Patent ID: 7956358

Claim:
A memory device comprising: first and second electrodes, vertically separated and having mutually opposed contact surfaces; a phase change cell, including an upper phase change member, having a contact surface in electrical contact with the first electrode; a lower phase change member, having a contact surface in electrical contact with the second electrode; a kernel member disposed between and in electrical contact with the upper and lower phase change members, and a barrier metal layer interposed between the lower phase change member and the kernel member; wherein the phase change cell is formed of material having at least two solid phases; and the lateral extent of the upper and lower phase change members is substantially greater than that of the kernel member; and an intermediate thermal isolation layer is disposed between the upper and lower phase change members adjacent to the kernel member, the intermediate thermal isolation layer comprising a material having a thermal conductivity lower than that of a surrounding dielectric material, the memory device further including thin film barrier metal layers having a thickness of about 10 nm or less, interposed between the first electrode and the lower phase change member; the lower phase change member and the intermediate thermal isolation layer; and between the upper phase change member and the intermediate thermal isolation layer.