells that can store digital 1 s and 0 s by means of electricity rather than light. IBM scientists say the new material is an alloy composed of just germanium and antimony, and is referred to as GS. The scientists do not describe the material in detail in the paper.
The advantage of the new material, according to the scientists, is that it can be used to create switches more than 500 times as fast as today s flash chips. Moreover, the prototype switch developed by the scientists is just 3 nanometers high by 20 nanometers wide, offering the promise that the technology can be shrunk to smaller dimensions than could be attained by flash manufacturers.
The current generation of flash memory chips store as much as 32 billion bits on a chip .But that technology is likely to become increasingly problematic as chip makers struggle to reach ever finer dimensions.
Reached for comment later last week, Vivek Subramanian, an associate professor of electrical engineering at the University of California, Berkeley, who has read the technical paper describing the project, said, Everybody recognizes that scaling flash is going to be a problem in the long run. This looks like a really attractive technology that is both scaleable and consumes little power.
Industry executives said that the new materials might bolster the computer and consumer electronics industries just when it appeared they were nearing fundamental engineering limits.
This is a Christmas present for the industry because it shatters so many things at once, said Richard Doherty, president of Envisioneering, a computer industry consulting firm in Seaford, N.Y.，who has been briefed on the technical paper. This could change the basic equation between processors, local storage and communications.
Today s flash memories are largely divided into two distinct types called NOR and NAND, with different performance characteristics. The principal disadvantage of the flash design is that data cannot be addressed one bit at a time but only in larger blocks of data.
In contrast, phase change memories will be addressable at the bit level. Such a capability means that the new memories will be more flexible than flash memory and can be used in a wider variety of applications and computer designs.