Abstract: A resistor array for multi-bit data storage without the need to increase the size of a memory chip or scale down the feature size of a memory cell contained within the memory chip is provided. The resistor array incorporates a number of discrete resistive elements to be selectively connected, in different series combinations, to at least one memory cell or memory device. In one configuration, by connecting each memory cell or device with at least one resistor array, a resistive switching layer found in the resistive switching memory element of the connected memory device is capable of being at multiple resistance states for storing multiple bits of digital information. During device programming operations, when a desired series combination of the resistive elements within the resistor array is selected, the resistive switching layer in the connected memory device can be in a desired resistance state.

Abstract: Embodiments of the invention include nonvolatile memory elements and memory devices comprising the nonvolatile memory elements. Methods for forming the nonvolatile memory elements are also disclosed. The nonvolatile memory element comprises a first electrode layer, a second electrode layer, and a plurality of layers of an oxide disposed between the first and second electrode layers. One of the oxide layers has linear resistance and substoichiometric composition, and the other oxide layer has bistable resistance and near-stoichiometric composition. Preferably, the sum of the two oxide layer thicknesses is between about 20 ? and about 100 ?, and the oxide layer with bistable resistance has a thickness between about 25% and about 75% of the total thickness. In one embodiment, the oxide layers are formed using reactive sputtering in an atmosphere with controlled flows of argon and oxygen.

Abstract: Provided are methods of forming nonvolatile memory elements using atomic layer deposition techniques, in which at least two different layers of a memory element are deposited sequentially and without breaking vacuum in a deposition chamber. This approach may be used to prevent oxidation of various materials used for electrodes without a need for separate oxygen barrier layers. A combination of signal lines and resistive switching layers may be used to cap the electrodes and to minimize their oxidation. As such, fewer layers are needed in a memory element. Furthermore, atomic layer deposition allows more precise control of electrode thicknesses. In some embodiments, a thickness of an electrode may be less than 50 Angstroms. Overall, atomic layer deposition of electrodes and resistive switching layers lead to smaller thicknesses of entire memory elements making them more suitable for low aspect ratio features of advanced nodes.

Abstract: A resistor structure incorporated into a resistive switching memory cell with improved performance and lifetime is provided. The resistor structure may be a two-terminal structure designed to reduce the maximum current flowing through a memory cell. A method is also provided for making such a memory cell. The method includes depositing a resistor structure and depositing a variable resistance layer of a resistive switching memory cell of the memory cell, where the resistor structure is disposed in series with the variable resistance layer to limit the switching current of the memory cell. The incorporation of the resistor structure is very useful in obtaining desirable levels of switching currents that meet the switching specification of various types of memory cells. The memory cells may be formed as part of a high-capacity nonvolatile memory integrated circuit, which can be used in various electronic devices.

Abstract: Embodiments of the invention generally relate to memory devices and methods for fabricating such memory devices. In one embodiment, a method for fabricating a resistive switching memory device includes depositing a metallic layer on a lower electrode disposed on a substrate and exposing the metallic layer to an activated oxygen source while heating the substrate to an oxidizing temperature within a range from about 300° C. to about 600° C. and forming a metal oxide layer from an upper portion of the metallic layer during an oxidation process. The lower electrode contains a silicon material and the metallic layer contains hafnium or zirconium. Subsequent to the oxidation process, the method further includes heating the substrate to an annealing temperature within a range from greater than 600° C. to about 850° C. while forming a metal silicide layer from a lower portion of the metallic layer during a silicidation process.

Abstract: A nonvolatile memory element is disclosed comprising a first electrode, a near-stoichiometric metal oxide memory layer having bistable resistance, and a second electrode in contact with the near-stoichiometric metal oxide memory layer. At least one electrode is a resistive electrode comprising a sub-stoichiometric transition metal nitride or oxynitride, and has a resistivity between 0.1 and 10? cm. The resistive electrode provides the functionality of an embedded current-limiting resistor and also serves as a source and sink of oxygen vacancies for setting and resetting the resistance state of the metal oxide layer. Novel fabrication methods for the second electrode are also disclosed.

Abstract: A nonvolatile resistive memory element has a novel variable resistance layer that includes a metal nitride, a metal oxide-nitride, a two-metal oxide-nitride, or a multilayer stack thereof. One method of forming the novel variable resistance layer comprises an interlayer deposition procedure, in which metal oxide layers are interspersed with metal nitride layers and then converted into a substantially homogeneous layer by an anneal process. Another method of forming the novel variable resistance layer comprises an intralayer deposition procedure, in which various ALD processes are sequentially interleaved to form a metal oxide-nitride layer. Alternatively, a metal oxide is deposited, nitridized, and annealed to form the variable resistance layer or a metal nitride is deposited, oxidized, and annealed to form the variable resistance layer.

Abstract: Embodiments of the invention generally relate to nonvolatile memory devices and methods for manufacturing such memory devices. The methods for forming improved memory devices, such as a ReRAM cells, provide optimized, atomic layer deposition (ALD) processes for forming a metal oxide film stack which contains at least one hard metal oxide film (e.g., metal is completely oxidized or substantially oxidized) and at least one soft metal oxide film (e.g., metal is less oxidized than hard metal oxide). The soft metal oxide film is less electrically resistive than the hard metal oxide film since the soft metal oxide film is less oxidized or more metallic than the hard metal oxide film. In one example, the hard metal oxide film is formed by an ALD process utilizing ozone as the oxidizing agent while the soft metal oxide film is formed by another ALD process utilizing water vapor as the oxidizing agent.

Abstract: A nonvolatile memory element is disclosed comprising a first electrode, a near-stoichiometric metal oxide memory layer having bistable resistance, and a second electrode in contact with the near-stoichiometric metal oxide memory layer. At least one electrode is a resistive electrode comprising a sub-stoichiometric transition metal nitride or oxynitride, and has a resistivity between 0.1 and 10 ?cm. The resistive electrode provides the functionality of an embedded current-limiting resistor and also serves as a source and sink of oxygen vacancies for setting and resetting the resistance state of the metal oxide layer. Novel fabrication methods for the second electrode are also disclosed.

Abstract: Provided are resistive random access memory (ReRAM) cells including resistive switching layers and thermally isolating structures for limiting heat dissipation from the switching layers during operation. Thermally isolating structures may be positioned within a stack or adjacent to the stack. For example, a stack may include one or two thermally isolating structures. A thermally isolating structure may directly interface with a switching layer or may be separated by, for example, an electrode. Thermally isolating structures may be formed from materials having a thermal conductivity of less than 1 W/m*K, such as porous silica and mesoporous titanium oxide. A thermally isolating structure positioned in series with a switching layer generally has a resistance less than the low resistance state of the switching layer. A thermally isolating structure positioned adjacent to a switching layer may have a resistance greater than the high resistance state of the switching layer.

Abstract: Provided are methods of forming nonvolatile memory elements using atomic layer deposition techniques, in which at least two different layers of a memory element are deposited sequentially and without breaking vacuum in a deposition chamber. This approach may be used to prevent oxidation of various materials used for electrodes without a need for separate oxygen barrier layers. A combination of signal lines and resistive switching layers may be used to cap the electrodes and to minimize their oxidation. As such, fewer layers are needed in a memory element. Furthermore, atomic layer deposition allows more precise control of electrode thicknesses. In some embodiments, a thickness of an electrode may be less than 50 Angstroms. Overall, atomic layer deposition of electrodes and resistive switching layers lead to smaller thicknesses of entire memory elements making them more suitable for low aspect ratio features of advanced nodes.

Abstract: Provided are semiconductor devices, such as resistive random access memory (ReRAM) cells, that include current limiting layers formed from alloys of transition metals. Some examples of such alloys include chromium containing alloys that may also include nickel, aluminum, and/or silicon. Other examples include tantalum and/or titanium containing alloys that may also include a combination of silicon and carbon or a combination of aluminum and nitrogen. These current limiting layers may have resistivities of at least about 1 Ohm-cm. This resistivity level is maintained even when the layers are subjected to strong electrical fields and/or high temperature processing. In some embodiments, the breakdown voltage of a current limiting layer is at least about 8V. The high resistivity of the layers allows scaling down the size of the semiconductor devices including these layers while maintaining their performance.

Abstract: Provided are ReRAM cells, each having at least one interface between an electrode and a resistive switching layers with a maximum field value of less than 0.25. The electrode materials forming such interfaces include tantalum nitrides doped with lanthanum, aluminum, erbium yttrium, or terbium (e.g., TaX(Dopant)YN, where X is at least about 0.95). The electrode materials have low work functions (e.g., less than about 4.5 eV). At the same time, the resistive switching materials have high relative dielectric permittivities (e.g., greater than about 30) and high electron affinities (greater than about for 3.5 eV). Niobium oxide is one example of a suitable resistive switching material. Another electrode interfacing the resistive switching layer may have different characteristics and, in some embodiments, may be an inert electrode.

Abstract: A nonvolatile memory element is disclosed comprising a first electrode, a near-stoichiometric metal oxide memory layer having bistable resistance, and a second electrode in contact with the near-stoichiometric metal oxide memory layer. At least one electrode is a resistive electrode comprising a sub-stoichiometric transition metal nitride or oxynitride, and has a resistivity between 0.1 and 10 ?cm. The resistive electrode provides the functionality of an embedded current-limiting resistor and also serves as a source and sink of oxygen vacancies for setting and resetting the resistance state of the metal oxide layer. Novel fabrication methods for the second electrode are also disclosed.

Abstract: Provided are carbon doped resistive switching layers, resistive random access memory (ReRAM) cells including these layers, as well as methods of forming thereof. Carbon doping of metal containing materials creates defects in these materials that allow forming and breaking conductive paths as evidenced by resistive switching. Relative to many conventional dopants, carbon has a lower diffusivity in many suitable base materials. As such, these carbon doped materials exhibit structural stability and consistent resistive switching over many operating cycles. Resistive switching layers may include as much as 30 atomic percent of carbon, making the dopant control relatively simple and flexible. Furthermore, carbon doping has acceptor characteristics resulting in a high resistivity and low switching currents, which are very desirable for ReRAM applications. Carbon doped metal containing layer may be formed from metalorganic precursors at temperatures below saturation ranges of atomic layer deposition.

Abstract: A nonvolatile resistive memory element has a novel variable resistance layer that includes a metal nitride, a metal oxide-nitride, a two-metal oxide-nitride, or a multilayer stack thereof. One method of forming the novel variable resistance layer comprises an interlayer deposition procedure, in which metal oxide layers are interspersed with metal nitride layers and then converted into a substantially homogeneous layer by an anneal process. Another method of forming the novel variable resistance layer comprises an intralayer deposition procedure, in which various ALD processes are sequentially interleaved to form a metal oxide-nitride layer. Alternatively, a metal oxide is deposited, nitridized, and annealed to form the variable resistance layer or a metal nitride is deposited, oxidized, and annealed to form the variable resistance layer.

Abstract: Systems and methods for preparing resistive switching memory devices such as resistive random access memory (ReRAM) devices wherein both oxide and nitride layers are deposited in a single chamber are provided. Various oxide and nitride based layers in the ReRAM device such as the switching layer, current-limiting layer, and the top electrode (and optionally the bottom electrode) are deposited in the single chamber. By fabricating the ReRAM device in a single chamber, throughput is increased and cost is decreased. Moreover, processing in a single chamber reduces device exposure to air and to particulates, thereby minimizing device defects.

Abstract: Embodiments of the invention generally relate to nonvolatile memory devices and methods for manufacturing such memory devices. The methods for forming improved memory devices, such as a ReRAM cells, provide optimized, atomic layer deposition (ALD) processes for forming a metal oxide film stack which contains at least one hard metal oxide film (e.g., metal is completely oxidized or substantially oxidized) and at least one soft metal oxide film (e.g., metal is less oxidized than hard metal oxide). The soft metal oxide film is less electrically resistive than the hard metal oxide film since the soft metal oxide film is less oxidized or more metallic than the hard metal oxide film. In one example, the hard metal oxide film is formed by an ALD process utilizing ozone as the oxidizing agent while the soft metal oxide film is formed by another ALD process utilizing water vapor as the oxidizing agent.

Abstract: Provided are semiconductor devices, such as resistive random access memory (ReRAM) cells, that include current limiting layers formed from alloys of transition metals. Some examples of such alloys include chromium containing alloys that may also include nickel, aluminum, and/or silicon. Other examples include tantalum and/or titanium containing alloys that may also include a combination of silicon and carbon or a combination of aluminum and nitrogen. These current limiting layers may have resistivities of at least about 1 Ohm-cm. This resistivity level is maintained even when the layers are subjected to strong electrical fields and/or high temperature processing. In some embodiments, the breakdown voltage of a current limiting layer is at least about 8V. The high resistivity of the layers allows scaling down the size of the semiconductor devices including these layers while maintaining their performance.

Abstract: Provided are methods of forming nonvolatile memory elements using atomic layer deposition techniques, in which at least two different layers of a memory element are deposited sequentially and without breaking vacuum in a deposition chamber. This approach may be used to prevent oxidation of various materials used for electrodes without a need for separate oxygen barrier layers. A combination of signal lines and resistive switching layers may be used to cap the electrodes and to minimize their oxidation. As such, fewer layers are needed in a memory element. Furthermore, atomic layer deposition allows more precise control of electrode thicknesses. In some embodiments, a thickness of an electrode may be less than 50 Angstroms. Overall, atomic layer deposition of electrodes and resistive switching layers lead to smaller thicknesses of entire memory elements making them more suitable for low aspect ratio features of advanced nodes.