Get ready to say goodbye to system RAM and flash-based solid-state drives... eventually. After several years of joint research, Intel and Numonyx, the chipmaker's former NOR flash division, have announced a "key breakthrough" in the development of phase-change memory (PCM): a 64Mb test chip that "enables the ability to stack, or place, multiple layers of PCM arrays within a single die."
As the two companies point out, phase-change memory combines "many of the benefits" of system RAM and flash memory. Like system RAM, PCM can write single bits or bytes instead of whole blocks, and it can do so with very little latency and similar read bandwidth (but lower write bandwidth). PCM is also non-volatile, meaning it remembers data even after the device is powered off, just like flash memory.
With this breakthrough, Intel and Numonyx expect to make PCM considerably cheaper to produce than before—there was talk in the conference call of a cost structure much like that of NAND flash memory, which powers today's solid-state drives, with similar density increases over time and without compromised performance. The two firms see the potential for "collapsing" existing memory types (such as NAND and DRAM) into PCM in future devices.
Here's the nitty-gritty about the test chip, in the words of Intel and Numonyx:
Memory cells are built by stacking a storage element and a selector, with several cells creating memory arrays. Intel and Numonyx researchers were able to deploy a thin film, two-terminal OTS as the selector, matching the physical and electrical properties for PCM scaling. With the compatibility of thin-film PCMS, multiple layers of cross point memory arrays are now possible. Once integrated together and embedded in a true cross point array, layered arrays are combined with CMOS circuits for decoding, sensing and logic functions.
The two companies didn't discuss a time frame for commercial applications, but they'll reveal more about their breakthrough in a paper at the 2009 International Electron Devices Meeting in Baltimore, Maryland on December 9. Until then, you can check out a white paper (PDF) about PCM on Numonyx's website.
Once commercial products start to roll out—and if PCM write speeds catch up to those of DRAM—we could eventually see computers with a single, massive pool of PCM acting as both lightning-quick mass storage and memory. That could translate into near-instantaneous boot and application load times, among other perks.