Overview of candidate device technologies for storage-class memory

Storage-class memory (SCM) combines the benefits of a solid-state memory, such as high performanee and robustness, with the archival capabilities and low cost of conventional hard-disk magnetic storage. Sueh a device would require a solid-state nonvolatile memory technology that could be manufactured at an extremely high effective areal density using some combination of sublithographie patterning techniques, multiple bits per cell, and multiple layers of devices. We review the candidate solid-state nonvolatile memory technologies that potentially could be used to construet such an SCM. We discuss evolutionary extensions of conventional flash memory, such as SONOS (silicon-oxide-nitride-oxide-silicon) and nanotraps, as well as a number of revolutionary new memory technologies. We review the capabilities of ferroelectrie, magnetie, phase-change, and resistive random-access memories, including perovskites and solid electrolytes, and finally organic and polymeric memory. The potential for practical sealing to ultrahigh effective areal density for each of these candidate technologies is then compared. © Copyright 2008 by International Business Machines Corporation.