IBM on Monday announced that it was working with Infineon Technologies and Macronix International to develop memory technology that could in the future replace flash memory chips in computers and portable storage devices.
Phase-Change Memory (PCM) technology uses a special material, called phase-change material, to store memory data. It can change its structure from an amorphous to a crystalline state by using electrons to pass energy through the material, said Chung Lam, manager of the PCM project at IBM.
Computer memory stores data in the form of zeros and ones. With PCM technology, the material's state represents this information, with an amorphous form, or indefinite structure, representing 0 and a crystalline, or definite, structure representing 1.
PCM offers several advantages over flash memory technology, including greater reliability, Lam said. It does not use floating gates, which flash memory chips use to store information. This makes PCM faster and more reliable. "It is more reliable because there are no moving parts involved like in flash memory. We can change the status [of material] without floating gates," he said.
Flash memory uses floating gates to store electrons, which represents the binary data. With PCM, resistors are used instead of floating gates, he said.
"Floating gate stores a large number of electrons. More than a thousand electrons [in flash memory] represent one state of binary. In PCM, the resistance of the material represents the binary data. PCM stores 1 and 0 in the state of material," Lam said.
PCM will provide quicker read and write capabilities than flash memory, Lam said. In PCM, "you can directly write without erase. In flash memory, you need to erase before you can write," he said. Even if the device containing PCM is shut down, the memory retains data, making it nonvolatile memory. Flash memory is also a non-volatile memory type.
Research on the technology is in its early stages, and PCM could hit the market in three to five years, Lam said. "We are looking at it as a research project, whether we can actually make any memory as [fast] or faster than flash memory," he said. It could be used in products ranging from servers to consumer electronics, according to the company.
IBM has in the past worked with Germany-based Infineon Technologies on memory technologies, Lam said. Taiwan-based Macronix brings in manufacturing expertise, he said.
Twenty to 25 employees from the three companies will be dedicated to the PCM research, which will be conducted at IBM's research centers in Yorktown Heights, New York, and San Jose, California, according to IBM.