Abstract: Embodiments generally include a method of forming a nonvolatile memory device that contains a resistive switching memory element that has an improved device switching capacity by using multiple layers of variable resistance layers. In one embodiment, the resistive switching element comprises at least three layers of variable resistance materials to increase the number of logic states. Each variable resistance layer may have an associated high resistance state and an associated low resistance state. As the resistance of each variable resistance layer determines the digital data bit that is stored, the multiple variable resistance layers per memory element allows for additional data storage without the need to further increase the density of nonvolatile memory devices.

Abstract: A non-volatile memory device includes a plurality of pillars, where each of the plurality of pillars contains a non-volatile memory cell containing a steering element and a storage element and at least one of a top corner or a bottom corner of each of the plurality of pillars is rounded. A method of making non-volatile memory device includes forming a stack of device layers, and patterning the stack to form a plurality of pillars, where each of the plurality of pillars contains a non-volatile memory cell that contains a steering element and a storage element, and where at least one of top corner or bottom corner of each of the plurality of pillars is rounded.

Abstract: A monolithic three dimensional memory array is provided that includes a first memory level formed above a substrate, and a second memory level monolithically formed above the first memory level. The first memory level includes a first plurality of substantially parallel, substantially coplanar conductors extending in a first direction, a second plurality of substantially parallel, substantially coplanar conductors extending in a second direction, the second direction different from the first direction, the second conductors above the first conductors, and a first plurality of devices. Each of the first plurality of devices is disposed between one of the first conductors and one of the second conductors, and includes a resistivity-switching binary metal oxide or nitride compound and a silicon, germanium, or silicon-germanium alloy resistor of a single conductivity type. Numerous other aspects are provided.

Abstract: A three-dimensional array of memory elements reversibly change a level of electrical conductance/resistance in response to one or more voltage differences being applied across them. Memory elements are formed across a plurality of planes positioned different distances above a semiconductor substrate. Local bit lines to which the memory elements of all planes are connected are oriented vertically from the substrate and through the plurality of planes. Vertically oriented select devices are used to connect the local bit lines to global bit lines. A first subset of the vertically oriented select devices are positioned above the vertically oriented bit lines and a second subset of the vertically oriented select devices (interleaved with the first subset of the vertically oriented select devices) are positioned below the vertically oriented bit lines.

Abstract: Silicon nitride antifuses can be advantageously used in memory arrays employing diode-antifuse cells. Silicon nitride antifuses can be ruptured faster and at a lower breakdown field than antifuses formed of other materials, such as silicon dioxide. Examples are given of monolithic three dimensional memory arrays using silicon nitride antifuses with memory cells disposed in rail-stacks and pillars, and including PN and Schottky diodes. Pairing a silicon nitride antifuse with a low-density, high-resistivity conductor gives even better device performance.

Abstract: A storage system and method for forming a storage system that uses punch-through diodes as a steering element in series with a reversible resistivity-switching element is described. The punch-through diode allows bipolar operation of a cross-point memory array. The punch-through diode may have a symmetrical non-linear current/voltage relationship. The punch-through diode has a high current at high bias for selected cells and a low leakage current at low bias for unselected cells. Therefore, it is compatible with bipolar switching in cross-point memory arrays having resistive switching elements. The punch-through diode may be a N+/P?/N+ device or a P+/N?/P+ device.

Abstract: A memory array having memory cells comprising a diode and a phase change material is reliably programmed by maintaining all unselected memory cells in a reverse biased state. Thus leakage is low and assurance is high that no unselected memory cells are disturbed. In order to avoid disturbing unselected memory cells during sequential writing, previously selected word and bit lines are brought to their unselected voltages before new bit lines and word lines are selected. A modified current mirror structure controls state switching of the phase change material.

Abstract: Methods for operating a semiconductor memory array including dynamically adjusting control line voltages (e.g., unselected word line or unselected bit line voltages) based on one or more array conditions associated with the semiconductor memory array are described. The one or more array conditions may include a temperature associated with the semiconductor memory array or a particular number of write cycles associated with the semiconductor memory array. In some embodiments, an intermediate voltage is generated based on the one or more array conditions and applied to the unselected word lines and the unselected bit lines of the semiconductor memory array. The one or more intermediate voltages may be generated such that a first voltage difference across unselected memory cells sharing a selected word line is different from a second voltage difference across other unselected memory cells sharing a selected bit line based on the one or more array conditions.

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: In a first aspect, a memory cell is provided that includes (1) a first conductor; (2) a reversible resistance-switching element formed above the first conductor including (a) a carbon-based resistivity switching material; and (b) a carbon-based interface layer coupled to the carbon-based resistivity switching material; (3) a steering element formed above the first conductor; and (4) a second conductor formed above the reversible resistance-switching element and the steering element. Numerous other aspects are provided.

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

Abstract: Methods of programming two terminal memory cells are provided. A method includes: (a) reading information of a memory page including first, second, and nth memory cells, the information including first, second, and nth program pulse tuning instructions; (b) creating a first program pulse in accordance with the first program pulse tuning instructions to program the first memory cell; (c) locking the first memory cell from further programming pulses; (d) creating a second program pulse in accordance with the second program pulse tuning instructions to program the second memory cell; (e) locking the second memory cell from further programming pulses; and (f) creating an nth program pulse in accordance with the nth program pulse tuning instructions to program the nth memory cell.

Abstract: In some aspects, a method of fabricating a memory cell is provided that includes (1) fabricating a first conductor above a substrate; (2) selectively fabricating a carbon nano-tube (CNT) material above the first conductor; (3) fabricating a diode above the CNT material; and (4) fabricating a second conductor above the diode. Numerous other aspects are provided.

Abstract: A punch-through diode and method of fabricating the same are disclosed herein. The punch-through diode may be used as a steering element in a memory device having a reversible resistivity-switching element. For example, a memory cell may include a reversible resistivity-switching element in series with a punch-through diode. The punch-through diode allows bipolar operation of a cross-point memory array. The punch-through diode may have a symmetrical non-linear current/voltage relationship. The punch-through diode has a high current at high bias for selected cells and a low leakage current at low bias for unselected cells. In other words, the ratio of Ion/Ioff is high. Therefore, the punch-through diode is compatible with bipolar switching in cross-point memory arrays having resistive switching elements.

Abstract: Memory cells, and methods of forming such memory cells, are provided that include a carbon-based reversible resistivity switching material. In particular embodiments, methods in accordance with this invention form a memory cell by (a) depositing a layer of the carbon material above a substrate; (b) doping the deposited carbon layer with a dopant; (c) depositing a layer of the carbon material over the doped carbon layer; and (d) iteratively repeating steps (b) and (c) to form a stack of doped carbon layers having a desired thickness. Other aspects are also provided.

Abstract: Embodiments of the invention generally include a method of forming a nonvolatile memory device that contains a resistive switching memory element that has an improved device switching performance and lifetime, due to the addition of a current limiting component disposed therein. In one embodiment, the current limiting component comprises a resistive material that is configured to improve the switching performance and lifetime of the resistive switching memory element. The electrical properties of the current limiting layer are configured to lower the current flow through the variable resistance layer during the logic state programming steps (i.e., “set” and “reset” steps) by adding a fixed series resistance in the resistive switching memory element found in the nonvolatile memory device. In one embodiment, the current limiting component comprises a tunnel nitride that is a current limiting material that is disposed within a resistive switching memory element in a nonvolatile resistive switching memory device.

Abstract: A method of forming a reversible resistance-switching metal-insulator-metal structure is provided, the method including forming a first non-metallic conducting layer, forming a non-conducting layer above the first non-metallic conducting layer, forming a second non-metallic conducting layer above the non-conducting layer, etching the first non-metallic conducting layer, non-conducting layer and second non-metallic conducting layer to form a pillar, and disposing a carbon material layer about a sidewall of the pillar. Other aspects are also provided.

Abstract: Memory cells, and methods of forming such memory cells, are provided that include a steering element coupled to a carbon-based reversible resistivity switching material that has an increased resistivity, and a switching current that is less than a maximum current capability of the steering element used to control current flow through the carbon-based reversible resistivity switching material. In particular embodiments, methods and apparatus in accordance with this invention form a steering element, such as a diode, having a first width, coupled to a reversible resistivity switching material, such as aC, having a second width smaller than the first width.

Abstract: A three dimensional monolithic memory array of non-volatile storage elements includes a plurality of word lines and a plurality of bit lines. The plurality of bit lines are grouped into columns. One page of data is stored across multiple word lines by programming non-volatile storage elements connected to one column of bit lines and multiple word lines while maintaining the selection of the one column of bit lines. In one embodiment, programming non-volatile storage elements includes selectively connecting bit lines to sense amplifiers using selection circuits that include a storage device, a select circuit connected to the storage device and one or more level shifters providing two or more interfaces to the respective selection circuit.

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 having a metal oxide buffer layer disposed on or over a metal oxide bulk layer. The metal oxide bulk layer contains a metal-rich oxide material and the metal oxide buffer layer contains a metal-poor oxide material. The metal oxide bulk layer is less electrically resistive than the metal oxide buffer layer since the metal oxide bulk layer is less oxidized or more metallic than the metal oxide buffer layer. In one example, the metal oxide bulk layer contains a metal-rich hafnium oxide material and the metal oxide buffer layer contains a metal-poor zirconium oxide material.