Innovative technologies for high density non-volatile semiconductor memories

Abstract

In the last decade, the impressive growth of the portable systems market has been also sustained by the availability of successful semiconductor Non-Volatile Memory (NVM) technologies. The key driver has been the Flash memory, in particular the NAND Flash, the preeminent NVM technology for the mass storage application in portable electronic systems. The needs for higher and higher density memory will continuously grow, driven, for example, by the needs of huge amount of memory for the long video recording. In this contest is growing the industrial interest to explore new technologies able to guarantee a density increase beyond, and cost competitive with, existing NAND Flash. The paper presents innovative NVM technologies, that exploit new materials, different physical storage concepts and also alternative memory array architectures with respect to the Flash memories of today, with particular attention to the minimum cell size passive arrays (cross-point memory), based on ferroeletric or conductive polymers, on magnetic tunnel junction and on chalcogenide alloy. A final section is dedicated to the mechanical decoded probe storage technology, the so-called “seek and scan” approach, like the one used in Hard-Disk or Compact-Disk, that could have interesting applications in several fields, ranging from the mass storage application to molecular manipulation, thus tracing the route for the post-Moore’s law NVM development.