SET to RESET Programming in Phase Change Memories

Experimental data on details of SET (crystalline) to RESET (amorphous) transition are presented for Ge
₂
Sb
₂
Te
₅
(GST) nonvolatile memory cell. It is shown that the main source of heat for a SET to RESET transition is the GST bulk and interface regions instead of the contacting electrode. A small-contact-area electrode is used primarily to supply current into and minimize heat loss from the chalcogenide. Increasing bottom contact resistivity offers a scaling path for RESET current with no electrical penalties