Patents Assigned to Sandisk 3D LLC
  • Patent number: 8625322
    Abstract: A three-dimensional array read/write (R/W) memory elements is formed across multiple layers of planes positioned at different distances above a semiconductor substrate. It is preferable to operate the R/W elements with low current and high resistive states. The resistance of these resistive states depends also on the dimension of the R/W elements and is predetermined by the process technology. A sheet electrode in series with the R/W element and a method of forming it provide another degree of freedom to adjust the resistance of the R/W memory element. The thickness of the sheet electrode is adjusted to obtain a reduced cross-sectional contact in the circuit path from the word line to the bit line. This allows the R/W memory element to have a much increased resistance and therefore to operate with much reduced currents. The sheet electrode is formed with little increase in cell size.
    Type: Grant
    Filed: December 12, 2011
    Date of Patent: January 7, 2014
    Assignee: SanDisk 3D LLC
    Inventors: George Samachisa, Johann Alsmeier
  • Patent number: 8618525
    Abstract: Embodiments of the invention generally relate to a resistive switching nonvolatile memory device having an interface layer structure disposed between at least one of the electrodes and a variable resistance layer formed in the nonvolatile memory device, and a method of forming the same. 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. In one configuration of the resistive switching nonvolatile memory device, the interface layer structure comprises a passivation region, an interface coupling region, and/or a variable resistance layer interface region that are configured to adjust the nonvolatile memory device's performance, such as lowering the formed device's switching currents and reducing the device's forming voltage, and reducing the performance variation from one formed device to another.
    Type: Grant
    Filed: June 9, 2011
    Date of Patent: December 31, 2013
    Assignees: Intermolecular, Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLC
    Inventors: Yun Wang, Tony Chiang, Imran Hashim
  • Patent number: 8619453
    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: December 31, 2013
    Assignee: Sandisk 3D LLC
    Inventor: Roy E. Scheuerlein
  • Patent number: 8618614
    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: December 31, 2013
    Assignee: Sandisk 3D LLC
    Inventor: Roy E. Scheuerlein
  • Publication number: 20130337606
    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.
    Type: Application
    Filed: August 20, 2013
    Publication date: December 19, 2013
    Applicants: Intermolecular Inc., SanDisk 3D LLC, Kabushiki Kaisha Toshiba
    Inventors: Mihir Tendulkar, Tim Minvielle, Yun Wang, Takeshi Yamaguchi
  • Publication number: 20130336036
    Abstract: In a 3D memory with vertical local bit lines, each local bit line is switchably connected to a node on a global bit line having first and second ends, the local bit line voltage is maintained at a predetermined reference level in spite of being driven by a bit line driver from a first end of the global bit line that constitutes variable circuit path length and circuit serial resistance. This is accomplished by a feedback voltage regulator comprising a voltage clamp at the first end of the global bit line controlled by a bit line voltage comparator at the second end of the global bit line. The comparator compares the bit line voltage sensed from the second end with the predetermined reference level and outputs a control voltage to control the voltage clamp In this way the voltage at the local bit line is regulated at the reference voltage.
    Type: Application
    Filed: March 11, 2013
    Publication date: December 19, 2013
    Applicant: SanDisk 3D LLC
    Inventor: Raul Adrian Cernea
  • Publication number: 20130334490
    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.
    Type: Application
    Filed: August 20, 2013
    Publication date: December 19, 2013
    Applicants: Intermolecular Inc., SanDisk 3D LLC, Kabushiki Kaisha Toshiba
    Inventors: Hieu Pham, Vidyut Gopal, Imran Hashim, Tim Minvielle, Yun Wang, Takeshi Yamaguchi, Hong Sheng Yang
  • Publication number: 20130336037
    Abstract: A vertical switching layer of a 3D memory device serves to switch a set of vertical local bit lines to a corresponding set of global bit lines, the vertical switching layer being a 2D array of TFT channels of vertical thin-film transistors (TFTs) aligned to connect to an array of local bit lines, each TFT switching a local bit line to a corresponding global bit line. The TFTs in the array have a separation of lengths Lx and Ly along the x- and y-axis respectively such that a gate material layer forms a surround gate around each TFT in an x-y plane and has a thickness that merges to form a row select line along the x-axis while maintaining a separation of length Ls between individual row select lines. The surround gate improves the switching capacity of the TFTs.
    Type: Application
    Filed: March 15, 2013
    Publication date: December 19, 2013
    Applicant: SanDisk 3D LLC
    Inventors: Yung-Tin Chen, Steven J. Radigan, Roy E. Scheuerlein, Raul Adrian Cernea
  • Publication number: 20130337642
    Abstract: Methods for forming or patterning nanostructure arrays are provided. The methods involve formation of arrays on coatings comprising nanostructure association groups, formation of arrays in spin-on-dielectrics, solvent annealing after nanostructure deposition, patterning using resist, and/or use of devices that facilitate array formation. Related devices for forming nanostructure arrays are also provided, as are devices including nanostructure arrays (e.g., memory devices).
    Type: Application
    Filed: August 1, 2013
    Publication date: December 19, 2013
    Applicant: SanDisk 3D LLC
    Inventors: Jian Chen, Karen Chu Cruden, Xiangfeng Duan, Chao Liu, J. Wallace Parce
  • Publication number: 20130336038
    Abstract: In a 3D nonvolatile memory with 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 from a bottom plane to a top plane stacked in the z-direction over a semiconductor substrate; a plurality of local bit lines elongated in the z-direction through the plurality of layers and arranged in a two-dimensional rectangular array of bit line pillars having rows in the x-direction and columns in the y-direction; the 3D nonvolatile memory further having a plurality of staircase word lines spaced apart in the y-direction and between and separated from the plurality of bit line pillars at a plurality of crossings, individual staircase word lines each having a series of alternating steps 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.
    Type: Application
    Filed: March 15, 2013
    Publication date: December 19, 2013
    Applicant: SanDisk 3D LLC
    Inventors: Raul Adrian Cernea, George Samachisa
  • Publication number: 20130337646
    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: Application
    Filed: March 15, 2013
    Publication date: December 19, 2013
    Applicant: SanDisk 3D LLC
    Inventors: Raul Adrian Cernea, Henry Chien
  • Publication number: 20130334484
    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.
    Type: Application
    Filed: August 21, 2013
    Publication date: December 19, 2013
    Applicants: Intermolecular Inc., SanDisk 3D LLC, Kabushiki Kaisha Toshiba
    Inventors: Yun Wang, Tony P. Chiang, Vidyut Gopal, Imran Hashim, Dipankar Pramanik
  • Publication number: 20130339571
    Abstract: A 3D memory with vertical local bit lines global bit lines has an in-line vertical switch in the form of a thin film transistor (TFT) formed as a vertical structure, to switch a local bit line to a global bit line. The TFT is implemented to switch a maximum of current carried by the local bit line by a strongly coupled select gate which must be fitted within the space around the local bit line. Maximum thickness of the select gate is implemented with the select gate exclusively occupying the space along the x-direction from both sides of the local bit line. The switches for odd and even bit lines of the row are staggered and offset in the z-direction so that the select gates of even and odd local bit lines are not coincident along the x-direction. The switching is further enhanced with a wrap-around select gate.
    Type: Application
    Filed: March 15, 2013
    Publication date: December 19, 2013
    Applicant: SanDisk 3D LLC
    Inventors: Raul Adrian Cernea, Roy E. Scheuerlein
  • Patent number: 8605486
    Abstract: A memory system includes an X line, a first Y line, a second Y line, a semiconductor region of a first type running along the X line, first switching material and a first semiconductor region of a second type between the first Y line and the semiconductor region of the first type, second switching material and a second semiconductor region of the second type between the second Y line and the semiconductor region of the first type, and control circuitry. The control circuitry changes the programming state of the first switching material to a first state by causing a first current to flow from the second Y line to the first Y line through the first switching material, the second switching material, the semiconductor region of the first type, the first semiconductor region of the second type and the second semiconductor region of the second type.
    Type: Grant
    Filed: August 21, 2012
    Date of Patent: December 10, 2013
    Assignee: Sandisk 3D LLC
    Inventor: Roy E. Scheuerlein
  • Publication number: 20130320287
    Abstract: A method of forming a memory cell is provided that includes forming a steering element above a substrate, forming a material layer on the substrate, patterning and etching the material layer, and oxidizing the patterned and etched material layer to form a reversible resistance-switching material. Numerous other aspects are provided.
    Type: Application
    Filed: August 12, 2013
    Publication date: December 5, 2013
    Applicant: SanDisk 3D LLC
    Inventors: April D. Schricker, S. Brad Herner, Mark H. Clark
  • Patent number: 8598682
    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: Grant
    Filed: November 13, 2012
    Date of Patent: December 3, 2013
    Assignees: Intermolecular, Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLC
    Inventors: Dipankar Pramanik, Tony P. Chiang, Mankoo Lee
  • Publication number: 20130313505
    Abstract: A memory cell is provided that includes a semiconductor pillar and a reversible resistance-switching element coupled to the semiconductor pillar. The semiconductor pillar includes a heavily doped bottom region of a first conductivity type, a heavily doped top region of a second conductivity type, and a lightly doped or intrinsic middle region interposed between and contacting the top and bottom regions. The middle region includes a first proportion of germanium greater than a proportion of germanium in the top region and/or the bottom region. The reversible resistivity-switching element includes a material selected from the group consisting of NiO, Nb2O5, TiO2, HfO2, Al2O3, CoO, MgOx, CrO2, VO, BN, and AlN. Numerous other aspects are provided.
    Type: Application
    Filed: November 16, 2012
    Publication date: November 28, 2013
    Applicant: SanDisk 3D LLC
    Inventor: Scott Brad Herner
  • Publication number: 20130314971
    Abstract: Methods involve using a memory array having memory cells comprising a diode and an antifuse, in which the antifuse is made smaller and programmed at lower voltage by using an antifuse material having a higher dielectric constant and a higher acceleration factor than those of silicon dioxide, and in which the diode is made of a material having a lower band gap than that of silicon. Such memory arrays can be made to have long operating lifetimes by using the high acceleration factor and lower band gap materials. Antifuse materials having dielectric constants between 5 and 27, for example, hafnium silicon oxynitride or hafnium silicon oxide, are particularly effective. Diode materials with band gaps lower than that of silicon, such as germanium or a silicon-germanium alloy, are particularly effective.
    Type: Application
    Filed: November 16, 2012
    Publication date: November 28, 2013
    Applicant: SanDisk 3D LLC
    Inventor: SanDisk 3D LLC
  • Publication number: 20130314970
    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: Application
    Filed: July 29, 2013
    Publication date: November 28, 2013
    Applicant: SanDisk 3D LLC
    Inventors: Mark G. Johnson, Thomas H. Lee, Vivek Subramanian, Paul Michael Farmwald, James M. Cleeves
  • Publication number: 20130313503
    Abstract: A memory is described that includes a shared diode layer and a memory element coupled to the diode layer. The memory element has a pie slice-shape, and includes a sidewall having a carbon film thereon. Numerous other aspects are also disclosed.
    Type: Application
    Filed: November 12, 2012
    Publication date: November 28, 2013
    Applicant: SANDISK 3D LLC
    Inventor: SanDisk 3D LLC