Disclosed is a resistive switching element. The resistive switching element includes a first oxide layer and a second oxide layer stacked one on top of the other such that an interface is present therebetween, wherein the first oxide layer and the second oxide layer are made of different metal oxides; two-dimensional electron gas (2DEG) present in the interface between the first oxide layer and the second oxide layer and functioning as an inactive electrode; and an active electrode disposed on the second oxide layer, wherein when a positive bias is applied to the active electrode, an electric field is generated between the active electrode and the two-dimensional electron gas, such that the second oxide layer is subjected to the electric field, and active metal ions from the active electrode are injected into the second oxide layer. The resistive switching element realizes highly uniform resistive switching operation.

A RRAM device is provided. The RRAM device includes: a bottom electrode in a first dielectric layer; a switching layer in a second dielectric layer over the first dielectric layer, wherein a conductive path is formed in the switching layer when a forming voltage is applied; and a tapered top electrode region in a third dielectric layer over the second dielectric layer, wherein the tapered top electrode region extends downwardly into the switching layer.

A phase change memory (PCM) cell comprising a substrate a first electrode located on the substrate. A phase change material layer located adjacent to the first electrode, wherein a first side of the phase change material layer is in direct contact with the first electrode. A second electrode located adjacent to phase change material layer, wherein the second electrode is in direct contact with a second side of the phase change material layer, wherein the first side and the second side are different sides of the phase change material layer. An airgap is located directly above the phase change material layer, wherein the airgap provides space for the phase change material to expand or restrict.

Resistive random access memory (RRAM) cells, for example conductive bridging random access memory (CBRAM) cells and oxygen vacancy-based RRAM (OxRRAM) cells are provided. An RRAM cell may include a metal-insulator-metal (MIM) structure formed between adjacent metal interconnect layers or between a silicided active layer (e.g., including MOSFET devices) and a first metal interconnect layer. The MIM structure of the RRAM cell may be formed by a damascene process including forming a tub opening in a dielectric region, forming a cup-shaped bottom electrode in the tub opening, forming a cup-shaped insulator in an interior opening defined by the cup-shaped bottom electrode, and forming a top electrode in an interior opening defined by the cup-shaped insulator. The cup-shaped bottom electrode, or a component thereof (in the case of a multi-layer bottom electrode) may be formed concurrent with interconnect vias, e.g., by deposition of tungsten or other conformal metal.

Three-dimensional vertical memory array cell structures and processes. In an exemplary embodiment, a 3D vertical memory array structure is formed by performing operations that include forming an array stack having alternating metal layers and insulator layers, forming a hole through the array stack to expose internal surfaces of the metal layers and internal surfaces of the insulator layers, and performing a metal-oxidation process on the internal surfaces of the metal layers to form selector devices on the internal surfaces of the metal layers. The operations also include depositing one of resistive material or phase-change material within the hole on the selector devices and the internal surfaces of the insulator layers, such that the hole is reduced to a smaller hole, and depositing conductor material in the smaller hole.

Methods, systems, and devices for techniques for memory cells with sidewall and bulk regions in vertical structures are described. A memory cell may include a first electrode, a second electrode, and a self-selecting storage element between the first electrode and the second electrode. The bulk region may extend between the first electrode and the sidewall region. The bulk region may include a chalcogenide material having a first composition, and the sidewall region may include the chalcogenide material having a second composition that is different than the first composition. Also, the sidewall region may separate the bulk region from the second electrode.

Methods, systems, and devices for techniques for memory cells with sidewall and bulk regions in planar structures are described. A memory cell may include a first electrode, a second electrode, and a self-selecting storage element between the first electrode and the second electrode. A conductive path between the first electrode and the second electrode may extend in a direction away from a plane defined by a substrate. The self-selecting storage element may include a bulk region and a sidewall region. The bulk region may include a chalcogenide material having a first composition, and the sidewall region may include the chalcogenide material having a second composition that is different than the first composition. The bulk region and sidewall region may extend between the first electrode and the second electrode and in the direction away from the plane defined by the substrate.

Methods, systems, and devices for a memory device with laterally formed memory cells are described. A material stack that includes a conductive layer between multiple dielectric layers may be formed, where the conductive layer and dielectric layers may form a channel in a sidewall of the material stack. The channel may be filled with one or more materials, where a first side of an outermost material of the one or more materials may be exposed. An opening may be formed in the material stack that exposes a second side of at least one material of the one or more materials. The opening may be used to replace a portion of the at least one material with a chalcogenide material where the electrode materials may be formed before replacing the portion of the at least one material with the chalcogenide material.

Methods, systems, and devices for techniques that support sidewall structures for memory cells in vertical structures are described. A memory cell may include a first electrode, a second electrode, and a self-selecting storage element between the first electrode and the second electrode. The self-selecting storage element may extend between the first electrode and the second electrode in a direction that is parallel with a plane defined by the substrate. The self-selecting storage element may also include a bulk region and a sidewall region. The bulk region may include a chalcogenide material having a first composition, and the sidewall region may include the chalcogenide material having a second composition that is different than the first composition. Also, the sidewall region may extend between the first electrode and the second electrode.

A semiconductor storage device includes a first wiring, a second wiring, an insulating portion, and a resistance changing film. The first wiring extends in a first direction. The second wiring extends in a second direction intersecting the first direction, and is provided at a location different from that of the first wiring in a third direction intersecting the first direction and the second direction. The insulating portion is provided between the first wiring and the second wiring in the third direction. The resistance changing film is provided between the first wiring and the second wiring in the third direction, is adjacent to the insulating film from a first side and a second side which is opposite to the first side in the first direction, and the resistance changing film being smaller than the second wiring in the first direction.