Magnetic Thin Film Patents (Class 365/171)
  • Patent number: 8981503
    Abstract: An STT MTJ cell is formed with a magnetic anisotropy of its free and reference layers that is perpendicular to their planes of formation. The reference layer of the cell is an SAF multilayered structure with a single magnetic domain to enhance the bi-stability of the magnetoresistive states of the cell. The free layer of the cell is etched back laterally from the reference layer, so that the fringing stray field of the reference layer is no more than 15% of the coercivity of the free layer and has minimal effect on the free layer.
    Type: Grant
    Filed: March 16, 2012
    Date of Patent: March 17, 2015
    Assignee: Headway Technologies, Inc.
    Inventors: Robert Beach, Guenole Jan, Yu-Jen Wang, Witold Kula, Po-Kang Wang
  • Patent number: 8976577
    Abstract: One embodiment of a magnetic memory device comprises a substrate and a plurality of planar memory arrays stacked on the substrate, each memory array includes a plurality of parallel first conductive lines, each first conductive line includes a ferromagnetic cladding, a plurality of parallel second conductive lines overlapping the first conductive lines at a plurality of intersection regions, a plurality of magnetic tunnel junctions, each magnetic tunnel junction has a controllable electrical resistance, is disposed at an intersection region and electrically coupled to one of the first conductive lines at its first end and to one of the second conductive lines at its second end. The electrical resistance of the magnetic tunnel junction is controlled by a joint effect of a spin-polarized current running between the first and second ends and a bias magnetic field applied simultaneously to said each magnetic tunnel junction. Other embodiments are described and shown.
    Type: Grant
    Filed: July 20, 2012
    Date of Patent: March 10, 2015
    Inventors: Tom A. Agan, Alexander Mikhailovich Shukh
  • Patent number: 8975091
    Abstract: The present disclosure relates to a magnetic tunnel junction (MTJ) device and its fabricating method. Through forming MTJ through a damascene process, device damage due to the etching process and may be avoided. In some embodiments, a spacer is formed between a first portion and a second portion of the MTJ to prevent the tunnel insulating layer of the MTJ from being damaged in subsequent processes, greatly increasing product yield thereby. In other embodiments, signal quality may be improved and magnetic flux leakage may be reduced through the improved cup-shaped MTJ structure of this invention.
    Type: Grant
    Filed: September 9, 2014
    Date of Patent: March 10, 2015
    Assignee: Semiconductor Manufacturing International (Beijing) Corporation
    Inventors: Min-Hwa Chi, Mieno Fumitake
  • Patent number: 8976578
    Abstract: A memory element has a layered configuration, including a memory layer in which a magnetization direction is changed corresponding to information; the magnetization direction being changed by applying a current in a lamination direction of the layered configuration to record the information in the memory layer, a magnetization-fixed layer in which a magnetization direction is fixed, an intermediate layer that is formed of a non-magnetic material and is provided between the memory layer and the magnetization-fixed layer, and a perpendicular magnetic anisotropy inducing layer, the memory layer including a first ferromagnetic layer, a first bonding layer, a second ferromagnetic layer, a second bonding layer and a third ferromagnetic layer laminated in the stated order.
    Type: Grant
    Filed: November 13, 2012
    Date of Patent: March 10, 2015
    Assignee: Sony Corporation
    Inventors: Yutaka Higo, Masanori Hosomi, Hiroyuki Ohmori, Kazuhiro Bessho, Tetsuya Asayama, Kazutaka Yamane, Hiroyuki Uchida
  • Patent number: 8971103
    Abstract: A technique is provided for a thermally assisted magnetoresistive random access memory device. The device has a synthetic antiferromagnetic layer disposed on an antiferromagnetic layer. The synthetic antiferromagnetic layer has a first ferromagnetic storage layer, a non-magnetic coupling layer disposed on the first ferromagnetic storage layer, and a second ferromagnetic storage layer disposed on the non-magnetic coupling layer. A non-magnetic tunnel barrier is disposed on the second ferromagnetic storage layer, and a ferromagnetic sense layer is disposed on the non-magnetic tunnel barrier. A first ferromagnetic critical temperature of the first ferromagnetic storage layer is higher than an antiferromagnetic critical temperature of the antiferromagnetic layer, is higher than a second ferromagnetic critical temperature of the second ferromagnetic storage layer, and is higher than a third ferromagnetic critical temperature of the ferromagnetic sense layer.
    Type: Grant
    Filed: March 13, 2013
    Date of Patent: March 3, 2015
    Assignee: International Business Machines Corporation
    Inventors: Anthony J. Annunziata, Philip L. Trouilloud, Daniel Worledge
  • Patent number: 8971088
    Abstract: A method for programming a non-volatile memory device includes providing an as-fabricated state-change device having an aluminum doped zinc oxide material first electrode, a p++ polysilicon material second electrode, and a zinc oxide (ZnO) material state-change material there between. A first amplitude bias voltage is applied to the first electrode of the as-fabricated state-change device causing the ZnO material to change form an as-fabricated state to a first state. A second amplitude bias voltage having an opposite polarity having an amplitude similar to the first amplitude is applied to cause the ZnO to change from the first state to a second state substantially similar as the as-fabricated state. A third amplitude bias voltage having a same polarity to the first bias voltage and having an amplitude dissimilar to the first bias voltage is applied to cause the ZnO to change from the second state to a third state.
    Type: Grant
    Filed: March 22, 2012
    Date of Patent: March 3, 2015
    Assignee: Crossbar, Inc.
    Inventors: Sung Hyun Jo, Tanmay Kumar
  • Patent number: 8971100
    Abstract: Methods using a sequence of externally generated magnetic fields to initialize the magnetization directions of each of the layers in perpendicular MTJ MRAM elements for data and reference bits when the required magnetization directions are anti-parallel are described. The coercivity of the fixed pinned and reference layers can be made unequal so that one of them can be switched by a magnetic field that will reliably leave the other one unswitched. Embodiments of the invention utilize the different effective coercivity fields of the pinned, reference and free layers to selectively switch the magnetization directions using a sequence of magnetic fields of decreasing strength. Optionally the chip or wafer can be heated to reduce the required field magnitude. It is possible that the first magnetic field in the sequence can be applied during an annealing step in the MRAM manufacture process.
    Type: Grant
    Filed: July 11, 2012
    Date of Patent: March 3, 2015
    Assignee: Avalanche Technology, Inc.
    Inventors: Yuchen Zhou, Yiming Huai
  • Patent number: 8971107
    Abstract: A magnetic memory system includes a magnetic random access memory (MRAM) including a plurality of magnetic memory banks and operative to store data during a write operation initiated by a write command. The magnetic memory system further includes a first-in-first-out (FIFO) interface device coupled to the MRAM and including a plurality of FIFOs Each of the magnetic memory banks is coupled to a respective one of the plurality of FIFOs, the FIFO being operative to queue write commands on a per magnetic memory bank basis and further operative to issue the queued write commands at a time when the MRAM is not in use, wherein concurrent write operations are performed to at least two of the plurality of magnetic memory banks.
    Type: Grant
    Filed: May 19, 2014
    Date of Patent: March 3, 2015
    Assignee: Avalanche Technology, Inc.
    Inventors: Petro Estakhri, Ebrahim Abedifard, Frederick Jaffin, Siamack Nemazie
  • Patent number: 8971101
    Abstract: A semiconductor device includes a memory cell. The cell includes: a magnetic recording layer (MRL) formed of ferromagnetic material; first and second magnetization fixed layers (MFLs) coupled to the MRL; first and second reference layers (RLs) opposed to the MRL; and first and second tunnel barrier films (TBFs) inserted between the MRL and the first and second reference layers (RLs), respectively. The first MFL has a magnetization fixed in a first direction, and the second MFL has a magnetization fixed in a second direction opposite to the first direction. The first and second RLs and the first and second TBFs are positioned between the first and second MFLs. The first RL has a magnetization fixed in a third direction which is selected from the first and second directions, and the second RL has a magnetization fixed in a fourth direction opposite to the third direction.
    Type: Grant
    Filed: July 26, 2012
    Date of Patent: March 3, 2015
    Assignee: Renesas Electronics Corporation
    Inventor: Masaru Matsui
  • Publication number: 20150055410
    Abstract: Memory circuit and method for at least partially dissipating an external magnetic field before the magnetic field affects operation of an array of addressable magnetic storage element stacks in the memory circuit. Multiple dummy magnetic storage element stacks are provided around the periphery of the array. Each of the dummy stacks is substantially circular for orienting along the external magnetic field, thereby causing the dissipation. Each of the addressable and the dummy stacks may be formed with a magnetic tunnel junction (MTJ).
    Type: Application
    Filed: June 6, 2011
    Publication date: February 26, 2015
    Applicant: MAGSIL CORPORATION
    Inventor: Krishnakumar Mani
  • Patent number: 8964459
    Abstract: According to one embodiment, a magnetoresistive element includes a first magnetic layer, a second magnetic layer, a non-magnetic layer formed between the first magnetic layer and the second magnetic layer, a charge storage layer having a first surface and a second surface different from the first surface, the first surface facing the second magnetic layer, a first insulating layer formed between the second magnetic layer and the first surface of the charge storage layer, and a second insulating layer formed on the second surface of the charge storage layer.
    Type: Grant
    Filed: February 28, 2013
    Date of Patent: February 24, 2015
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tsukasa Nakai, Takashi Izumida, Jyunichi Ozeki, Masaki Kondo, Toshiyuki Enda, Nobutoshi Aoki
  • Patent number: 8963264
    Abstract: Various embodiments may configure a magnetic stack with a magnetically free layer, a reference structure, and a biasing layer. The magnetically free layer and reference structure can each be respectively configured with first and second magnetizations aligned along a first plane while the biasing layer has a third magnetization aligned along a second plane, substantially perpendicular to the first plane.
    Type: Grant
    Filed: June 29, 2012
    Date of Patent: February 24, 2015
    Assignee: Seagate Technology LLC
    Inventors: Dimitar Velikov Dimitrov, Wonjoon Jung
  • Patent number: 8957487
    Abstract: A tunneling magneto-resistor reference unit for sensing a magnetic field includes a first MTJ (magnetic tunneling junction) device and a second MTJ device connected in parallel. The first MTJ device has a first pinned layer having a first pinned magnetization at a pinned direction, and a first free layer having a first free magnetization parallel to the pinned direction in a zero magnetic field. The second MTJ device has a second pinned layer having a second pinned magnetization at the pinned direction, and a second free layer having a second free magnetization anti-parallel to the pinned direction in a zero magnetic field. Major axes of the first and second MTJ devices have an angle of 45 degrees to a direction of an external magnetic field when sensed.
    Type: Grant
    Filed: August 31, 2012
    Date of Patent: February 17, 2015
    Assignee: Industrial Technology Research Institute
    Inventors: Yung-Hung Wang, Sheng-Huang Huang, Kuei-Hung Shen, Keng-Ming Kuo
  • Patent number: 8958241
    Abstract: A magnetic memory according to an embodiment includes: a magnetic nanowire; first insulating layers provided on a first surface of the magnetic nanowire, each of the first insulating layers having a first and second end faces, a thickness of the first insulating layer over the first end face being thicker than a thickness of the first insulating layer over the second end face; first electrodes on surfaces of the first insulating layers opposite to the first surface; second insulating layers on the second surface of the magnetic nanowire, each of the second insulating layers having a third and fourth end faces, a thickness of the second insulating layer over the third surface being thicker than a thickness of the second insulating layer over the fourth end face; and second electrodes on surfaces of the second insulating layers.
    Type: Grant
    Filed: September 9, 2013
    Date of Patent: February 17, 2015
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tsuyoshi Kondo, Hirofumi Morise, Shiho Nakamura, Takuya Shimada, Yoshiaki Fukuzumi, Hideaki Aochi
  • Patent number: 8958239
    Abstract: One embodiment provides a magnetic memory element, including: a first ferromagnetic layer whose magnetization is variable; a second ferromagnetic layer which has a first band split into a valence band and a conduction band and a second band being continuous at least from the valence band to the conduction band; and a nonmagnetic layer provided between the first ferromagnetic layer and the second ferromagnetic layer.
    Type: Grant
    Filed: June 26, 2012
    Date of Patent: February 17, 2015
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomoaki Inokuchi, Takao Marukame, Mizue Ishikawa, Hideyuki Sugiyama, Masahiko Nakayama, Tatsuya Kishi, Hiroaki Yoda, Yoshiaki Saito
  • Patent number: 8953366
    Abstract: The present invention proposes an electronic memory device comprising a memory line including a memory domain. The memory line may contain a number of memory domains and a number of fixed domains, wherein each memory domain stores a single binary bit value. A multiferroic element may be disposed proximate to each memory domain allowing the magnetization of the memory domain to be changed using a spin torque current, and ensuring the stability of the magnetization of the domain when it is not being written. The domain boundary between the memory domain and one of its adjacent fixed domains may thereby be moved. An antiferromagnetic element may be disposed proximate to each fixed domain to ensure the stability of the magnetization of these. The value of each memory domain may be read by applying a voltage to a magnetic tunnel junction comprising the memory domain and measuring the current flowing through it.
    Type: Grant
    Filed: May 11, 2011
    Date of Patent: February 10, 2015
    Assignee: University of Virginia Patent Foundation
    Inventors: Stuart A. Wolf, Jiwei Lu, Mircea R. Stan
  • Patent number: 8953369
    Abstract: According to one embodiment, a magnetoresistive element includes first and second magnetic layers and a first nonmagnetic layer. The first magnetic layer has an axis of easy magnetization perpendicular to a film plane, and a variable magnetization. The second magnetic layer has an axis of easy magnetization perpendicular to a film plane, and an invariable magnetization. The first nonmagnetic layer is provided between the first and second magnetic layers. The second magnetic layer includes third and fourth magnetic layers, and a second nonmagnetic layer formed between the third and fourth magnetic layers. The third magnetic layer is in contact with the first nonmagnetic layer and includes Co and at least one of Zr, Nb, Mo, Hf, Ta, and W.
    Type: Grant
    Filed: January 20, 2014
    Date of Patent: February 10, 2015
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Toshihiko Nagase, Eiji Kitagawa, Katsuya Nishiyama, Tadashi Kai, Koji Ueda, Daisuke Watanabe
  • Patent number: 8947915
    Abstract: A thermal spin torque transfer magnetoresistive random access memory (MRAM) apparatus includes a magnetic tunnel junction and a tunnel junction programming circuit. The magnetic tunnel junction includes a reference layer having a fixed magnetic polarity, a tunnel barrier layer, and a free layer on an opposite side of the tunnel barrier layer from the reference layer. The free layer includes a first layer having a first Curie temperature and a second layer having a second Curie temperature different from the first Curie temperature. The tunnel junction programming circuit is configured to apply a current through the magnetic tunnel junction to generate a write temperature in the magnetic tunnel junction and to write to the free layer of the magnetic tunnel junction.
    Type: Grant
    Filed: December 17, 2012
    Date of Patent: February 3, 2015
    Assignee: International Business Machines Corporation
    Inventors: Daniel C. Worledge, Guohan Hu
  • Patent number: 8947905
    Abstract: A method of driving a nonvolatile memory device including applying a reset voltage to a unit memory cell, reading a reset current of the unit memory cell, confirming whether the reset current is within a first current range, if the reset current is not within the first current range, changing the reset voltage and applying a changed reset voltage or applying again the reset voltage to the unit memory cell after applying a set voltage to the unit memory cell, if the reset current is within the first current range, confirming whether a difference between the present reset current and an immediately previous set current is within a second current range, and, if the difference is not within the second current range, applying the reset voltage or applying again the reset voltage to the unit memory cell after applying a set voltage to the unit memory cell.
    Type: Grant
    Filed: June 14, 2012
    Date of Patent: February 3, 2015
    Assignee: Samsung Electronics Co., Ltd
    Inventors: Man Chang, Young-bae Kim, Dong-soo Lee, Chang-bum Lee, Seung-ryul Lee, Chang-jung Kim, Myoung-jae Lee, Kyung-min Kim
  • Patent number: 8947914
    Abstract: Provided is a magnetic tunneling junction device including a fixed magnetic structure; a free magnetic structure; and a tunnel barrier between the fixed magnetic structure and the free magnetic structure, at least one of the fixed magnetic structure and the free magnetic structure including a perpendicular magnetization preserving layer, a magnetic layer between the perpendicular magnetization preserving layer and the tunnel barrier, and a perpendicular magnetization inducing layer between the perpendicular magnetization preserving layer and the magnetic layer.
    Type: Grant
    Filed: February 16, 2012
    Date of Patent: February 3, 2015
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Jeong Heon Park, Woo Chang Lim, Sechung Oh, Woojin Kim, Sang Hwan Park, Jang Eun Lee
  • Patent number: 8946834
    Abstract: A CoFeB or CoFeNiB magnetic layer wherein the boron content is 25 to 40 atomic % and with a thickness <20 Angstroms is used to achieve high perpendicular magnetic anisotropy and enhanced thermal stability in magnetic devices. A dusting layer made of Co, Ni, Fe or alloy thereof is added to top and bottom surfaces of the CoFeB layer to increase magnetoresistance as well as improve Hc and Hk. Another embodiment includes a non-magnetic metal insertion in the CoFeB free layer. The CoFeB layer with elevated B content may be incorporated as a free layer, dipole layer, or reference layer in STT-MRAM memory elements or in spintronic devices including a spin transfer oscillator. Thermal stability is increased such that substantial Hk is retained after annealing to at least 400° C. for 1 hour. Ku enhancement is achieved and the retention time of a memory cell for STT-MRAM designs is increased.
    Type: Grant
    Filed: March 1, 2012
    Date of Patent: February 3, 2015
    Assignee: Headway Technologies, Inc.
    Inventors: Yu-Jen Wang, Witold Kula, Guenole Jan
  • Patent number: 8947919
    Abstract: One embodiment of the present invention includes a diode-addressable current-induced magnetization switching (CIMS) memory element including a magnetic tunnel junction (MTJ) and a diode formed on top of the MTJ for addressing the MTJ.
    Type: Grant
    Filed: September 3, 2013
    Date of Patent: February 3, 2015
    Assignee: Avalanche Technology, Inc.
    Inventors: Rajiv Yadav Ranjan, Parviz Keshtbod
  • Patent number: 8947907
    Abstract: An integrated circuit device can include a plurality of memory cells, each including at least one element programmable between different impedance states by application of a voltage or current; a plurality of bit line groups, each bit line group including multiple bit lines, each bit line being coupled to multiple memory cells; a plurality of current source circuits coupled to the bit line groups, each current source circuit configured to couple the bit lines of its respective group to at least a first bias node or a second bias node.
    Type: Grant
    Filed: April 13, 2013
    Date of Patent: February 3, 2015
    Assignee: Adesto Technologies Corporation
    Inventors: Shane Charles Hollmer, John Dinh
  • Patent number: 8947917
    Abstract: A thermal spin torque transfer magnetoresistive random access memory (MRAM) apparatus includes a magnetic tunnel junction and a tunnel junction programming circuit. The magnetic tunnel junction includes a reference layer having a fixed magnetic polarity, a tunnel barrier layer, and a free layer on an opposite side of the tunnel barrier layer from the reference layer. The free layer includes a first layer having a first Curie temperature and a second layer having a second Curie temperature different from the first Curie temperature. The tunnel junction programming circuit is configured to apply a current through the magnetic tunnel junction to generate a write temperature in the magnetic tunnel junction and to write to the free layer of the magnetic tunnel junction.
    Type: Grant
    Filed: August 16, 2013
    Date of Patent: February 3, 2015
    Assignee: International Business Machines Corporation
    Inventors: Daniel C. Worledge, Guohan Hu
  • Patent number: 8947908
    Abstract: A non-volatile memory device structure includes first electrodes comprising conductive silicon-containing material, a plurality of resistive switching material stacks comprising first resistive switching material and second resistive switching material overlying the first electrode, wherein the first resistive switching material comprises a first resistance switching voltage and the second resistive switching material comprises a second resistance switching voltage less than the first amplitude, second electrodes comprising metal material overlying and electrically coupled to the plurality of resistive switching material stacks, wherein a plurality of memory elements are formed from the first plurality of electrodes, the plurality of resistive switching material stacks, and the second plurality of electrodes.
    Type: Grant
    Filed: June 17, 2013
    Date of Patent: February 3, 2015
    Assignee: Crossbar, Inc.
    Inventor: Sung Hyun Jo
  • Patent number: 8947921
    Abstract: The present disclosure concerns a multilevel magnetic element comprising a first tunnel barrier layer between a soft ferromagnetic layer having a magnetization that can be freely aligned and a first hard ferromagnetic layer having a magnetization that is fixed at a first high temperature threshold and freely alignable at a first low temperature threshold. The magnetic element further comprises a second tunnel barrier layer and a second hard ferromagnetic layer having a magnetization that is fixed at a second high temperature threshold and freely alignable at a first low temperature threshold; the soft ferromagnetic layer being comprised between the first and second tunnel barrier layers. The magnetic element disclosed herein allows for writing four distinct levels using only a single current line.
    Type: Grant
    Filed: January 14, 2014
    Date of Patent: February 3, 2015
    Assignee: Crocus Technology SA
    Inventor: Bertrand Cambou
  • Patent number: 8941196
    Abstract: Orthogonal spin-torque bit cells whose spin torques from a perpendicular polarizer and an in-plane magnetized reference layer are constructively or destructively combined. An orthogonal spin-torque bit cell includes a perpendicular magnetized polarizing layer configured to provide a first spin-torque; an in-plane magnetized free layer and a reference layer configured to provide a second spin-torque. The first spin-torque and the second spin-torque combine and the combined first spin-torque and second spin-torque influences the magnetic state of the in-plane magnetized free layer. The in-plane magnetized free layer and the reference layer form a magnetic tunnel junction. The first spin-torque and second spin-torque can combine constructively to lower a switching current, increase a switching speed, and/or torque decrease an operating energy of the orthogonal spin-torque bit cell.
    Type: Grant
    Filed: July 3, 2013
    Date of Patent: January 27, 2015
    Assignee: New York University
    Inventors: Daniel Bedau, Huanlong Liu, Andrew David Kent
  • Patent number: 8934294
    Abstract: A semiconductor integrated circuit device, a method of manufacturing the same, and a method of driving the same are provided. The device includes a semiconductor substrate, an upper electrode extending from a surface of the semiconductor substrate; a plurality of switching structures extending from both sidewalls of the upper electrode in a direction parallel to the surface of the semiconductor substrate, and a phase-change material layer disposed between the plurality of switching structures and the upper electrode.
    Type: Grant
    Filed: February 18, 2014
    Date of Patent: January 13, 2015
    Assignee: SK Hynix Inc.
    Inventors: Myoung Sub Kim, Soo Gil Kim, Nam Kyun Park, Sung Cheoul Kim, Gap Sok Do, Joon Seop Sim, Hyun Jeong Lee
  • Patent number: 8934288
    Abstract: Magnetic memory devices are provided, the devices include at least memory cell and a reference cell on a substrate. The memory cells include a first base magnetic layer, a free layer, and a first tunnel barrier layer between the first base magnetic layer and free layer. The reference memory cell includes a second base magnetic layer, a reference magnetic layer, and a second tunnel barrier layer between the second base magnetic layer and reference magnetic layer. The reference magnetic layer has a magnetic direction substantially perpendicular to that of the free layer.
    Type: Grant
    Filed: February 24, 2012
    Date of Patent: January 13, 2015
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Sechung Oh, Hyungrok Oh
  • Patent number: 8934290
    Abstract: A magnetoresistance effect device including a multilayer structure having a pair of ferromagnetic layers and a barrier layer positioned between them, wherein at least one ferromagnetic layer has at least the part contacting the barrier layer made amorphous and the barrier layer is an MgO layer having a highly oriented texture structure.
    Type: Grant
    Filed: September 20, 2013
    Date of Patent: January 13, 2015
    Assignees: Canon Anelva Corporation, National Institute of Advanced Industrial Science Nad Technology
    Inventors: David D. Djayaprawira, Koji Tsunekawa, Motonobu Nagai, Hiroki Maehara, Shinji Yamagata, Naoki Watanabe, Shinji Yuasa
  • Patent number: 8934295
    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: October 4, 2014
    Date of Patent: January 13, 2015
    Assignee: Sandisk 3D LLC
    Inventors: Yingchang Chen, Pankaj Kalra, Chandrasekhar Gorla
  • Patent number: 8929132
    Abstract: A write driver for writing to a spin-torque magnetoresistive random access memory (ST-MRAM) minimizes sub-threshold leakage of the unselected (off) word line select transistors in the selected column. An effective metal resistance in the bit line and/or source line is reduced and power supply noise immunity is increased. Write driver bias signals are isolated from global bias signals, and a first voltage is applied at one end of a bit line using one of a first NMOS-follower circuit or a first PMOS-follower circuit. A second voltage is applied at opposite ends of a source line using, respectively, second and third PMOS-follower circuits, or second and third NMOS-follower circuits.
    Type: Grant
    Filed: November 16, 2012
    Date of Patent: January 6, 2015
    Assignee: Everspin Technologies, Inc.
    Inventors: Syed M. Alam, Thomas Andre
  • Patent number: 8929127
    Abstract: A write and/or read current generator for nonvolatile memory device, especially for Spin Transfer Torque Magnetoresistive Random Access Memory (STT-MRAM), may include a current supplying circuit which changes a level of a sample current, determines a resistance state change current of a sample bit cell based on a feedback signal obtained through the sample bit cell whose resistance state is changed according to a level of the sample current. The current supplying circuit may calibrate a write and/or read current of a memory cell in response to a sample current applied at a point of time when a resistance state of the sample bit cell is switched into another resistance state. A calibration circuit may generate the feedback signal indicating a resistance area of a predetermined resistance range to which a resistance state of the sample bit cell belongs.
    Type: Grant
    Filed: April 1, 2014
    Date of Patent: January 6, 2015
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Artur Antonyan
  • Patent number: 8929122
    Abstract: Junction diodes fabricated in standard CMOS logic technologies can be used as program selectors for a programmable resistive device, such as electrical fuse, contact/via fuse, anti-fuse, or emerging nonvolatile memory such as MRAM, PCM, CBRAM, or RRAM. The diode can be constructed by P+ and N+ active regions on an N well as the P and N terminals of the diode. By applying a high voltage to the P terminal of a diode and switching the N terminal of a diode to a low voltage for proper duration of time, a current flows through a resistive element in series with the program selector may change the resistance state. The P+ active region of the diode can be isolated from the N+ active region in the N well by using dummy MOS gate, SBL, or STI isolations. If the resistive element is an interconnect fuse based on CMOS gate material, the resistive element can be coupled to the P+ active region by an abutted contact such that the element, active region, and metal can be connected in a single rectangular contact.
    Type: Grant
    Filed: February 14, 2011
    Date of Patent: January 6, 2015
    Inventor: Shine C. Chung
  • Patent number: 8923044
    Abstract: Systems and methods for multiple-time programmable (MTP) devices. An MTP device includes a magnetic tunnel junction (MTJ) device programmable to a plurality of states based on voltage applied across the MTJ device. The plurality of states include a first resistance state corresponding to a first binary value stored in the MTJ device based on a first voltage, a second resistance state corresponding to a second binary value stored in the MTJ device based on a second voltage, a third resistance state corresponding to a breakdown of a barrier layer of the MTJ device based on a third voltage, and a fourth resistance state corresponding to an open fuse based on a fourth voltage.
    Type: Grant
    Filed: August 20, 2012
    Date of Patent: December 30, 2014
    Assignee: QUALCOMM Incorporated
    Inventors: Xia Li, Kangho Lee, Jung Pill Kim, Taehyun Kim, Wah Nam Hsu, Seung H. Kang, Xiaochun Zhu, Wei-Chuan Chen, Sungryul Kim
  • Patent number: 8923038
    Abstract: Methods of forming magnetic memory cells are disclosed. Magnetic and non-magnetic materials are formed into a primal precursor structure in an initial stress state of essentially no strain, compressive strain, or tensile strain. A stress-compensating material, e.g., a non-sacrificial, conductive material, is formed to be disposed on the primal precursor structure to form a stress-compensated precursor structure in a net beneficial stress state. Thereafter, the stress-compensated precursor structure may be patterned to form a cell core of a memory cell. The net beneficial stress state of the stress-compensated precursor structure lends to formation of one or more magnetic regions, in the cell core, exhibiting a vertical magnetic orientation without deteriorating a magnetic strength of the one or more magnetic regions. Also disclosed are memory cells, memory cell structures, semiconductor device structures, and spin torque transfer magnetic random access memory (STT-MRAM) systems.
    Type: Grant
    Filed: June 19, 2012
    Date of Patent: December 30, 2014
    Assignee: Micron Technology, Inc.
    Inventors: Witold Kula, Gurtej S. Sandhu, Stephen J. Kramer
  • Patent number: 8923037
    Abstract: A memory element including a memory layer to hold the information by the magnetization state of a magnetic substance, a magnetization pinned layer having magnetization serving as a reference of the information stored in the memory layer, an intermediate layer formed from a nonmagnetic substance disposed between the memory layer and the magnetization pinned layer, a magnetic coupling layer disposed adjoining the magnetization pinned layer and opposing to the intermediate layer, and a high coercive force layer disposed adjoining the magnetic coupling layer, wherein the information is stored by reversing magnetization of the memory layer, making use of spin torque magnetization reversal generated along with a current passing in the lamination direction of the layered structure including the memory layer, the intermediate layer, and the magnetization pinned layer, and the magnetic coupling layer has a two-layer laminate structure.
    Type: Grant
    Filed: May 7, 2012
    Date of Patent: December 30, 2014
    Assignee: Sony Corporation
    Inventors: Hiroyuki Ohmori, Masanori Hosomi, Kazuhiro Bessho, Yutaka Higo, Kazutaka Yamane, Hiroyuki Uchida, Tetsuya Asayama
  • Patent number: 8923040
    Abstract: A memory has magnetic tunnel junction elements with different resistances in different logic states, for bit positions in memory words accessed by a word line signal coupling each bit cell in the addressed word between a bit line and source line for that bit position. The bit lines and source lines are longer and shorter at different word line locations, causing a resistance body effect. A clamping transistor couples the bit line to a sensing circuit when reading, applying a current through the bit cell and producing a read voltage compared by the sensing circuit to a reference such as a comparable voltage from a reference bit cell circuit having a similar structure. A drive control varies an input to the switching transistor as a function of the word line location, e.g., by word line address, to offset the different bit and source line resistances.
    Type: Grant
    Filed: January 30, 2013
    Date of Patent: December 30, 2014
    Assignee: Taiwan Semiconductor Manufacturing Co., Ltd.
    Inventors: Kai-Chun Lin, Hung-Chang Yu, Ku-Feng Lin, Yue-Der Chih
  • Patent number: 8923042
    Abstract: A magnetic random access memory according to the present invention is provided with: a magnetic recording layer including a magnetization free region having a reversible magnetization, wherein a write current is flown through the magnetic recording layer in an in-plane direction; a magnetization fixed layer having a fixed magnetization; a non-magnetic layer provided between the magnetization free region and the magnetization fixed layer; and a heat sink structure provided to be opposed to the magnetic recording layer and having a function of receiving and radiating heat generated in the magnetic recording layer. The magnetic random access memory thus-structured radiates heat generated in the magnetic recording layer by using the heat sink structure, suppressing the temperature increase caused by the write current flown in the in-plane direction.
    Type: Grant
    Filed: August 27, 2013
    Date of Patent: December 30, 2014
    Assignee: NEC Corporation
    Inventors: Nobuyuki Ishiwata, Hideaki Numata, Norikazu Ohshima
  • Patent number: 8917542
    Abstract: Spin torque transfer magnetic random access memory devices configured to be programmed unidirectionally and methods of programming such devices. The devices include memory cells having two pinned layers and a free layer therebetween. By utilizing two pinned layers, the spin torque effect on the free layer from each of the two pinned layers, respectively, allows the memory cells to be programmed with unidirectional currents.
    Type: Grant
    Filed: January 21, 2013
    Date of Patent: December 23, 2014
    Assignee: Micron Technology, Inc.
    Inventors: Jun Liu, Gurtej Sandhu
  • Patent number: 8917543
    Abstract: A multi-state spin-torque transfer magnetic random access memory (STTMRAM) is formed on a film and includes a first magnetic tunneling junctions (MTJ) having a first fixed layer, a first sub-magnetic tunnel junction (sub-MTJ) layer and a first free layer. The first fixed layer and first free layer each have a first magnetic anisotropy. The STTMRAM further includes a non-magnetic spacing layer formed on top of the first MTJ layer and a second MTJ formed on top of the non-magnetic spacing layer. The second MTJ has a second fixed layer, a second sub-MTJ layer and a second free layer. The second fixed and second free layers each have a second magnetic anisotropy, wherein at least one of the first or second magnetic anisotropy is perpendicular to the plane of the film.
    Type: Grant
    Filed: May 13, 2013
    Date of Patent: December 23, 2014
    Assignee: Avalanche Technology, Inc.
    Inventors: Rajiv Yadav Ranjan, Parviz Keshtbod
  • Patent number: 8917545
    Abstract: A semiconductor integrated circuit device, a method of manufacturing the same, and a method of driving the same are provided. The device includes a semiconductor substrate, an upper electrode extending from a surface of the semiconductor substrate; a plurality of switching structures extending from both sidewalls of the upper electrode in a direction parallel to the surface of the semiconductor substrate, and a phase-change material layer disposed between the plurality of switching structures and the upper electrode.
    Type: Grant
    Filed: February 18, 2014
    Date of Patent: December 23, 2014
    Assignee: SK Hynix Inc.
    Inventors: Myoung Sub Kim, Soo Gil Kim, Nam Kyun Park, Sung Cheoul Kim, Gap Sok Do, Joon Seop Sim, Hyun Jeong Lee
  • Patent number: 8917546
    Abstract: A method of writing to a magnetic tunnel junction (MTJ) of a magnetic memory array includes an access transistor coupled to the MTJ for reading of and writing to the MTJ, where when the MTJ is written to, at times, by switching its magnetic orientation from an anti-parallel to a parallel magnetic orientation, a bit line that is coupled to one end of the MTJ is raised to Vcc and a voltage that is the sum of Vcc and Vx is applied to the gate of the access transistor, with Vx being approximately the voltage at an opposite end of the MTJ. Further, the voltage of a Source Line (SL), which is coupled to the MTJ using a first transistor of a write driver that is also coupled to the SL, is regulated such that SL remains sufficiently above 0 volts to avoid violation of Vgs exceeding Vcc where Vgs is the gate to source voltage of the access transistor.
    Type: Grant
    Filed: September 24, 2012
    Date of Patent: December 23, 2014
    Assignee: Avalanche Technology, Inc.
    Inventor: Ebrahim Abedifard
  • Patent number: 8913422
    Abstract: Switching current in Spin-Transfer Torque Memory (STTM) can be decreased. A magnetic memory cell is driven with a first pulse on a write line of the memory cell to heat the cell. The cell is then driven with a second pulse on the write line to set the state of the cell.
    Type: Grant
    Filed: September 28, 2012
    Date of Patent: December 16, 2014
    Assignee: Intel Corporation
    Inventors: Elijah V. Karpov, Brian S. Doyle, Kaan Oguz, Satyarth Suri, Robert S. Chau, Charles C. Kuo, Mark L. Doczy, David L. Kencke
  • Patent number: 8911888
    Abstract: Magnetic memories and methods are disclosed. A magnetic memory as described herein includes a plurality of stacked data storage layers to form a three-dimensional magnetic memory. The data storage layers are each formed from a multi-layer structure. At ambient temperatures, the multi-layer structures exhibit an antiparallel coupling state with a near zero net magnetic moment. At higher transition temperatures, the multi-layer structures transition from the antiparallel coupling state to a parallel coupling state with a net magnetic moment. At yet higher temperatures, the multi-layer structure transitions from the antiparallel coupling state to a receiving state where the coercivity of the multi-layer structures drops below a particular level so that magnetic fields from write elements or neighboring data storage layers may imprint data into the data storage layer.
    Type: Grant
    Filed: December 16, 2007
    Date of Patent: December 16, 2014
    Assignee: HGST Netherlands B.V.
    Inventors: Olav Hellwig, Bruce D. Terris, Jan-Ulrich Thiele
  • Patent number: 8913424
    Abstract: Magnetic memory cell comprising two conductors and a magnetic storage element between the two conductors, wherein a magnetic enhancement layer (MEL) is provided in the proximity of at least along a partial length of at least one of the two conductors. The MEL is for enhancing a magnetic field in the element when the two conductors are energized. Methods for operation and fabrication process for the memory cell are also disclosed. The memory cell is particularly for use in magnetic random access memory (MRAM) circuits, when using magnetic tunnel junction (MTJ) stacks as the magnetic storage elements.
    Type: Grant
    Filed: September 17, 2013
    Date of Patent: December 16, 2014
    Assignee: III Holdings 1, LLC
    Inventor: Krishnakumar Mani
  • Patent number: 8913416
    Abstract: Disclosed herein is a variable-resistance memory device including a first common line; a second common line; a storage element connected between the first common line and the second common line to serve as a storage element whose resistance changes in accordance with a voltage applied to the storage element; and a driving control circuit.
    Type: Grant
    Filed: April 30, 2012
    Date of Patent: December 16, 2014
    Assignee: Sony Corporation
    Inventors: Makoto Kitagawa, Tsunenori Shiimoto
  • Patent number: 8912013
    Abstract: A magnetic tunneling junction (MTJ) device and fabrication method is disclosed. In a particular embodiment, an apparatus is disclosed that includes an MTJ device. The MTJ device includes a free layer and a spin torque enhancing layer. The spin torque enhancing layer includes a nano-oxide layer.
    Type: Grant
    Filed: December 19, 2012
    Date of Patent: December 16, 2014
    Assignee: QUALCOMM Incorporated
    Inventors: Xiaochun Zhu, Seung H. Kang, Xia Li
  • Patent number: 8908428
    Abstract: An embodiment includes a three terminal magnetic element for a semiconductor memory device. The magnetic element includes a reference layer; a free layer; a barrier layer disposed between the reference layer and the free layer; a first electrode; an insulating layer disposed between the electrode and the free layer; and a second electrode coupled to sidewalls of the free layer.
    Type: Grant
    Filed: January 29, 2013
    Date of Patent: December 9, 2014
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Adrian E. Ong, Vladimir Nikitin, Mohamad Towfik Krounbi
  • Patent number: 8906695
    Abstract: In general, the present disclosure is directed toward a novel hybrid spintronic device for converting chemical absorption into a change in magnetoresistance. This device uses a novel magnetic material which depends on the attachment of an organic structure to a metallic film for its magnetism. Changes in the chemical environment lead to absorption on the surface of this organometallic bilayer and thus modify its magnetic properties. The change in magnetic properties, in turn, leads to a change in the resistance of a magnetoresistive structure or a spin transistor structure, allowing a standard electrical detection of the chemical change in the sensor surface.
    Type: Grant
    Filed: January 2, 2013
    Date of Patent: December 9, 2014
    Assignee: University of South Carolina
    Inventors: Thomas M. Crawford, Samir Y. Garzon