SAN FRANCISCO The next-generation memory race continues to enfold, as several more vendors are jumping out of the starting blocks.
But a question remains in the arena: Will these devices ever become mainstream parts?
At the International Solid-State Circuits Conference (ISSCC) here, Intel Corp. and STMicroelectronics Inc. reached a milestone, as they begin shipping prototype samples of their previously-announced phase change memory (PCM) line. The 90-nm, 128-megabit product is slightly late to the market; the companies were supposed to ship the device late last year.
Meanwhile, in recent times, Freescale, NEC and others have rolled out rival MRAM devices. And Texas Instruments and others claim to be shipping another competitive technology called FRAM.
Others are pushing the limits of current technology. At ISSCC, SanDisk Corp. announced that it expects to start mass production of the world's first commercial three-bit-per-cell NAND flash memory in March or April. The technology was co-developed by its memory partner, Toshiba Corp.
SanDisk also announced the introduction of a standard multi-level (MLC) NAND flash memory, using 43-nm process technology. The technology was also co-developed with Toshiba.
And separately, Toshiba also rolled out the world's fastest embedded DRAM.
Next-generation memories--such as FRAM, MRAM, PCM and others--are supposed to replace today's DRAMs and flash memory technologies. Current memory devices are expected to hit the wall, as the floating-gate reaches its physical limits.
Today's flash memories are expected to scale at least to the 22-nm node, said Giulio Casagrande, director of advanced R&D in the Memory Products Group at STMicroelectronics Inc. DRAM scaling could end "even sooner," he told EE Times.
But after years of R&D, next-generation memories are still struggling to get off the starting blocks, due to manufacturing problems, cost and a lack of applications.
Some have been working on the technology for years--if not decades. Intel has been doing R&D on ovonic unified memory (OUM) -- or PCM -- with Ovonyx since 2000. At that time, Intel took a stake in that company. STMicroelectronics entered development with Ovonyx in 2001.
Intel and STMicroelectronics have finally shipped the product, after introducing the device last year. That device, codenamed ''Alverstone,'' is the first phase-change memory product from the companies.
Unofficially, the 90-nm, 128-Mbit part is being billed as a NOR flash compatible replacement. Cliff Smith, technical industry manager at Intel, said that the part provides fast read and write speeds at lower power than conventional flash, and allows for bit alterability normally seen in RAM.
Smith said that product sampling was "pushed out a couple of months," saying the device needed some additional mask steps. He did not elaborate, however. Some believe the part is several years late to the market, as the technology has been discussed for nearly three decades.
Meanwhile, the non-volatile memory technology is based on the electrically induced phase change of chalcogenide materials, which have been difficult to manufacture reliably in volumes. Phase-change materials have both crystalline and noncrystalline states that can represent "0" or "1," and it's possible to toggle between them by applying a small reset current.
"Alverstone" and future products will become a key part of Numonyx, a new independent semiconductor company created through an agreement between STMicroelectronics, Intel and Francisco Partners. Signed in May 2007, the venture is expected to close in the first quarter of 2008.
Others are pushing competitive technologies. For example, Japan's NEC recently claimed that it has developed the world's fastest MRAM. NEC's new ''SRAM-compatible, MRAM'' can operate at 250-MHz. The MRAM has a memory capacity of 1-megabit. Incorporating a memory cell with two transistors, one magnetic tunnel junction, and a newly-developed circuit scheme, the design achieves an operation speed of 250-MHz.
The MRAM is still in the development stages, and eventually, it will be targeted for select markets, said Masao Fukuma, senior vice president of NEC Electronics Corp. "Embedded memory is our first target," he told EE Times at ISSCC.
Others are extending current technology, which is expected to remain in the mainstream for several years. At ISSCC, SanDisk rolled out its three-bit-per-cell NAND flash memory technology, which was co-developed with Toshiba.
The first so-called x3 product, a 16-Gbit device, is based on 56-nm technology. x3 enables higher manufacturing efficiency and lower die cost for the same capital investment, according to SanDisk.
SanDisk and Toshiba also presented a joint paper on 43-nm 16-Gbit NAND flash memory. The 43-nm technology provides twice the density per chip, as compared to 56-nm process technology, thus lowering the die-cost. During the second quarter of 2008, SanDisk intends to begin shipping products. Shipments will start with 16-Gbit devices, followed by 32-Gbit parts in the second half of 2008.