An artificial neuron semiconductor device having a three-dimensional structure includes a first electrode to which a clock signal is applied, a second electrode in which an output signal is generated, an insulation column, a plurality of electrode layers for receiving an electrical signal from at least one synapse circuit, and a phase change layer which is divided into at least two parts by the insulation column and is in contact with at least two side surfaces of the insulation column, and the phase change layer is phase-changed by the plurality of electrode layers.

A method for locally annealing and crystallizing a thin film by directing ultrashort optical pulses from an ultrafast laser into the film. The ultrashort pulses can selectively produce an annealed pattern and/or activate dopants on the surface or within the film.

Three-dimensional (3D) non-volatile memory arrays having a vertically-oriented thin film transistor (TFT) select device and method of fabricating are described. The vertically-oriented TFT may be used as a vertical bit line selection device to couple a global bit line to a vertical bit line. A select device pillar includes a body and upper and lower source/drain regions. At least one gate is separated horizontally from the select device pillar by a gate dielectric. Each gate is formed over the gate dielectric and a base that extends horizontally at least partially between adjacent pillars. The base is formed with notches filled with the gate dielectric. The select device is fabricated using a conformally deposited base dielectric material and conformal hard mask layer that is formed with a larger bottom thickness than horizontal thickness. The base thickness is defined by the deposition thickness, rather than an uncontrolled etch back.

The semiconductor device includes a plurality of first conductive patterns on a substrate, a first selection pattern on each of the plurality of first conductive patterns, a first structure on the first selection pattern, a plurality of second conductive patterns on the first structures, a second selection pattern on each of the plurality of second conductive patterns, a second structure on the second selection pattern, and a plurality of third conductive patterns on the second structures. Each of the plurality of first conductive patterns may extend in a first direction. The first structure may include a first variable resistance pattern and a first heating electrode. The first variable resistance pattern and the first heating electrode may contact each other to have a first contact area therebetween. Each of the plurality of second conductive patterns may extend in a second direction crossing the first direction. The second structure may include a second variable resistance pattern and a second heating electrode. The second variable resistance pattern and the second heating electrode may contact each other to have a second contact area therebetween, and the second contact area may be different from the first contact area.

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.

Provided is a semiconductor apparatus including a plurality of semiconductor unit devices. Each of the semiconductor unit devices may be arranged between a first insulating layer and a second insulating layer that are apart from each other in a direction normal to a substrate. Each of the semiconductor unit devices may include a selection device layer and a phase change material layer that extend side by side in a direction parallel to the substrate. The phase change material layer may have a superlattice-like structure. The phase change material layer may be arranged along a recess portion that is formed by the first insulating layer, the second insulating layer, and the selection device layer.

Semiconductor unit devices may be arranged between a first insulating layer and a second insulating layer that are apart from each other in a direction normal to a substrate. Each of the semiconductor unit devices may include a selection device layer and a phase change material layer that extend side by side in a direction parallel to the substrate. The phase change material layer may have a superlattice-like structure. The phase change material layer may be arranged along a recess portion that is formed by the first insulating layer, the second insulating layer, and the selection device layer.

Heterostructures that include a bilayer composed of epitaxial layers of vanadium dioxide having different rutile-to-monoclinic phase transition temperatures are provided. Also provided are electrical switches that incorporate the heterostructures. The bilayers are characterized in that they undergo a single-step, collective, metal-insulator transition at an electronic transition temperature. At temperatures below the electronic transition temperature, the layer of vanadium dioxide having the higher rutile-to-monoclinic phase transition temperature has an insulating monoclinic crystalline phase, which is converted to a metallic monoclinic crystalline phase at temperatures above the electronic transition temperature.

A memory cell includes a heating element topped with a phase-change material. Two first silicon oxide regions laterally surround the heating element along a first direction. Two second silicon oxide regions laterally surround the heating element along a second direction orthogonal to the first direction. Top surfaces of the heating element and the two first silicon oxide regions are coplanar such that the heating element and the two first silicon oxide regions have a same thickness.

A nonvolatile memory apparatus includes a first electrode, a second electrode separated from the first electrode, a resistive-change material layer provided between the first electrode and the second electrode and configured to store information due to a resistance change caused by an electrical signal applied through the first electrode and the second electrode, and a diffusion prevention layer provided between the first electrode and the resistive-change material layer and/or between the second electrode and the resistive-change material layer and including a two-dimensional (2D) material having a monolayer thickness of about 0.35 nm or less.