Patents Assigned to Sandisk 3D LLC
  • Patent number: 8912524
    Abstract: 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 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 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 compared to the remainder of the resistive switching layer, and is formed during the resistive switching memory device's fabrication process.
    Type: Grant
    Filed: November 8, 2013
    Date of Patent: December 16, 2014
    Assignees: SanDisk 3D LLC, Kabushiki Kaisha Toshiba
    Inventors: Yun Wang, Tony Chiang, Imran Hashim
  • Patent number: 8913418
    Abstract: 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.
    Type: Grant
    Filed: May 10, 2013
    Date of Patent: December 16, 2014
    Assignees: Intermolecular, Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLC
    Inventors: Yun Wang, Vidyut Gopal, Chien-Lan Hsueh
  • Patent number: 8913413
    Abstract: The system includes multiple sets of local data lines in one or more routing metal layers below the three-dimensional memory array and multiple sets of global data lines in one or more top metal layers above the three-dimensional memory array. Each set of one or more blocks include one set of the local data lines. Each bay includes one set of global data lines that connect to the group of sense amplifiers associated with the blocks of the respective bay. Each block includes a subset of first selection circuits for selectively coupling a subset of array lines of the first type to respective local data lines. Each block includes a subset of second selection circuits for selectively coupling a subset of the respective local data lines to global data lines associated with a respective bay.
    Type: Grant
    Filed: January 31, 2012
    Date of Patent: December 16, 2014
    Assignee: SanDisk 3D LLC
    Inventors: Tianhong Yan, Luca Fasoli
  • Patent number: 8913417
    Abstract: A memory cell is provided that includes a steering element, a reversible resistance-switching element coupled to the steering element and a silicide-forming metal layer disposed between the steering element and the reversible resistance-switching element. The reversible resistance-switching element includes tantalum, and is formed using a selective deposition process. Numerous other aspects are provided.
    Type: Grant
    Filed: July 24, 2012
    Date of Patent: December 16, 2014
    Assignee: SanDisk 3D LLC
    Inventors: April Schricker, Brad Herner, Michael W. Konevecki
  • Patent number: 8906736
    Abstract: 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 ?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.
    Type: Grant
    Filed: September 8, 2014
    Date of Patent: December 9, 2014
    Assignees: Intermolecular, Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLC
    Inventors: Hieu Pham, Vidyut Gopal, Imran Hashim, Tim Minvielle, Dipankar Pramanik, Yun Wang, Takeshi Yamaguchi, Hong Sheng Yang
  • Publication number: 20140353566
    Abstract: A switching element for resistive-switching memory (ReRAM) provides a controllable, consistent filament break-point at an abrupt structural discontinuity between a layer of high-k high-ionicity variable-resistance (VR) material and a layer of low-k low-ionicity VR material. The high-ionicity layer may be crystalline and the low-ionicity layer may be amorphous. The consistent break-point and characteristics of the low-ionicity layer facilitate lower-power operation. The defects (e.g., oxygen or nitrogen vacancies) that constitute the filament originate either in the high-ionicity VR layer or in a source electrode. The electrode nearest to the low-ionicity layer may be intrinsically inert or may be rendered effectively inert. Some electrodes are rendered effectively inert by the creation of the low-ionicity layer over the electrode.
    Type: Application
    Filed: May 28, 2013
    Publication date: December 4, 2014
    Applicants: Intermolecular Inc., SanDisk 3D LLC, Kabushiki Kaisha Toshiba
    Inventors: Yun Wang, Tony P. Chiang, Dipankar Pramanik
  • Patent number: 8901530
    Abstract: Embodiments of the invention generally 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 one embodiment, the current limiting component comprises a tunnel oxide that is a current limiting material disposed within a resistive switching memory element in a nonvolatile resistive switching memory device.
    Type: Grant
    Filed: February 19, 2014
    Date of Patent: December 2, 2014
    Assignees: SanDisk 3D LLC, Kabushiki Kaisha Toshiba
    Inventors: Mihir Tendulkar, Imran Hashim, Yun Wang
  • Publication number: 20140347912
    Abstract: Methods for precharging bit lines using closed-loop feedback are described. In one embodiment, a sense amplifier may include a bit line precharge circuit for setting a bit line to a read voltage prior to sensing a memory cell connected to the bit line. The bit line precharge circuit may include a first transistor in a source-follower configuration with a first gate and a first source node electrically coupled to the bit line. By applying local feedback from the first source node to the first gate, the bit line settling time may be reduced. In some cases, a first voltage applied to the first gate may be determined based on a first current drawn from the first bit line. Thus, the first voltage applied to the first gate may vary over time depending on the conductivity of a selected memory cell connected to the bit line.
    Type: Application
    Filed: May 20, 2014
    Publication date: November 27, 2014
    Applicant: SANDISK 3D LLC
    Inventors: Chang Siau, Xiaowei Jiang, Yingchang Chen
  • Patent number: 8897056
    Abstract: A pillar-shaped memory cell is provided that includes a steering element, and a non-volatile state change element coupled in series with the steering element. Other aspects are also provided.
    Type: Grant
    Filed: July 29, 2013
    Date of Patent: November 25, 2014
    Assignee: SanDisk 3D LLC
    Inventors: Mark G. Johnson, Thomas H. Lee, Vivek Subramanian, Paul Michael Farmwald, James M. Cleeves
  • Patent number: 8895949
    Abstract: 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.
    Type: Grant
    Filed: February 10, 2014
    Date of Patent: November 25, 2014
    Assignees: SanDisk 3D LLC, Kabushiki Kaisha Toshiba
    Inventors: Mihir Tendulkar, Imran Hashim, Yun Wang
  • Patent number: 8897064
    Abstract: Methods for performing parallel voltage and current compensation during reading and/or writing of memory cells in a memory array are described. In some embodiments, the compensation may include adjusting a bit line voltage and/or bit line reference current applied to a memory cell based on a memory array zone, a bit line layer, and a memory cell direction associated with the memory cell. The compensation may include adjusting the bit line voltage and/or bit line reference current on a per memory cell basis depending on memory cell specific characteristics. In some embodiments, a read/write circuit for reading and/or writing a memory cell may select a bit line voltage from a plurality of bit line voltage options to be applied to the memory cell based on whether the memory cell has been characterized as a strong, weak, or typical memory cell.
    Type: Grant
    Filed: April 16, 2014
    Date of Patent: November 25, 2014
    Assignee: Sandisk 3D LLC
    Inventors: Yingchang Chen, Pankaj Kalra, Chandrasekhar Gorta
  • Patent number: 8895437
    Abstract: A 3D nonvolatile memory has memory elements arranged in a three-dimensional pattern defined by rectangular coordinates having x, y and z-directions and with a plurality of parallel planes stacked in the z-direction over a semiconductor substrate. It has vertical local bit lines and a plurality of staircase word lines. Each staircase word line has a series of alternating segments and risers elongated respectively in the x-direction and z-direction traversing across the plurality of planes in the z-direction with a segment in each plane. Methods of forming a slab of multi-plane memory with staircase word lines include processes with one masking and with two maskings for forming each plane.
    Type: Grant
    Filed: March 15, 2013
    Date of Patent: November 25, 2014
    Assignee: SanDisk 3D LLC
    Inventors: Raul Adrian Cernea, Henry Chien
  • Patent number: 8889492
    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.
    Type: Grant
    Filed: April 23, 2014
    Date of Patent: November 18, 2014
    Assignees: Intermolecular, Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLC
    Inventor: Tony P. Chiang
  • Patent number: 8890109
    Abstract: Provided are resistive random access memory (ReRAM) cells including resistive switching layers and thermally isolating structures for limiting heat dissipation from the switching layers during operation. Thermally isolating structures may be positioned within a stack or adjacent to the stack. For example, a stack may include one or two thermally isolating structures. A thermally isolating structure may directly interface with a switching layer or may be separated by, for example, an electrode. Thermally isolating structures may be formed from materials having a thermal conductivity of less than 1 W/m*K, such as porous silica and mesoporous titanium oxide. A thermally isolating structure positioned in series with a switching layer generally has a resistance less than the low resistance state of the switching layer. A thermally isolating structure positioned adjacent to a switching layer may have a resistance greater than the high resistance state of the switching layer.
    Type: Grant
    Filed: December 20, 2012
    Date of Patent: November 18, 2014
    Assignees: Intermolecular, Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLC
    Inventors: Yun Wang, Tony P. Chiang, Tim Minvielle, Takeshi Yamaguchi
  • Patent number: 8883655
    Abstract: 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.
    Type: Grant
    Filed: May 17, 2013
    Date of Patent: November 11, 2014
    Assignees: Intermoecular, Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLC
    Inventors: Yun Wang, Tony P. Chiang, Vidyut Gopal, Imran Hashim, Dipankar Pramanik
  • Patent number: 8885389
    Abstract: A three-dimensional array adapted for memory elements that reversibly change a level of electrical conductance in response to a voltage difference being applied across them. Memory elements are formed across a plurality of planes positioned different distances above a semiconductor substrate. Bit lines to which the memory elements of all planes are connected are oriented vertically from the substrate and through the plurality of planes.
    Type: Grant
    Filed: November 25, 2013
    Date of Patent: November 11, 2014
    Assignee: Sandisk 3D LLC
    Inventor: Roy E. Scheuerlein
  • Patent number: 8883557
    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.
    Type: Grant
    Filed: September 3, 2013
    Date of Patent: November 11, 2014
    Assignees: Intermolecular, Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLC
    Inventors: Chien-Lan Hsueh, Vidyut Gopal, Randall J. Higuchi, Takeshi Yamaguchi
  • Patent number: 8883569
    Abstract: A three-dimensional array adapted for memory elements that reversibly change a level of electrical conductance in response to a voltage difference being applied across them. Memory elements are formed across a plurality of planes positioned different distances above a semiconductor substrate. Bit lines to which the memory elements of all planes are connected are oriented vertically from the substrate and through the plurality of planes.
    Type: Grant
    Filed: November 25, 2013
    Date of Patent: November 11, 2014
    Assignee: Sandisk 3D LLC
    Inventor: Roy E. Scheuerlein
  • Patent number: 8885401
    Abstract: Methods for monitoring one or more load currents corresponding with one or more voltage regulators used during operation of a semiconductor memory are described. The one or more load currents may be due to the biasing of memory cells within a memory array or due to the presence of shorts between lines in the memory array. A plurality of load currents corresponding with a plurality of voltage regulators may be monitored in real-time before and during biasing of one or more memory arrays. The plurality of load currents may be monitored using a configurable load current monitoring circuit that uses a current summation technique. The ability to monitor the plurality of load currents before performing a programming operation on a memory array allows for remapping of defective portions of the memory array and modification of programming bandwidth prior to the programming operation.
    Type: Grant
    Filed: April 16, 2014
    Date of Patent: November 11, 2014
    Assignee: Sandisk 3D LLC
    Inventor: Vincent Lai
  • Patent number: 8883589
    Abstract: A method of forming a memory cell is provided, the method including forming a diode including a first region having a first conductivity type, counter-doping the diode to change the first region to a second conductivity type, and forming a memory element coupled in series with the diode. Other aspects are also provided.
    Type: Grant
    Filed: September 28, 2010
    Date of Patent: November 11, 2014
    Assignee: SanDisk 3D LLC
    Inventors: Xiying Costa, Abhijit Bandyopadhyay, Kun Hou, Brian Le, Yung-Tin Chen