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 Ω·cm, suitable for ReRAM embedded resistors, can be achieved. Some of the nanolaminates can function as combination embedded resistors and electrodes.
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 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:
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 translation:非易失性电阻性存储元件包括新型开关层及其形成方法。 开关层包括具有双稳电阻性质并通过将硅键合到氧或氮而形成的材料。 开关层可以包括SiO x,SiO x N y或SiN x中的至少一种。 有利地,在使用热退火工艺来形成诸如ReRAM器件的器件之后,SiO x,SiO x N y和SiN x通常保持非晶态。
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:
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:
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:
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 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.