Jeff Hanna Nanoscale Electronics 4.23.09 Gameplan Why is memory - PowerPoint PPT Presentation

Jeff Hanna Nanoscale Electronics 4.23.09

Gameplan • Why is memory important? • Background of MRAM • Basic Elements of MRAM • Fabrication • Comparison • Applications • Current Value of Market

! Early MRAMs – anisotropic magnetoresistance " B is mag field, when off current flows between rims " When on, the resistance between rims goes up

! Giant Magnetoresistance " Triggered the new field of electronics called spintronics ! Demo http://www.research.ibm. com/research/demos/g mr/1.swf

! Conventional MRAM " Single step write op " Substaintial current needed " Overlapping fields occur when scaling below 180nm

! Toggle­mode MRAM " Utilizes multi­step writing " Can be scaled much smaller " Less power needed

! 1 transistor 1 magnetic tunnel junction (1T1MTJ)

! Read: ­V applied to BL relative to SL. Current flows through MTJ. Sense amplifier decides “1” or ‘0” ! Write: “0” +V applied Note: The smaller the to SL and BL and vice MTJ is or the longer the versa when writing “1” writing pulse is applied, the less critical switching current is needed

! Magnetic Tunnel Junction (MTJ) is storage element ! Tunnel magnetoresistance (TMR) defined by: " ! R/R = ( R AP !"#$" ) %#$

Aerospace and military systems ! Digital cameras ! Notebooks ! Smart cards ! Mobile telephones ! Cellular base stations ! Personal Computers ! Battery-Backed SRAM replacement ! Datalogging specialty memories ! (black box solutions) Media players ! Book readers !

! Memory is important ! MRAM has evolved past R&D ! MTJ provide low power nonvolatile memory ! Fabrication is similar to current techniques ! MRAM is comparable to become universal memory ! The memory market is estimated to sky rocket and MRAM could grab a majority of market share