Patents Assigned to Sandisk 3D LLC
  • Patent number: 8885428
    Abstract: Methods for reducing variability in bias voltages applied to a plurality of memory cells during a sensing operation caused by IR drops along a word line shared by the plurality of memory cells are described. In some embodiments, IR drops along a shared word line may be reduced by reducing sensing currents associated with memory cells whose state has already been determined during a sensing operation. In one example, once a sense amplifier detects that a memory cell being sensed is in a particular state, then the sense amplifier may disable sensing of the memory cell and discharge a corresponding bit line associated with the memory cell. In some cases, a bit line voltage associated with a memory cell whose state has not already been determined during a first phase of a sensing operation may be increased during a second phase of the sensing operation.
    Type: Grant
    Filed: February 22, 2013
    Date of Patent: November 11, 2014
    Assignee: Sandisk 3D LLC
    Inventors: Yingchang Chen, Jeffrey Koon Yee Lee
  • Patent number: 8885400
    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: February 21, 2013
    Date of Patent: November 11, 2014
    Assignee: SanDisk 3D LLC
    Inventors: Yingchang Chen, Pankaj Kalra, Chandrasekhar Gorla
  • Patent number: 8885381
    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: December 12, 2011
    Date of Patent: November 11, 2014
    Assignee: Sandisk 3D LLC
    Inventor: Roy E. Scheuerlein
  • Patent number: 8878235
    Abstract: In some aspects, a method of fabricating a memory cell is provided that includes fabricating a steering element above a substrate, and fabricating a reversible-resistance switching element coupled to the steering element by selectively fabricating carbon nano-tube (“CNT”) material above the substrate, wherein the CNT material comprises a single CNT. Numerous other aspects are provided.
    Type: Grant
    Filed: September 18, 2011
    Date of Patent: November 4, 2014
    Assignee: SanDisk 3D LLC
    Inventors: April D. Schricker, Wu-Yi Chien, Kun Hou, Raghuveer S. Makala, Jingyan Zhang, Yibo Nian
  • Patent number: 8878152
    Abstract: A nonvolatile resistive memory element includes one or more novel oxygen isolation structures that protect the resistive switching material of the memory element from oxygen migration. One such oxygen isolation structure comprises an oxygen barrier layer that isolates the resistive switching material from other portions of the resistive memory device during fabrication and/or operation of the memory device. Another such oxygen isolation structure comprises a sacrificial layer that reacts with unwanted oxygen migrating toward the resistive switching material during fabrication and/or operation of the memory device.
    Type: Grant
    Filed: February 29, 2012
    Date of Patent: November 4, 2014
    Assignees: Intermolecular, Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLC
    Inventors: Yun Wang, Tony P. Chiang, Imran Hashim, Dipankar Pramanik
  • Patent number: 8877586
    Abstract: A process for forming reversible resistance-switching memory cells having resistance-switching nano-particles which provide a reduced contact area to top and bottom electrodes of the memory cells, thereby limiting a peak current. Recesses are formed in a layered semiconductor material above the bottom electrodes, and one or more coatings of nano-particles are applied. The nano-particles self-assemble in the recesses so that they are positioned in a controlled manner. A top electrode material is then deposited. In one approach, the recesses are formed by spaced-apart trenches, and the nano-particles self-assemble along the spaced-apart trenches. In another approach, the recesses for each resistance-switching memory cell are separate from one another, and the resistance-switching memory cells are pillar-shaped. The coatings can be provided in one layer, or in multiple layers which are separated by an insulation layer.
    Type: Grant
    Filed: January 31, 2013
    Date of Patent: November 4, 2014
    Assignee: SanDisk 3D LLC
    Inventors: James K Kai, Takashi W Orimoto, Vinod R Purayath, George Matamis
  • Patent number: 8879299
    Abstract: A non-volatile memory cell includes a first electrode, a steering element, a metal oxide storage element located in series with the steering element, a dielectric resistor located in series with the steering element and the metal oxide storage element, and a second electrode.
    Type: Grant
    Filed: July 18, 2012
    Date of Patent: November 4, 2014
    Assignee: Sandisk 3D LLC
    Inventors: Kun Hou, Yung-Tin Chen, Zhida Lan, Huiwen Xu
  • Patent number: 8872152
    Abstract: A nonvolatile memory device that contains a resistive switching memory element with improved device switching performance and lifetime, and methods of forming the same. A nonvolatile memory element includes a first electrode layer formed on a substrate, a resistive switching layer formed on the first electrode layer, and a second electrode layer. The resistive switching layer comprises a metal oxide and is disposed between the first electrode layer and the second electrode layer. The elemental metal selected for each of the first and second electrode layers is the same metal as selected to form the metal oxide resistive switching layer. The use of common metal materials within the memory element eliminates the growth of unwanted and incompatible native oxide interfacial layers that create undesirable circuit impedance.
    Type: Grant
    Filed: December 13, 2012
    Date of Patent: October 28, 2014
    Assignees: Intermolecular, Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLC
    Inventors: Federico Nardi, Yun Wang
  • Patent number: 8866124
    Abstract: In a first aspect, a vertical semiconductor diode is provided that includes (1) a first semiconductor layer formed above a substrate; (2) a second semiconductor layer formed above the first semiconductor layer; (3) a first native oxide layer formed above the first semiconductor layer; and (4) a third semiconductor layer formed above the first semiconductor layer, second semiconductor layer and first native oxide layer so as to form the vertical semiconductor diode that includes the first native oxide layer. Numerous other aspects are provided.
    Type: Grant
    Filed: February 2, 2011
    Date of Patent: October 21, 2014
    Assignee: SanDisk 3D LLC
    Inventors: Steven Maxwell, Abhijit Bandyopadhyay, Kun Hou, Er-Xuan Ping, Yung-Tin Chen, Li Xiao
  • Patent number: 8866118
    Abstract: A nonvolatile memory device contains a resistive switching memory element with improved device switching performance and life and methods for forming the same. The nonvolatile memory device has a first layer on a substrate, a resistive switching layer on the first layer, and a second layer. The resistive switching layer is disposed between the first layer and the second layer and the resistive switching layer comprises a material having the same morphology as the top surface of the first layer. A method of forming a nonvolatile memory element in a ReRAM device includes forming a resistive switching layer on a first layer and forming a second layer, so that the resistive switching layer is disposed between the first layer and the second layer. The resistive switching layer comprises a material formed with the same morphology as the top surface of the first layer.
    Type: Grant
    Filed: December 21, 2012
    Date of Patent: October 21, 2014
    Assignees: Intermolecular, Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLC
    Inventors: Federico Nardi, Yun Wang
  • Patent number: 8866121
    Abstract: 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.
    Type: Grant
    Filed: February 17, 2012
    Date of Patent: October 21, 2014
    Assignees: SanDisk 3D LLC, Kabushiki Kaisha Toshiba
    Inventors: Yun Wang, Tony P. Chiang, Imran Hashim
  • Patent number: 8859328
    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: April 16, 2014
    Date of Patent: October 14, 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
  • Patent number: 8861258
    Abstract: A resistance-switching memory cell is programmed in a set or reset operation which tests the stability of the cell. A first programming phase using program voltages which increase in magnitude or duration until a program verify test is passed. A stability test phase is then performed to evaluate a stability of the memory cell. The stability test phase determines whether the memory cell is weak and likely to transition out of the set or reset state by applying one or more disturb pulses and performing one or more stability verify tests. The disturb pulses can have a reduced magnitude or duration compared to the program voltages. If the stability test phase indicates the memory cell is not stable, a second programming phase is performed. If the stability test phase indicates the memory cell is stable, the operation is concluded.
    Type: Grant
    Filed: February 21, 2013
    Date of Patent: October 14, 2014
    Assignee: SanDisk 3D LLC
    Inventors: Zhida Lan, Roy E Scheuerlein, Thomas Yan
  • Patent number: 8860501
    Abstract: A charge pump system includes a charge pump that receives its clock signals, generated by an oscillator circuit, though a clock buffer. The clock buffer is power-controlled to reduce power consumption and output voltage ripple. The buffer is formed of a series of inverter that are connected to the power supply level through a clamping element, such as a transistor whose gate is controlled by a regulation signal based on feedback from the pump's output.
    Type: Grant
    Filed: April 22, 2014
    Date of Patent: October 14, 2014
    Assignee: SanDisk 3D LLC
    Inventors: Kesheng Wang, Ali Al-Shamma
  • Patent number: 8860002
    Abstract: Provided are ReRAM cells, each having at least one interface between an electrode and a resistive switching layers with a maximum field value of less than 0.25. The electrode materials forming such interfaces include tantalum nitrides doped with lanthanum, aluminum, erbium yttrium, or terbium (e.g., TaX(Dopant)YN, where X is at least about 0.95). The electrode materials have low work functions (e.g., less than about 4.5 eV). At the same time, the resistive switching materials have high relative dielectric permittivities (e.g., greater than about 30) and high electron affinities (greater than about for 3.5 eV). Niobium oxide is one example of a suitable resistive switching material. Another electrode interfacing the resistive switching layer may have different characteristics and, in some embodiments, may be an inert electrode.
    Type: Grant
    Filed: December 20, 2012
    Date of Patent: October 14, 2014
    Assignees: Intermolecular, Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLC
    Inventors: Mihir Tendulkar, Imran Hashim, Tim Minvielle, Yun Wang, Takeshi Yamaguchi
  • Publication number: 20140299834
    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.
    Type: Application
    Filed: May 27, 2014
    Publication date: October 9, 2014
    Applicants: Intermolecular Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLC
    Inventors: Dipankar Pramanik, Tony P. Chiang, Mankoo Lee
  • Publication number: 20140301131
    Abstract: Methods for forming non-volatile storage elements in a non-volatile storage system are described. In some embodiments, during a forming operation, a cross-point memory array may be biased such that waste currents are minimized or eliminated. In one example, the memory array may be biased such that a first word line comb is set to a first voltage, a second word line comb interdigitated with the first word line comb is set to the first voltage, and selected vertical bit lines are set to a second voltage such that a forming voltage is applied across non-volatile storage elements to be formed. In some embodiments, a memory array may include a plurality of word line comb layers and a forming operation may be concurrently performed on non-volatile storage elements on all of the plurality of word line comb layers or a subset of the plurality of word line comb layers.
    Type: Application
    Filed: April 5, 2014
    Publication date: October 9, 2014
    Applicant: SanDisk 3D LLC
    Inventors: Chang Siau, Tianhong Yan
  • Publication number: 20140301130
    Abstract: Methods for forming non-volatile storage elements in a non-volatile storage system are described. In some embodiments, a plurality of forming operations may be performed in which non-volatile storage elements located near the far end of a plurality of word line fingers associated with a word line comb are formed prior to forming other non-volatile storage elements. In one example, non-volatile storage elements may be formed in each of the plurality of word line fingers in parallel and in an order that forms non-volatile storage elements in each of the plurality of word line fingers that are located near the far ends of the plurality of word line fingers before forming other non-volatile storage elements. Each non-volatile storage element that is formed during a forming operation may be current limited while a forming voltage is applied across the non-volatile storage element.
    Type: Application
    Filed: April 5, 2014
    Publication date: October 9, 2014
    Applicant: SanDisk 3D LLC
    Inventors: Chang Siau, Tianhong Yan
  • Patent number: 8853661
    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.
    Type: Grant
    Filed: March 15, 2013
    Date of Patent: October 7, 2014
    Assignees: Intermolecular, Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLC
    Inventors: Mihir Tendulkar, Randall J. Higuchi, Chien-Lan Hsueh
  • Patent number: 8853099
    Abstract: A nonvolatile resistive memory element has a novel variable resistance layer that includes a metal nitride, a metal oxide-nitride, a two-metal oxide-nitride, or a multilayer stack thereof. One method of forming the novel variable resistance layer comprises an interlayer deposition procedure, in which metal oxide layers are interspersed with metal nitride layers and then converted into a substantially homogeneous layer by an anneal process. Another method of forming the novel variable resistance layer comprises an intralayer deposition procedure, in which various ALD processes are sequentially interleaved to form a metal oxide-nitride layer. Alternatively, a metal oxide is deposited, nitridized, and annealed to form the variable resistance layer or a metal nitride is deposited, oxidized, and annealed to form the variable resistance layer.
    Type: Grant
    Filed: December 16, 2011
    Date of Patent: October 7, 2014
    Assignees: Intermolecular, Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLC
    Inventors: Yun Wang, Tony P. Chiang, Imran Hashim, Tim Minvielle, Takeshi Yamaguchi