Phase change memory electrode with sheath for reduced programming current

摘要

An example embodiment is a phase change memory cell that includes a bottom contact and an electrically insulating layer disposed over the bottom contact. The electrically insulating layer defines an elongated via. Furthermore, a bottom electrode is disposed at least partially in the via. The bottom electrode includes a sleeve of a first electrically conductive material surrounding a rod of a second electrically conductive material. The first electrically conductive material and the second electrically conductive material have different specific electrical resistances. The memory cell also includes a phase change layer electrically coupled to the first electrode.