A phase changing memory device, and method of making the same, that includes
programmable
memory material disposed between a pair of electrodes. The programmable memory
material includes discrete layers of phase change material, separated by conductive
interface layers, that exhibits relatively stable resistivity values over discrete
ranges of crystallizing and amorphousizing thermal pulses applied thereto, for
multi-bit storage. The memory material and one of the electrodes can be disposed
along spacer material surfaces to form an electrical current path that narrows
in width as the current path approaches the other electrode, such that electrical
current passing through the current path generates heat for heating the memory
material disposed between the electrodes.
