Intel and Numonyx report a breakthrough in new kind of memory chip

Intel and startup Numonyx said today they have accomplished a breakthrough in a new kind of memory chip that combines the best features of a variety of memory types. The “phase change memory” has been under research for years and the companies view it as a candidate for the ideal memory chip.
If this kind of chip can be manufactured, it can eventually be used in everything electronic from cell phones to servers in data centers.
Memory chips need to be fast, dense in terms of storage capacity, and hold their data even when the power is off. Nothing fits that bill right now. Dynamic random access memory chips used as main memory in personal computers is fast, but it loses data without an electrical charge. Flash memory is dense and holds data even if the power is turned off, but it is slower. And disk drives hold data when the power is off, but they’re slow compared to DRAM.
Today, Intel and Numonyx are demonstrating a prototype of a 64-megabit phase change chip that can be stacked three dimensionally on the same chip. That means the chip has multiple layers of memory cells, allowing it to be densely packed with storage cells. It can also be used for both random access (DRAM) functions and non-volatile memory (like Flash, where the memory is retained even without power).  And it doesn’t consume a lot of power. The initial chip has just one layer, but future chips are expected to be stackable.
Numonyx has been working on the technology for years and seemed to be lost in an endless research cycle. It was founded in 2000, and Intel is an investor. This new prototype chip, called a PCMS for phase change memory and switch, has a storage cell layered with what Numonyx calls an Ovonic Threshold Switch, which allows the cells to be stacked vertically yet accessed easily. The prototype uses a material which is an electrically-charged form of glass. This same kind of material is used in CD-ROM drives and non-volatile memory today.
Intel is doing the research to advance personal computing and is encouraged by the milestone, said Al Fazio, an Intel Fellow and director of memory technology development at the world’s biggest chip maker. But in a conference call, he said the companies were not ready to predict when they can manufacture commercial chips. He said he does expect that, because the memory can be stacked, that it will be able to store more memory in a given space than flash memory chips — the memory of choice in storing data in cell phones — which can’t be stacked that high.
Greg Atwood, senior technology fellow at Numonyx, also said the results are promising, since it shows the ideal memory is possible. If the chips are commercialized, they could be used in everything from mobile phones to data centers, Atwood said. Atwood said that research on memory technologies usually takes about ten years and he isn’t surprised that it has taken this long, given the need to test so many materials in manufacturing.
Memory cells are built by stacking a storage element (which stores a data bit) and a selector (which connects it to a larger array of memory cells). In this case, both use the same type of material. The companies will describe the chip more at the 2009 International Electron Devices Meeting in Baltimore, Md., on Dec. 9.
There are other kinds of new memory technologies under research. One of them, magnetic random access memory, is in production now, but it isn’t a stackable memory. In principle, Atwood said that there can be four or more layers of stacked memory with PCMS. The exact number of layers is yet to be determined.