Compositionally matched nitrogen-doped Ge_2Sb_2Te_5/Ge_2Sb_2Te_5 superlattice-like structures for phase change random access memory

摘要

A compositionally matched superlattice-like (SLL) structure comprised of Ge_2Sb_2Te_5 (GST) and nitrogen-doped GST (N-GST) was developed to achieve both low current and high endurance Phase Change Random Access Memory (PCRAM). N-GST/GST SLL PCRAM devices demonstrated ～37% current reduction compared to single layered GST PCRAM and significantly higher write/ erase endurances of ～10～8 compared to ～10～6 for GeTe/Sb_2Te_3 SLL devices. The improvements in endurance are attributed to the compositionally matched N-GST/GST material combination that lowers the diffusion gradient between the layers and the lower crystallization-induced stress in the SLL as revealed by micro-cantilever stress measurements.