Editing Phase-change memory (section)

===Samsung 46.7 nm cell===
In September 2006, [[Samsung]] announced a prototype 512[[Megabit|&nbsp;Mb]] (64[[Megabyte|&nbsp;MB]]) device using [[diode]] switches.<ref name=samsung>[http://www.samsung.com/us/business/semiconductor/newsView.do?news_id=766.0 SAMSUNG Introduces the Next Generation of Nonvolatile Memory—PRAM]</ref> The announcement was something of a surprise, and it was especially notable for its fairly high [[Density (computer storage)|memory density]]. The prototype featured a cell size of only 46.7&nbsp;nm, smaller than commercial [[Flash memory|flash]] devices available at the time. Although flash devices of higher ''capacity'' were available (64[[Gigabit|&nbsp;Gb]], or 8[[Gigabyte|&nbsp;GB]], was just coming to market), other technologies competing to replace flash in general offered lower densities (larger cell sizes). The only production [[Magnetoresistive RAM|MRAM]] and [[FeRAM]] devices are only 4&nbsp;Mb, for example. The high density of Samsung's prototype PRAM device suggested it could be a viable flash competitor, and not limited to niche roles as other devices have been. PRAM appeared to be particularly attractive as a potential [[NOR flash replacement|replacement for NOR flash]], where device capacities typically lag behind those of [[NAND flash memory|NAND]] flash devices. State-of-the-art capacities on NAND passed 512&nbsp;Mb some time ago. [[NOR flash]] offers similar densities to Samsung's PRAM prototype and already offers bit addressability (unlike NAND where memory is accessed in banks of many bytes at a time).