A semiconductor device includes gate electrodes on a substrate, a channel and a resistance pattern. The gate electrodes are spaced apart from each other in a vertical direction substantially perpendicular to an upper surface of the substrate. The channel extends through the gate electrodes in the vertical direction on the substrate. The resistance pattern includes a phase-changeable material. The resistance pattern includes a first vertical extension portion on a sidewall of the channel and extending in the vertical direction, a first protrusion portion on an inner sidewall of the first vertical extension portion and protruding in a horizontal direction substantially parallel to the upper surface of the substrate, and a second protrusion portion on an outer sidewall of the first vertical extension portion and protruding in the horizontal direction and not overlapping the first protrusion portion in the horizontal direction.

Circuits and methods that enable stacking of phase change material (PCM) switches and that accommodate variations in the resistance of the resistive heater(s) of such switches. Stacking is enabled by providing isolation switches for the resistive heater(s) in a PCM switch to reduce parasitic capacitance caused by the proximity of the resistive heater(s) to the PCM region of a PCM switch. Variations in the resistance of the resistive heater(s) of a PCM switch are mitigated or eliminated by sensing the actual resistance of the resistive heater(s) and then determining a suitable adjusted electrical pulse profile for the resistive heater(s) that generates a precise thermal pulse to the PCM region, thereby reliably achieving a desired switch state while extending the life of the resistive heater(s) and the phase-change material.

A memristor includes a bottom electrode, a top electrode, and an active region disposed therebetween. The active region has an electrically conducting filament in an electrically insulating medium, extending between the bottom electrode and the top electrode. The memristor further includes a temperature gradient element for controlling switching.

A method for fabricating a semiconductor device includes forming air gaps within respective dielectric layer portions to reduce thermal cross-talk between adjacent bits. Each of the dielectric portions is formed on a substrate each adjacent to sidewall liners formed on sidewalls of a phase change memory (PCM) layer. The method further includes forming a pillar including the sidewall liners and the PCM layer, and forming a selector layer on the pillar and the dielectric portions.

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 and semiconductor device includes forming pillar-shaped phase change layers and lower electrodes in two or more rows and two or more columns on a semiconductor substrate. A reset gate insulating film is formed that surrounds the pillar-shaped phase change layers and the lower electrodes, and a reset gate is formed that surrounds the pillar-shaped phase change layers that function as memory devices arranged in two or more rows and two or more columns.

A phase-change memory element with an electrically isolated conductor is provided. The phase-change memory element includes: a first electrode and a second electrode; a phase-change material layer electrically connected to the first electrode and the second electrode; and at least two electrically isolated conductors, disposed between the first electrode and the second electrode, directly contacting the phase-change material layers.

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 resistive random access memory is provided to solve the problem of low switching speed of the conventional resistive random access memory. The resistive random access memory may include a thermally conductive layer, a first electrode layer, a heat preserving element, a resistance changing layer and a second electrode layer. The first electrode layer is arranged on the thermally conductive layer. The heat preserving element is arranged on the first electrode layer and forms a through-hole. A part of a surface of the first electrode layer is exposed to the through-hole. The resistance changing layer extends from the part of the surface of the first electrode layer to a surface of the heat preserving element that is located outside the through-hole. The second electrode layer is arranged on the resistance changing layer.

Some embodiments include methods of forming structures. Spaced-apart features are formed which contain temperature-sensitive material. Liners are formed along sidewalls of the features under conditions which do not expose the temperature-sensitive material to a temperature exceeding 300° C. The liners extend along the temperature-sensitive material and narrow gaps between the spaced-apart features. The narrowed gaps are filled with flowable material which is cured under conditions that do not expose the temperature-sensitive material to a temperature exceeding 300° C. In some embodiments, the features contain memory cell regions over select device regions. The memory cell regions include first chalcogenide and the select device regions include second chalcogenide. The liners extend along and directly against the first and second chalcogenides.