| Patent application number | Description | Published |
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| 20090080406 | System and Method for Multicast and Broadcast Synchronization in Wireless Access Systems - In a method for multicast and broadcast synchronization a data payload frame is generated from a data payload. A frame number is assigned to the data payload frame, wherein the frame number includes a generating time of the data payload frame. The data payload frame is distributed to a plurality of base stations in a wireless access system. The offset spans a travel time of a data payload frame from the controller to the plurality of base stations as well as a scheduling time and a multiplexing time. | 03-26-2009 |
| 20090109893 | Cross-Layer Optimization of VoIP Services in Advanced Wireless Networks - A cross-layer optimization is presented between the MAC and Network layers to enhance the performance of VoIP services in advanced wireless networks. Among the factors considered in the optimization are the characteristics of the originating source and the network path. This information is relayed using the Network layer to provide feedback to the MAC layer in order to improve the end-to-end performance of VoIP services. | 04-30-2009 |
| 20110070883 | System and Method for Automatic Carrier Change Detection in a Wireless Communications System - A system and method for automatic carrier change detection in a wireless communications system are provided. A method for centralized carrier change detection includes detecting a carrier change in a carrier deployment of a cell, determining at least one inter-frequency neighbor cells of the cell, and updating the at least one inter-frequency neighbor cells regarding the carrier change. | 03-24-2011 |
| 20110070897 | System and Method for Deriving Cell Global Identity Information - A system and method for deriving cell global identity information are provided. A method for deriving cell global information includes receiving, at a first cell, a measurement report, determining a second identifier for the second cell based on a first identifier and information about the first cell, and adding the second cell to a cell list. The measurement report includes the first identifier of a second cell, and the second identifier is used to reference the second cell. | 03-24-2011 |
| 20120257494 | SIMULTANEOUS ACQUISITION OF A TD-SCDMA NETWORK IN CIRCUIT-SWITCHED FALLBACK FROM TDD-LTE SYSTEMS - In mobile user equipment (UE) configured to allow for operation on multiple wireless communication networks, such as on a TD-SCDMA network or on a TDD-LTE network, an improved method for handing over a circuit-switched call is offered. The proposed circuit-switched fallback procedure, employing an improved UE hardware architecture, allows for certain connection setup procedures to occur in parallel, such as the UE pre-acquiring the TD-SCDMA cell. The parallel operations thus speed up the circuit-switched fallback procedure and reduce existing delays in executing circuit-switched fallback from TDD-LTE to TD-SCDMA networks. | 10-11-2012 |
| 20120257550 | MEASUREMENT IN SIMULTANEOUS TDD-LTE AND TD-SCDMA/GSM SYSTEMS - In a mobile device for wireless communication capable of communicating on multiple radio access technologies (RATs), cell selection may be improved by reusing cell measurements for inter-RAT cell selection. This will reduce the number of cell measurements taken and improve mobile device performance. A time threshold may be used to instigate new cell measurement to prevent cell measurement data from being outdated. | 10-11-2012 |
| 20130250784 | INTER-SYSTEM CELL RESELECTION IN TD-SCDMA SYSTEMS - When a user equipment performs inter-cell measurement, it may desire to measure signal quality and signal level of a source radio access technology (RAT) cell and a target cell. The signal quality measurement may be Squal and the signal level measurement may be Srxlev. Because Squal is not defined for TD-SCDMA, a new measurement criteria is defined to allow proper comparison of source RAT cell measurements with target RAT cell measurements when a user equipment is considering switching to a target cell. | 09-26-2013 |
| 20130260736 | APPARATUS AND METHOD FOR SIGNALING NETWORK CAPABILITIES FOR A WIRELESS DEVICE - Methods and apparatus for wireless communication in a wireless communication network include maintaining a Public Land Mobile Network (PLMN) list and receiving an information request from a network, wherein the information request is associated with configuration parameters associated with the PLMN list. Aspects of the methods and apparatus configuring the UE based on the configuration parameters associated with the PLMN list. Aspects also include replying to the network that the UE is configured with the configuration parameters associated with the PLMN list. | 10-03-2013 |
| 20140378140 | METHOD AND APPARATUS FOR INTER RADIO ACCESS TECHNOLOGY (IRAT) CELL RESELECTION - The present disclosure presents a method and an apparatus for inter radio access technology (IRAT) cell reselection. For example, the method may include identifying that a user equipment (UE) in an idle or a discontinuous reception (DRX) mode is camped on a cell of a first RAT, determining that the cell the UE is camped on is not broadcasting any neighbor cell of a second RAT, scanning for one or more frequencies of the second RAT based on the determination, and triggering a cell reselection to a cell of the second RAT, wherein the cell of the second RAT is associated with a frequency identified during the scanning. As such, an autonomous IRAT cell reselection may be achieved. | 12-25-2014 |
| 20150094069 | ENHANCED INTER-RADIO ACCESS TECHNOLOGY HANDOVER PROCEDURES - In an aspect, methods and apparatus for handover in a communication network includes detecting a network entity handover condition to trigger handover from a source network entity of a first RAT. The methods and apparatus further include receiving a handover message from the source network entity of the first RAT including a list of target network entities. Additionally, the methods and apparatus include conducting handover to a target network entity selected from the list of target network entities. In another aspect, methods and apparatus for handover include receiving a handover request message from a UE at a source network entity of a first RAT. The methods and apparatus further include determining a list of target network entities in response to receiving the handover request message. Additionally, the methods and apparatus include transmitting a handover message including the list of target network entities from the source network entity to the UE. | 04-02-2015 |
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| 20090154215 | REDUCING NOISE AND DISTURBANCE BETWEEN MEMORY STORAGE ELEMENTS USING ANGLED WORDLINES - Devices and/or methods that facilitate reducing cross-talk noise and/or complementary bit disturb between adjacent storage elements in a memory device are presented. A memory device includes a memory array with wordlines formed in a zig-zag pattern such that each wordline can have segments that are parallel to the x-axis and other segments that are angled from a direction parallel to the x-axis based in part on a predetermined angle. Adjacent storage elements can be positioned at respective ends of an angled segment of a wordline to facilitate increasing the distance between such storage elements, as compared to the distance between storage elements associated with an orthogonal memory array, where the increase in distance can be based in part on the predetermined angle. The size of the memory array can be the same or substantially the same size, as compared to an orthogonal memory array. | 06-18-2009 |
| 20110186117 | THIN FILM SOLAR CELL WITH CERAMIC HANDLING LAYER - A method for fabricating a photovoltaic (PV) cell panel wherein all PV cells are formed simultaneously on a two-dimensional array of monocrystalline silicon mother wafers affixed to a susceptor is disclosed. Porous silicon separation layers are anodized in the surfaces of the mother wafers. The porous film is then smoothed to form a suitable surface for epitaxial film growth. An epitaxial reactor is used to grow n- and p-type films forming the PV cell structures. A glass/ceramic handling layer is then formed on the PV cell structures. The PV cell structures with handling layers are then exfoliated from the mother wafer. The array of mother wafers may be reused multiple times, thereby reducing materials costs for the completed solar panels. The glass/ceramic handling layers provide structural integrity to the thin epitaxial solar cells during the separation process and subsequent handling. | 08-04-2011 |
| 20130034947 | ATOMIC LAYER DEPOSITION OF METAL OXIDES FOR MEMORY APPLICATIONS - 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. | 02-07-2013 |
| 20130056702 | ATOMIC LAYER DEPOSITION OF METAL OXIDE MATERIALS FOR MEMORY APPLICATIONS - Embodiments of the invention generally relate to nonvolatile memory devices, such as a ReRAM cells, and methods for manufacturing such memory devices, which includes optimized, atomic layer deposition (ALD) processes for forming metal oxide film stacks. The metal oxide film stacks contain a metal oxide coupling layer disposed on a metal oxide host layer, each layer having different grain structures/sizes. The interface disposed between the metal oxide layers facilitates oxygen vacancy movement. In many examples, the interface is a misaligned grain interface containing numerous grain boundaries extending parallel to the electrode interfaces, in contrast to the grains in the bulk film extending perpendicular to the electrode interfaces. As a result, oxygen vacancies are trapped and released during switching without significant loss of vacancies. Therefore, the metal oxide film stacks have improved switching performance and reliability during memory cell applications compared to traditional hafnium oxide based stacks of previous memory cells. | 03-07-2013 |
| 20130065377 | INTERFACE LAYER IMPROVEMENTS FOR NONVOLATILE MEMORY APPLICATIONS - A resistive switching nonvolatile memory device having an interface layer disposed between a doped silicon electrode and a variable resistance layer fabricated in the nonvolatile memory device and methods of fabricating the same. In one embodiment, the interface layer is a high-k layer having a lower electrical EOT than native silicon oxide to act as a diffusion barrier between the variable resistance layer and the silicon electrode. Alternatively, the high-k interface layer may be formed by performing a nitrogen treatment on a fabricated silicon oxide layer. In another embodiment, the interface layer may be fabricated by performing a nitrogen or ozone treatment on the native oxide layer. In another embodiment, the interface layer is a fabricated silicon oxide layer resulting in an improved diffusion barrier between the variable resistance layer and the silicon electrode. In all embodiments, the interface layer also passivates the surface of the silicon electrode. | 03-14-2013 |
| 20130071984 | ATOMIC LAYER DEPOSITION OF HAFNIUM AND ZIRCONIUM OXIDES FOR MEMORY APPLICATIONS - 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. | 03-21-2013 |
| 20130107604 | Method for Forming Resistive Switching Memory Elements with Improved Switching Behavior | 05-02-2013 |
| 20130134376 | ATOMIC LAYER DEPOSITION OF ZIRCONIUM OXIDE FOR FORMING RESISTIVE-SWITCHING MATERIALS - Atomic layer deposition (ALD) can be used to form a dielectric layer of zirconium oxide for use in a variety of electronic devices. Forming the dielectric layer includes depositing zirconium oxide using atomic layer deposition. A method of atomic layer deposition to produce a metal-rich metal oxide comprises the steps of providing a silicon substrate in a reaction chamber, pulsing a zirconium precursor for a predetermined time to deposit a first layer, and oxidizing the first layer with water vapor to produce the metal-rich metal oxide. The metal-rich metal oxide has superior properties for non-volatile resistive-switching memories. | 05-30-2013 |
| 20130200323 | MULTIFUNCTIONAL ELECTRODE - 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 Ω 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. | 08-08-2013 |
| 20130200324 | Transition Metal Oxide Bilayers - 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 Å and about 100 Å, 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. | 08-08-2013 |
| 20130228735 | INTERFACIAL OXIDE USED AS SWITCHING LAYER IN A NONVOLATILE RESISTIVE MEMORY ELEMENT - A nonvolatile resistive memory element includes a host oxide formed from an interfacial oxide layer. The interfacial oxide layer is formed on the surface of a deposited electrode layer via in situ or post-deposition surface oxidation treatments. The switching performance of a resistive memory device based on such an interfacial oxide layer is equivalent or superior to the performance of a conventional resistive memory element. | 09-05-2013 |
| 20130334484 | Atomic Layer Deposition of Hafnium and Zirconium Oxides for Memory Applications - 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. | 12-19-2013 |
| 20130334490 | Transition Metal Oxide Bilayers - 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 Å and about 100 Å, 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. | 12-19-2013 |
| 20140014172 | Thin Film Solar Cell with Ceramic Handling Layer - A solar cell may comprise a stack of thin continuous epitaxial single crystal solar cell layers on a single crystal wafer, and a handling layer on the stack, the handling layer having a waffle-shaped structure with an array of either square or circular apertures, wherein the handling layer includes electrical contacts to the stack. The solar cell may comprise a boundary layer between the stack and the handling layer, the boundary layer being attached to both the stack and the handling layer, and the boundary layer being greater than 10 nanometers thick and parallel to the layers in the stack. The waffle-shaped structure may include perpendicular sets of first and second parallel ridges, wherein at least one of the sets is aligned at a small angle to a cleavage plane of the single crystal wafer. | 01-16-2014 |
| 20140038380 | Multifunctional Electrode - 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 Ωcm. 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. | 02-06-2014 |
| 20140073107 | Atomic Layer Deposition of Metal Oxide Materials for Memory Applications - Embodiments of the invention generally relate to nonvolatile memory devices, such as a ReRAM cells, and methods for manufacturing such memory devices, which includes optimized, atomic layer deposition (ALD) processes for forming metal oxide film stacks. The metal oxide film stacks contain a metal oxide coupling layer disposed on a metal oxide host layer, each layer having different grain structures/sizes. The interface disposed between the metal oxide layers facilitates oxygen vacancy movement. In many examples, the interface is a misaligned grain interface containing numerous grain boundaries extending parallel to the electrode interfaces, in contrast to the grains in the bulk film extending perpendicular to the electrode interfaces. As a result, oxygen vacancies are trapped and released during switching without significant loss of vacancies. Therefore, the metal oxide film stacks have improved switching performance and reliability during memory cell applications compared to traditional hafnium oxide based stacks of previous memory cells. | 03-13-2014 |
| 20140078808 | Embedded Nonvolatile Memory Elements Having Resistive Switching Characteristics - Provided are nonvolatile memory assemblies each including a resistive switching layer and current steering element. The steering element may be a transistor connected in series with the switching layer. Resistance control provided by the steering element allows using switching layers requiring low switching voltages and currents. Memory assemblies including such switching layers are easier to embed into integrated circuit chips having other low voltage components, such as logic and digital signal processing components, than, for example, flash memory requiring much higher switching voltages. In some embodiments, provided nonvolatile memory assemblies operate at switching voltages less than about 3.0V and corresponding currents less than 50 microamperes. A memory element may include a metal rich hafnium oxide disposed between a titanium nitride electrode and doped polysilicon electrode. One electrode may be connected to a drain or source of the transistor, while another electrode is connected to a signal line. | 03-20-2014 |
| 20140124725 | Resistive Random Access Memory Cells Having Doped Current Limiting layers - Provided are semiconductor devices, such as resistive random access memory (ReRAM) cells, that include current limiting layers formed from doped metal oxides and/or nitrides. 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 annealing. In some embodiments, the breakdown voltage of a current limiting layer may be at least about 8V. Some examples of such current limiting layers include titanium oxide doped with niobium, tin oxide doped with antimony, and zinc oxide doped with aluminum. Dopants and base materials may be deposited as separate sub-layers and then redistributed by annealing or may be co-deposited using reactive sputtering or co-sputtering. The high resistivity of the layers allows scaling down the size of the semiconductor devices including these layer while maintaining their performance. | 05-08-2014 |
| 20140154859 | Methods and Vehicles for High Productivity Combinatorial Testing of Materials for Resistive Random Access Memory Cells - Provided are methods for processing different materials on the same substrate for high throughput screening of multiple ReRAM materials. A substrate may be divided into multiple site isolated regions, each region including one or more base structures operable as bottom electrodes of ReRAM cells. Different test samples may be formed over these base structures in a combinatorial manner. Specifically, each site isolated region may receive a test sample that has a different characteristic than at least one other sample provided in another region. The test samples may have different compositions and/or thicknesses or be deposited using different techniques. These different samples are then etched in the same operation to form portions of the samples. Each portion is substantially larger than the corresponding base structure and fully covers this base structure to protect the interface between the base structure and the portion during etching. | 06-05-2014 |
| 20140175360 | Bilayered Oxide Structures for ReRAM Cells - Provided are resistive random access memory (ReRAM) cells having bi-layered metal oxide structures. The layers of a bi-layered structure may have different compositions and thicknesses. Specifically, one layer may be thinner than the other layer, sometimes as much as 5 to 20 times thinner. The thinner layer may be less than 30 Angstroms thick or even less than 10 Angstroms thick. The thinner layer is generally more oxygen rich than the thicker layer. Oxygen deficiency of the thinner layer may be less than 5 atomic percent or even less than 2 atomic percent. In some embodiments, a highest oxidation state metal oxide may be used to form a thinner layer. The thinner layer typically directly interfaces with one of the electrodes, such as an electrode made from doped polysilicon. Combining these specifically configured layers into the bi-layered structure allows improving forming and operating characteristics of ReRAM cells. | 06-26-2014 |
| 20140175367 | Materials for Thin Resisive Switching Layers of Re-RAM Cells - Provided are resistive random access memory (ReRAM) cells that include thin resistive switching layers. In some embodiments, the resistive switching layers have a thickness of less than about 50 Angstroms and even less than about 30 Angstroms. The resistive switching characteristics of such thin layers are maintained by controlling their compositions and using particular fabrication techniques. Specifically, low oxygen vacancy metal oxides, such as tantalum oxide, may be used. The concentration of oxygen vacancies may be less than 5 atomic percent. In some embodiments, the resistive switching layers also include nitrogen and. For example, compositions of some specific resistive switching layers may be represented by Ta | 06-26-2014 |
| 20140217348 | Transition Metal Oxide Bilayers - 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 Å and about 100 Å, 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. | 08-07-2014 |
| 20140264231 | Confined Defect Profiling within Resistive Random Memory Access Cells - Provided are resistive random access memory (ReRAM) cells and methods of fabricating thereof. A stack including a defect source layer, a defect blocking layer, and a defect acceptor layer disposed between the defect source layer and the defect blocking layer may be subjected to annealing. During the annealing, defects are transferred in a controllable manner from the defect source layer to the defect acceptor layer. At the same time, the defects are not transferred into the defect blocking layer thereby creating a lowest concentration zone within the defect acceptor layer. This zone is responsible for resistive switching. The precise control over the size of the zone and the defect concentration within the zone allows substantially improvement of resistive switching characteristics of the ReRAM cell. In some embodiments, the defect source layer includes aluminum oxynitride, the defect blocking layer includes titanium nitride, and the defect acceptor layer includes aluminum oxide. | 09-18-2014 |
| 20140363920 | Atomic Layer Deposition of Metal Oxides for Memory Applications - 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. | 12-11-2014 |
| 20140374240 | MULTIFUNCTIONAL ELECTRODE - 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 10Ω 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. | 12-25-2014 |
| 20150034898 | Confined Defect Profiling within Resistive Random Memory Access Cells - Provided are resistive random access memory (ReRAM) cells and methods of fabricating thereof. A stack including a defect source layer, a defect blocking layer, and a defect acceptor layer disposed between the defect source layer and the defect blocking layer may be subjected to annealing. During the annealing, defects are transferred in a controllable manner from the defect source layer to the defect acceptor layer. At the same time, the defects are not transferred into the defect blocking layer thereby creating a lowest concentration zone within the defect acceptor layer. This zone is responsible for resistive switching. The precise control over the size of the zone and the defect concentration within the zone allows substantially improvement of resistive switching characteristics of the ReRAM cell. In some embodiments, the defect source layer includes aluminum oxynitride, the defect blocking layer includes titanium nitride, and the defect acceptor layer includes aluminum oxide. | 02-05-2015 |
| 20150056749 | Atomic Layer Deposition of Metal Oxide Materials for Memory Applications - Embodiments of the invention generally relate to nonvolatile memory devices, such as a ReRAM cells, and methods for manufacturing such memory devices, which includes optimized, atomic layer deposition (ALD) processes for forming metal oxide film stacks. The metal oxide film stacks contain a metal oxide coupling layer disposed on a metal oxide host layer, each layer having different grain structures/sizes. The interface disposed between the metal oxide layers facilitates oxygen vacancy movement. In many examples, the interface is a misaligned grain interface containing numerous grain boundaries extending parallel to the electrode interfaces, in contrast to the grains in the bulk film extending perpendicular to the electrode interfaces. As a result, oxygen vacancies are trapped and released during switching without significant loss of vacancies. Therefore, the metal oxide film stacks have improved switching performance and reliability during memory cell applications compared to traditional hafnium oxide based stacks of previous memory cells. | 02-26-2015 |
| 20150060753 | CONTROLLING COMPOSITION OF MULTIPLE OXIDES IN RESISTIVE SWITCHING LAYERS USING ATOMIC LAYER DEPOSITION - 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. | 03-05-2015 |
