132 results about "Resistive switching memory" patented technology

Embodiments of the invention include a method of forming a nonvolatile memory device that contains a resistive switching memory element that has improved device switching performance and lifetime, due to the addition of a current limiting component disposed therein. The electrical properties of the current limiting component are configured to lower the current flow through the variable resistance layer during the logic state programming steps by adding a fixed series resistance in the resistive switching memory element of the nonvolatile memory device. In some embodiments, the current limiting component comprises a varistor that is a current limiting material disposed within a resistive switching memory element in a nonvolatile resistive switching memory device. Typically, resistive switching memory elements may be formed as part of a high-capacity nonvolatile memory integrated circuit, which can be used in various electronic devices, such as digital cameras, mobile telephones, handheld computers, and music players.

A non-volatile resistive switching memory that includes a homogeneous material which changes between the insulative and conductive states due to correlations between electrons, particularly via a Mott transition. The material is crystallized into the conductive state and does not require electroforming.

A non-volatile resistive switching memory that includes a homogeneous material which changes between the insulative and conductive states due to correlations between electrons, particularly via a Mott transition. The material is crystallized into the conductive state and does not require electroforming.

Non-volatile resistive-switching memories are described, including a memory element having a first electrode, a second electrode, a metal oxide between the first electrode and the second electrode. The metal oxide switches using bulk-mediated switching, has a bandgap greater than 4 electron volts (eV), has a set voltage for a set operation of at least one volt per one hundred angstroms of a thickness of the metal oxide, and has a leakage current density less than 40 amps per square centimeter (A / cm2) measured at 0.5 volts (V) per twenty angstroms of the thickness of the metal oxide.

Resistive-switching memory elements having improved switching characteristics are described, including a memory element having a first electrode and a second electrode, a switching layer between the first electrode and the second electrode comprising hafnium oxide and having a first thickness, and a coupling layer between the switching layer and the second electrode, the coupling layer comprising a material including metal titanium and having a second thickness that is less than 25 percent of the first thickness.

A current-limiting layer and a current-reducing layer are incorporated into a resistive switching memory device to form memory arrays. The incorporated current-limiting layer reduces the occurrence of current spikes during the programming of the resistive switching memory device and the incorporated current-reducing layer minimizes the overall current levels that can flow through the resistive switching memory device. Together, the two incorporated layers help improve device performance and lifetime.

Resistive switching nonvolatile memory elements are provided. A metal-containing layer and an oxide layer for a memory element can be heated using rapid thermal annealing techniques. During heating, the oxide layer may decompose and react with the metal-containing layer. Oxygen from the decomposing oxide layer may form a metal oxide with metal from the metal-containing layer. The resulting metal oxide may exhibit resistive switching for the resistive switching memory elements.

Confinment techniques for non-volatile resistive-switching memories are described, including a memory element having a first electrode, a second electrode, a metal oxide between the first electrode and the second electrode. A resistive switching memory element described herein includes a first electrode adjacent to an interlayer dielectric, a spacer over at least a portion of the interlayer dielectric and over a portion of the first electrode and a metal oxide layer over the spacer and the first electrode such that an interface between the metal oxide layer and the electrode is smaller than a top surface of the electrode.

A method for forming a vertically stacked memory device. The method includes providing a semiconductor substrate having a surface region and forming a first dielectric material overlying the surface region. A first plurality of memory cells are formed overlying the first dielectric material. Each of the first plurality of memory cells includes at least a first top metal wiring structure spatially extending in a first direction, a first bottom wiring structure spatially extending in a second direction orthogonal to the first top metal wiring structure, and a first switching element sandwiched in an intersection region between the first top metal wiring structure and the first bottom metal wiring structure. In a specific embodiment, the method forms a thickness of second dielectric material overlying the first plurality of memory. A second plurality of memory cells are formed overlying the second dielectric material. Each of the second plurality of memory cells includes at least a second top metal wiring structure extending in the first direction, a second bottom wiring structure arranged spatially orthogonal to the second top metal wiring structure, and a second switching element sandwiched in an intersection region of the second top metal wiring structure and the second bottom metal wiring structure.

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. Typically, resistive switching memory elements may be formed as part of a high-capacity nonvolatile memory integrated circuit, which can be used in various electronic devices, such as digital cameras, mobile telephones, handheld computers, and music players.

According to various embodiments, a resistive-switching memory element and memory element array that uses a bipolar switching includes a select element comprising only a single diode that is not a Zener diode. The resistive-switching memory elements described herein can switch even when a switching voltage less than the breakdown voltage of the diode is applied in the reverse-bias direction of the diode. The memory elements are able to switch during the very brief period when a transient pulse voltage is visible to the memory element, and therefore can use a single diode per memory cell.

A non-volatile resistive switching memory that includes a material which changes between the insulative and conductive states. The material is stabilized against charge trapping by oxygen vacancies by an extrinsic ligand, such as carbon.

A resistive switching memory element including a doped silicon electrode is described, including a first electrode comprising doped silicon having a first work function, a second electrode having a second work function that is different from the first work function by between 0.1 and 1.0 electron volts (eV), a metal oxide layer between the first electrode and the second electrode, the metal oxide layer switches using bulk-mediated switching and has a bandgap of greater than 4 eV, and the memory element switches from a low resistance state to a high resistance state and vice versa.

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 at least one layer of resistive material that is configured to improve the switching performance and lifetime of the formed resistive switching memory element. The electrical properties of the formed current limiting layer, or resistive 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 formed resistive switching memory element found in the nonvolatile memory device.

A non-volatile resistive switching memory that includes a material which changes between the insulative and conductive states due to correlations between electrons, particularly via a Mott transition.The material is crystallized into the conductive state and does not require electroforming.

According to various embodiments, a resistive-switching memory element and memory element array that uses a bipolar switching includes a select element comprising only a single diode that is not a Zener diode. The resistive-switching memory elements described herein can switch even when a switching voltage less than the breakdown voltage of the diode is applied in the reverse-bias direction of the diode. The memory elements are able to switch during the very brief period when a transient pulse voltage is visible to the memory element, and therefore can use a single diode per memory cell.

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.

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.

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.

ALD processing techniques for forming non-volatile resistive-switching memories are described. In one embodiment, a method includes forming a first electrode on a substrate, maintaining a pedestal temperature for an atomic layer deposition (ALD) process of less than 100° Celsius, forming at least one metal oxide layer over the first electrode, wherein the forming the at least one metal oxide layer is performed using the ALD process using a purge duration of less than 20 seconds, and forming a second electrode over the at least one metal oxide layer.

Resistive-switching memory elements having improved switching characteristics are described, including a memory element having a first electrode and a second electrode, a switching layer between the first electrode and the second electrode comprising hafnium oxide and having a first thickness, and a coupling layer between the switching layer and the second electrode, the coupling layer comprising a material including metal titanium and having a second thickness that is less than 25 percent of the first thickness.

Embodiments of the present invention generally relate to a resistive switching nonvolatile memory element that is formed in a resistive switching memory device that may be used in a memory array to store digital data. The memory element is generally constructed as a metal-insulator-metal stack. The resistive switching portion of the memory element includes a getter portion and / or a defect portion. In general, the getter portion is an area of the memory element that is used to help form, during the resistive switching memory device's fabrication process, a region of the resistive switching layer that has a greater number of vacancies or defects as compared to the remainder of resistive switching layer. The defect portion is an area of the memory element that has a greater number of vacancies or defects as compared to the remainder of the resistive switching layer, and is formed during the resistive switching memory device's fabrication process. The addition of the getter or defect portions in a formed memory device generally improves the reliability of the resistive switching memory device, improves the switching characteristics of the formed memory device and can eliminate or reduce the need for the time consuming additional post fabrication “burn-in” or pre-programming steps.

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.

Cross point memory arrays with CBRAM and RRAM stacks are presented. A cross point memory array includes a first group of substantially parallel conductive lines and a second group of substantially parallel conductive lines, oriented substantially perpendicular to the first group of substantially parallel conductive lines. An array of memory stack is located at the intersections of the first group of substantially parallel conductive lines and the second group of substantially parallel conductive lines, wherein each memory stack comprises a conductive bridge memory element in series with a resistive-switching memory element.

A resistive switching non-volatile memory element is disclosed comprising a resistive switching metal-oxide layer sandwiched between and in contact with a top electrode and a bottom electrode, the resistive switching metal oxide layer having a substantial isotropic non-stoichiometric metal-to-oxygen ratio. For example, the memory element may comprise a nickel oxide resistive switching layer sandwiched between and in contact with a nickel top electrode and a nickel bottom electrode whereby the ratio oxygen-to-nickel of the nickel oxide layer is between 0 and 0.85.

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.