As the flash memories used in many electronic devices, such as digital cameras and cell phones, are reaching their physical limits for data storage, the most likely candidate to succeed them is based on the material used in rewritable CDs and DVDs, an article in the July 11 issue of the journal Science says.
Flash memory works by electrically charging a transistor. This charge remains stored for a long time, but smaller flash memories than the ones being built today would not retain the charge as well as the current ones do.
A type of memory that uses phase-change materials—the components of rewritable CDs and DVDs—would make a good substitute for flash memory, writes Greg Atwood, a senior fellow in the Research and Development Group of the semiconductor company Numonyx. These new memories work by creating a rapid, reversible physical change in the structure of the transistor’s material. The two phases—crystalline and amorphous—have different conductivities that can be exploited in electronic memories. This new kind of memory can be rewritten more times than flash memories and could be built smaller, too.—Maria José Viñas
