Editing Phase-change memory (section)

===Aluminum/antimony===
Phase-change memory devices based on [[germanium]], [[antimony]] and [[tellurium]] present manufacturing challenges, since etching and polishing of the material with [[chalcogen]]s can change the material's composition. Materials based on [[Aluminium|aluminum]] and antimony are more thermally stable than [[GeSbTe]]. [[Aluminium antimonide|Al<sub>50</sub>Sb<sub>50</sub>]] has three distinct resistance levels, offering the potential to store three bits of data in two cells as opposed to two (nine states possible for the pair of cells, using eight of those states yields log<sub>2</sub>&nbsp;8&nbsp;=&nbsp;3&nbsp;bits).<ref>{{cite web|url=http://www.kurzweilai.net/will-phase-change-memory-replace-flash-memory |title=Will phase-change memory replace flash memory? |publisher=KurzweilAI |access-date=2013-09-17}}</ref><ref>{{Cite journal | last1 = Zhou | first1 = X. | last2 = Wu | first2 = L. | last3 = Song | first3 = Z. | last4 = Rao | first4 = F. | last5 = Ren | first5 = K. | last6 = Peng | first6 = C. | last7 = Song | first7 = S. | last8 = Liu | first8 = B. | last9 = Xu | first9 = L. | last10 = Feng | first10 = S. | doi = 10.1063/1.4818662 | title = Phase transition characteristics of Al-Sb phase change materials for phase change memory application | journal = Applied Physics Letters | volume = 103 | issue = 7 | pages = 072114 | year = 2013 | bibcode = 2013ApPhL.103g2114Z }}</ref>

[[File:PRAM cell structure.svg|thumb|300px|right|A cross-section of two PRAM memory cells. One cell is in low resistance crystalline state, the other in high resistance amorphous state.]]