Patent ID: 7868314

Claim:
A phase change memory (PCM) device, comprising: a first electrode; a first insulating layer, located on the first electrode; a phase change layer, located on the first insulating layer; a second insulating layer, located on the phase change layer, and forming a disk shape with the phase change layer; a center via, passing through the first insulating layer, the phase change layer, and the second insulating layer, and substantially corresponding to the center of the disk shape; a heating electrode, located in the center via, for performing Joule heating of the phase change layer; a third insulating layer, located on the first insulating layer and the second insulating layer, for covering the first insulating layer, the second electrode, and the second insulating layer; a ring via, passing through the third insulating layer and the second insulating layer, wherein the periphery of the ring via overlaps the edge of the phase change layer; and a second electrode, assuming a ring shape and located in the ring via.