A phase change memory element including at least one phase change material layer, and a heater conductor, wherein at least a portion of the heater conductor is circumferentially surrounded by the at least one phase change material layer. The phase change memory element is symmetrical. The phase change memory element can include a top electrode circumferentially surrounding and connected to the at least one phase change material layer, and a bottom electrode in contact with the heater conductor. The phase change memory element can include at least one resistive liner in contact with the at least one phase change material layer.

A memory cell with a recessed bottom electrode and methods of forming the memory cell are described. A bottom electrode can be deposited on a layer of a structure. A first insulator and a second insulator can be deposited on top of the bottom electrode. The first insulator and the second insulator can be spaced apart from one another to form an opening on top of the bottom electrode. A recess can be etched in the bottom electrode. The recess can be etched in a portion of the bottom electrode that is underneath the opening. The recess and the opening can form a pore. Phase change material can be deposited in the pore to form a memory cell.

A phase change memory (PCM) device is provided. The PCM device includes a bottom electrode formed on a substrate, a heater electrode formed on the bottom electrode, the heater electrode having a tapered portion that becomes narrower in a direction away from the substrate. The PCM device also includes an interlayer dielectric (ILD) layer formed on the tapered portion of the heater electrode, the interlayer layer dielectric including an airgap that at least partially surrounds the tapered portion of the heater electrode. The PCM device also includes a phase change layer formed on the heater electrode, and a top electrode formed on the phase change layer.

Embodiments of the present invention include a phase change memory (PCM) array. The PCM array may include a plurality of PCM cells. Each PCM cell in the plurality of PCM cells may include a top electrode, a resistive element, and a bottom electrode. The PCM array may also include a global heater surrounding the plurality of PCM cells having a thermally conductive material contacting each of the plurality of PCM cells. The global heater may be configured to receive an electric signal to heat the plurality of PCM cells simultaneously.

A semiconductor device includes a PCM stack that includes bottom electrode liner over a lower heater. The bottom electrode liner has a top-down view plus (+) geometry with a ‘horizontal’ portion being orthogonal to a ‘vertical’ portion. An airgap is formed within the PCM stack in an area located adjacent and between the ‘horizontal’ portion and the ‘vertical’ portion. The airgap has a substantially smaller dielectric constant than the surrounding PCM stack material(s). Therefore, the airgap may effectively reduce the amount of current that leaks from the PCM stack when flowing from the bottom electrode liner to a top contact or top electrode. Further, the airgap may allow for expansion of the surrounding PCM stack material(s) that may result from the heating of the PCM stack.

A phase change memory element has a memory region, a first electrode and a second electrode. The memory region is arranged between the first and the second electrodes and has a bulk zone and an active zone. The memory region is made of a germanium, antimony and tellurium based alloy, wherein germanium is in a higher percentage than antimony and tellurium in the bulk zone of the memory region. The active zone is configured to switch between a first stable state associated with a first memory logic level and a second stable state associated with a second memory logic level. The active zone has, in the first stable state, a uniform, amorphous structure and, in the second stable state, a differential polycrystalline structure including a first portion, having a first stoichiometry, and a second portion, having a second stoichiometry different from the first stoichiometry.

A phase change material memory device is provided. The phase change material memory device includes one or more electrical contacts in a substrate, and a dielectric cover layer on the electrical contacts and substrate. The phase change material memory device further includes a lower conductive shell in a trench above one of the one or more electrical contacts, and an upper conductive shell on the lower conductive shell in the trench. The phase change material memory device further includes a conductive plug filling the upper conductive shell. The phase change material memory device further includes a liner layer on the dielectric cover layer and conductive plug, and a phase change material block on the liner layer on the dielectric cover layer and in the trench.

A memory device includes two phase change memory (PCM) cells and a bridge. The first PCM cell includes an electrical input and a phase change material. The second PCM cell includes an electrical input that is independent from the electrical input of the first PCM cell and another phase change material. The bridge is electrically connected to the two PCM cells.

A method for producing a memory device includes depositing a second interlayer insulating film on a substrate, forming contact holes, and depositing a second metal and a nitride film. The second metal and the nitride film are removed to form pillar-shaped nitride layers, and to form lower electrodes surrounding the pillar-shaped nitride layers. The second interlayer insulating film is etched back to expose upper portions of the lower electrodes. The upper portions of the lower electrodes surrounding the pillar-shaped nitride film are removed and a phase change film is deposited to surround the pillar-shaped nitride film and connect with the lower electrodes. The phase change film is etched on upper portions of the pillar-shaped nitride film, and a reset gate insulating film is formed surrounding the phase change film and forming a reset gate having a side wall shape and remaining on the upper portions of the pillar-shaped nitride film.

A two-terminal device comprises a bottom electrode. A device element is formed upon the bottom electrode. The two-terminal device also comprises a top electrode that is formed upon the device element. The bottom electrode and the top electrode are aligned. The bottom electrode and top electrode also have a same width and depth.