LONDON Ė Jai Menon, an IBM Fellow and chief technology officer with IBM's systems and technology group, has confirmed that IBM believes that phase-change memory (PCM), a non-volatile technology, could scale beyond where flash memory can go and could be of use in server computers in three to five years. Menon said he expects IBM to continue to develop its own PCM intellectual property but the company would likely offer that to a memory chip maker that could supply PCM components to IBM for use in server systems.
In a telephone interview with EE Times Menon said IBM is "very bullish" about PCM in the next three to five years and that it could have a role to play in server memory systems replacing flash memory. Flash is already making in-roads there because of the need to save power in server farms. Further out IBM's magnetic race-track memory could replace PCM, Menon said.
However, there are still a number of challenges to be overcome as Menon acknowledged. Menon did not provide EE Times with specific evidence of breakthroughs to address heater scalability or thermal limitations except to refer to a PCM array copper ionic conduction access-device paper published by authors from IBM at the Symposium on VLSI Technology published this year .
However, that access device is aimed at use in a stacked structure where thermal cross-talk has the potential to be an even more severe problem.
PCM is based on changing the material phase and the electrical resistance of a chalcogenide layer in each memory cell through the use of electrical heating. It is an attractive technology because of its non-volatility, theoretical high density and bit-alterability and has been touted as a possible replacement for both flash memory and DRAM. But the technology has proved difficult to commercialize and even as devices have made it to market using 90-nm and 65-nm process technologies, questions have been asked about the ability to scale the technology beyond flash memory, which is already being made at close to 22-nm.