A memory cell formed in a pillar structure between a first electrode and a second electrode includes laminated encapsulation structure. In one example, the pillar includes a body of ovonic threshold switch material, carbon-based intermediate layers, metal layers and a body of phase change memory material in electrical series between the first and second electrodes. The laminated encapsulation structure surrounds the pillar. The laminated dielectric encapsulation structure comprises at least three conformal layers, including a first layer of material, a second conformal layer of a second layer material different from the first layer material; and a third conformal layer of a third layer material different from the second layer material.

A semiconductor storage device includes a memory cell including a core portion that extends in a first direction above a semiconductor substrate; a variable resistance layer that extends in the first direction and is in contact with the core portion; a semiconductor layer that extends in the first direction and is in contact with the variable resistance layer; a first insulator layer that extends in the first direction and is in contact with the semiconductor layer; and a first voltage applying electrode that extends in a second direction orthogonal to the first direction and is in contact with the first insulator layer. The core portion is a vacuum region, or a region containing inert gas.

In some embodiments, the present disclosure relates to a method of forming an integrated chip that includes depositing a phase change material layer over a bottom electrode. The phase change material is configured to change its degree of crystallinity upon temperature changes. A top electrode layer is deposited over the phase change material layer, and a hard mask layer is deposited over the top electrode layer. The top electrode layer and the hard mask layer are patterned to remove outer portions of the top electrode layer and to expose outer portions of the phase change material layer. An isotropic etch is performed to remove portions of the phase change material layer that are uncovered by the top electrode layer and the hard mask layer. The isotropic etch removes the portions of the phase change material layer faster than portions of the top electrode layer and the hard mask layer.

A phase change memory device based on a nano current channel is provided. A nano current channel layer structure is adopted and configured to limit the current channel. As such, when flowing through the layer, the current enters the phase change layer from nano crystal grains with high electrical conductivity, and the current is thereby confined in the nano current channels. By using the nano-scale conductive channels, the contact area between the phase change layer and the electrode layer is significantly decreased, the current density at local contact channel is significantly increased, and heat generation efficiency of the current in the phase change layer is improved. Moreover, an electrically insulating and heat-insulating material with low electrical conductivity and low thermal conductivity prevents heat in the phase change layer from being dissipated to the electrode layer, and Joule heat utilization efficiency of the phase change layer is thereby improved.

Insulated phase change memory devices are provided that include a first electrode; a second electrode; a phase change material disposed in an electrical path between the first electrode and the second electrode; and a porous dielectric configured to concentrate heat produced by a reset current carried through the phase change material between the first electrode and the second electrode to mitigate an amount of heat that escapes from the phase change material. The porous dielectric may be an inherently porous dielectric material or a dielectric material in which porous structures are induced during fabrication. Methods of fabrication of such devices are also provided.

A memory cell includes a bottom electrode, a storage element layer, a first buffer layer, and a top electrode. The storage element layer is disposed over the bottom electrode. The first buffer layer is interposed between the storage element layer and the bottom electrode, where a thermal conductivity of the first buffer layer is less than a thermal conductivity of the storage element layer. The top electrode is disposed over the storage element layer, where the storage element layer is disposed between the top electrode and the first buffer layer.

A memory, system, and method to improve integration density while maintaining thermal efficiency through a phase change memory cell with a superlattice based thermal barrier. The phase change memory may include a bottom electrode. The phase change memory may also include an active phase change material. The phase change memory may also include a superlattice thermal barrier proximately connected to the active phase change material. The phase change memory may also include a top electrode proximately connected to the superlattice thermal barrier. The system may include the phase change memory cell. The method for forming a phase change memory may include depositing an active phase change material on a bottom electrode. The method may also include depositing a superlattice thermal barrier proximately connected to the active phase change material. The method may also include depositing a top electrode proximately connected to the superlattice thermal barrier.

A phase change memory, a system, and a method to prevent high resistance drift within a phase change memory through a phase change memory cell with three terminals and self-aligned metal contacts. The phase change memory may include a bottom electrode. The phase change memory may also include a heater proximately connected to the bottom electrode. The phase change memory may also include a phase change material proximately connected to the heater. The phase change memory may also include metal proximately connected to at least two sides of the phase change material. The phase change memory may also include three terminals, where a bottom terminal is located at an area proximately connected to the heater and two top terminals are located at areas proximately connected to the metal.

A phase change memory (PCM) structure configured for performing a gradual reset operation includes first and second electrodes and a phase change material layer disposed between the first and second electrodes. The PCM structure further includes a thermal insulation layer disposed on at least sidewalls of the first and second electrodes and phase change material layer. The thermal insulation layer is configured to provide non-uniform heating of the phase change material layer. Optionally, the thermal insulation layer may be formed as an air gap. The PCM structure may be configured having the first and second electrodes aligned in a vertical or a lateral arrangement.

A phase-change memory device includes a bottom electrode; a stack of alternating electrical conductor layers directly contacting a top surface of the bottom electrode; a metal pillar directly contacting a top surface of the stack; a phase change material element directly contacting a top surface of the metal pillar; and a top electrode on the phase change material element, wherein a lateral dimension of the metal pillar is smaller than that of the stack.