Abstract: Provided are methods of fabricating memory cells such as resistive random access memory (ReRAM) cells. A method involves forming a first layer including two high-k dielectric materials such that one material has a higher dielectric constant than the other material. In some embodiments, hafnium oxide and titanium oxide form the first layer. The higher-k material may be present at a lower concentration. In some embodiments, a concentration ratio of these two high-k materials is between about 3 and 7. The first layer may be formed using atomic layer deposition. The first layer is then annealed in an oxygen-containing environment. The method may proceed with forming a second layer including a low-k dielectric material, such as silicon oxide, and forming an electrode. After forming the electrode, the memory cell is annealed in a nitrogen containing environment. The nitrogen anneal may be performed at a higher temperature than the oxygen anneal.

Abstract: Metal silicon nitride nanolaminates are formed at temperatures of 200-400 C by alternating ALD monolayers or thin CVD layers of metal nitride and silicon nitride. The silicon nitride layers are formed from a silicon halide precursor, causing nitrogen bonds to replace the halogen bonds, which is a lower-energy reaction than bonding nitrogen to elemental silicon. The silicon content, and thereby the resistivity, of the nanolaminate can be tuned by either a sub-saturation dose of the silicon halide precursor (forming ALD sub-monolayers) or by the relative number of metal nitride and silicon nitride layers. Resistivities between 1 and 500 ?·cm, suitable for ReRAM embedded resistors, can be achieved. Some of the nanolaminates can function as combination embedded resistors and electrodes.

Abstract: Provided are resistive random access memory (ReRAM) cells having switching layers that include hafnium, aluminum, oxygen, and nitrogen. The composition of such layers is designed to achieve desirable performance characteristics, such as low current leakage as well as low and consistent switching currents. In some embodiments, the concentration of nitrogen in a switching layer is between about 1 and 20 atomic percent or, more specifically, between about 2 and 5 atomic percent. Addition of nitrogen helps to control concentration and distribution of defects in the switching layer. Also, nitrogen as well as a combination of two metals helps with maintaining this layer in an amorphous state. Excessive amounts of nitrogen reduce defects in the layer such that switching characteristics may be completely lost. The switching layer may be deposited using various techniques, such as sputtering or atomic layer deposition (ALD).

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: Compound layers, such as metal silicon nitrides, are formed by ALD or CVD from precursors with incompatible reaction temperature ranges. The substrate is held at a temperature within the lower reaction temperature range (e.g., that of a metal precursor). The low-temperature precursor and its reactant react to form an ALD monolayer or thin CVD layer. The high-temperature precursor and its reactant are pulsed in the chamber, and the substrate is irradiated with ultraviolet light. The ultraviolet light adds energy to the system to overcome the reaction barrier despite the substrate temperature being below the minimum reaction temperature of the high-temperature precursor.

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 methods of forming nitrides at low substrate temperatures, such as less than 500° C. or even less than 400° C. The nitrides can be formed using atomic layer deposition (ALD), chemical vapor deposition (CVD), and other like techniques. The low substrate temperatures allow using various temperature sensitive precursors, such as Tetrakis(DiMethylAmino)Hafnium (i.e., TDMAHf) or TertiaryButylimido-Tris(DiEthylamino)Tantalum (i.e., TBTDET), to form nitrides of components provided by these precursors. Furthermore, the low temperatures preserve other structures present on the substrate prior to forming the nitride layers. Nitrogen-containing precursors with low dissociation energy are used in these methods. Some examples of such nitrogen-containing precursors include hydrazine (N2H4), diazene (N2H2), triazene (N3H3), triazane (N3H5), alkyl-substituted variations thereof, and salts thereof. Also provided are methods of forming oxy-nitrides using low substrate temperatures.

Abstract: Ternary oxides, nitrides and oxynitrides of the form (a)(b)OxNy are formed by ALD or CVD when the reaction temperature ranges of the (a) precursor and the (b) precursor do not overlap. Chemically-reacted sub-layers, e.g., (a)OxNy, are formed by reacting the lower-temperature precursor with O and/or N at a temperature within its reaction range. Physisorbed sub-layers (e.g., (b) or (b)+ligand) are formed between the chemically-reacted sub-layers by allowing the higher-temperature precursor to physically adsorb to the low-temperature surface. When the desired sub-layers are formed, the substrate is heated to a temperature at which the higher-temperature precursor reacts (optionally in the presence of more O and/or N) to form (a)(b)OxNy. Quarternary and more complex compounds can be similarly formed.

Abstract: A method of fabricating a resistive random access memory (ReRAM) cell may include forming a set of nanolaminate structures over an electrode, such that each structure includes at least one first element oxide layer and at least one second element oxide layer. The overall set is operable as a resistive switching layer in a ReRAM cell. In this set, an average atomic ratio of the first element to the second element is different in at least two nanolaminate structures. This ratio may be less in nanolaminate structures that are closer to electrodes than in the middle nanolaminate structures. Alternatively, this ratio may increase from one end of the set to another. The first element may be less electronegative than the second elements. The first element may be hafnium, while the second element may be one of zirconium, aluminum, titanium, tantalum, or silicon.

Abstract: Selective wet etching is used to produce feature sizes of reduced width in semiconductor devices. An initial patterning step (e.g., photolithography) forms a pillar of an initial width from at least a selected first layer and an overlayer. A wet etchant that is selective to the selected layer undercuts the sidewalls of the selected layer to a smaller width while leaving at least part of the overlayer in place to protect the top surface of the selected layer. The selected layer becomes a narrow “stem” within the pillar, and may have dimensions below the resolution limit of the technique used for the initial patterning. For some devices, voids may be intentionally left in a fill layer around the stem for electrical or thermal insulation.

Abstract: A nonvolatile memory device contains a resistive switching memory element with improved device switching performance and lifetime by custom tailoring the average concentration of defects in the resistive switching film and methods of forming the same. The nonvolatile memory element includes a first electrode layer, a second electrode layer, and a resistive switching layer disposed between the first electrode layer and the second electrode layer. The resistive switching layer comprises a first sub-layer and a second sub-layer, wherein the first sub-layer has more defects than the first sub-layer. A method includes forming a first sub-layer on the first electrode layer by a first ALD process and forming a second sub-layer on the first sub-layer by a second ALD process, where the first sub-layer has a different amount of defects than the second sub-layer.

Abstract: Forming a resistive switching layer having a vertical interface can generate defects confined along the interface between two electrodes. The confined defects can form a pre-determined region for filament formation and dissolution, leading to low power resistive switching and low program voltage or current variability. In addition, the filament forming process of the resistive memory device can be omitted due to the existence of the confined defects.

Abstract: A nonvolatile resistive memory element includes a novel switching layer and methods of forming the same. The switching layer includes a material having bistable resistance properties and formed by bonding silicon to oxygen or nitrogen. The switching layer may include at least one of SiOx, SiOxNy, or SiNx. Advantageously, the SiOx, SiOxNy, and SiNx generally remain amorphous after thermal anneal processes are used to form the devices, such as ReRAM devices.

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 resistive random access memory (ReRAM) cells and methods of fabricating thereof. A ReRAM cell includes an embedded resistor and resistive switching layer connected in series. The embedded resistor prevents excessive electrical currents through the resistive switching layer, especially when the resistive switching layer is switched into its low resistive state, thereby preventing over-programming. The embedded resistor includes aluminum, nitrogen, and one or more additional metals (other than aluminum). The concentration of each component is controlled to achieve desired resistivity and stability of the embedded resistor. In some embodiments, the resistivity ranges from 0.1 Ohm-centimeter to 40 Ohm-centimeter and remains substantially constant while applying an electrical field of up 8 mega-Volts/centimeter to the embedded resistor. The embedded resistor may be made from an amorphous material, and the material is operable to remain amorphous even when subjected to typical annealing conditions.

Abstract: Provided are methods of fabricating memory cells such as resistive random access memory (ReRAM) cells. A method involves forming a first layer including two high-k dielectric materials such that one material has a higher dielectric constant than the other material. In some embodiments, hafnium oxide and titanium oxide form the first layer. The higher-k material may be present at a lower concentration. In some embodiments, a concentration ratio of these two high-k materials is between about 3 and 7. The first layer may be formed using atomic layer deposition. The first layer is then annealed in an oxygen-containing environment. The method may proceed with forming a second layer including a low-k dielectric material, such as silicon oxide, and forming an electrode. After forming the electrode, the memory cell is annealed in a nitrogen containing environment. The nitrogen anneal may be performed at a higher temperature than the oxygen anneal.

Abstract: A method of fabricating a resistive random access memory (ReRAM) cell may include forming a set of nanolaminate structures over an electrode, such that each structure includes at least one first element oxide layer and at least one second element oxide layer. The overall set is operable as a resistive switching layer in a ReRAM cell. In this set, an average atomic ratio of the first element to the second element is different in at least two nanolaminate structures. This ratio may be less in nanolaminate structures that are closer to electrodes than in the middle nanolaminate structures. Alternatively, this ratio may increase from one end of the set to another. The first element may be less electronegative than the second elements. The first element may be hafnium, while the second element may be one of zirconium, aluminum, titanium, tantalum, or silicon.

Abstract: Provided are resistive random access memory (ReRAM) cells and methods of fabricating thereof. A ReRAM cell includes an embedded resistor and a resistive switching layer connected in series with this resistor. The resistor is configured to prevent over-programming of the cell by limiting electrical currents through the resistive switching layer. Unlike the resistive switching layer, which changes its resistance in order to store data, the embedded resistor maintains a substantially constant resistance during operation of the cell. The embedded resistor is formed from tantalum nitride and silicon nitride. The atomic ratio of tantalum and silicon may be specifically selected to yield resistors with desired densities and resistivities as well as ability to remain amorphous when subjected to various annealing conditions. The embedded resistor may also function as a diffusion barrier layer and prevent migration of components between one of the electrodes and the resistive switching layer.

Abstract: Provided are resistive random access memory (ReRAM) cells and methods of fabricating thereof. A ReRAM cell includes an embedded resistor and resistive switching layer connected in series. The embedded resistor prevents excessive electrical currents through the resistive switching layer, especially when the resistive switching layer is switched into its low resistive state, thereby preventing over-programming. The embedded resistor includes aluminum, nitrogen, and one or more additional metals (other than aluminum). The concentration of each component is controlled to achieve desired resistivity and stability of the embedded resistor. In some embodiments, the resistivity ranges from 0.1 Ohm-centimeter to 40 Ohm-centimeter and remains substantially constant while applying an electrical field of up 8 mega-Volts/centimeter to the embedded resistor. The embedded resistor may be made from an amorphous material, and the material is operable to remain amorphous even when subjected to typical annealing conditions.

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.