Magnetic Thin Film Patents (Class 365/171)
  • Patent number: 8488357
    Abstract: Systems and methods for realizing reference currents to improve reliability of sensing operations of segmented semiconductor memory arrays have been achieved. Preferred embodiments of the invention comprise MRAM arrays but the invention could be applied to any other memories requiring access on small, segmented arrays. All embodiments of the invention comprise a folded bit lines scheme, either in adjacent bit lines or in segment-to-segment folded bit lines. In two embodiments alternate strapping of Poly-Si Word Lines in every second segment is achieved by metal layer of Read Word Line and Write Select Line. An embodiment has stored 1 and 0 cells on both sides of a selected segment to be read.
    Type: Grant
    Filed: October 22, 2010
    Date of Patent: July 16, 2013
    Assignee: MagIC Technologies, Inc.
    Inventors: Toshio Sunaga, Lejan Pu, Perng-Fei Yuh, Chao-Hung Chang
  • Patent number: 8482971
    Abstract: A memory array includes a cross-point array of bit and source lines. A memory is disposed at cross-points of the cross-point array. The memory unit includes a magnetic tunnel junction data cell electrically coupled to a bit line and a source line. The magnetic tunnel junction data cell is configured to switch between a high resistance state and a low resistance state by passing a polarized write current through the magnetic tunnel junction data cell. A transistor is electrically between the magnetic tunnel junction data cell and the bit line or source line and a diode is in thermal or electrical contact with the magnetic tunnel junction data cell to assist in resistance state switching.
    Type: Grant
    Filed: May 16, 2012
    Date of Patent: July 9, 2013
    Assignee: Seagate Technology LLC
    Inventors: Xuguang Wang, Yiran Chen, Dimitar V. Dimitrov, Hongyue Liu, Xiaobin Wang
  • Patent number: 8482957
    Abstract: A memory unit including a first transistor spanning a first transistor region in a first layer of the memory unit; a second transistor spanning a second transistor region in a second layer of the memory unit; a first resistive sense memory (RSM) cell spanning a first memory region in a third layer of the memory unit; and a second RSM cell spanning a second memory region in the third layer of the memory unit, wherein the first transistor is electrically coupled to the first RSM cell, and the second transistor is electrically coupled to the second RSM cell, wherein the second layer is between the first and third layers, wherein the first and second transistor have an transistor overlap region, and wherein the first memory region and the second memory region do not extend beyond the first transistor region and the second transistor region.
    Type: Grant
    Filed: October 25, 2011
    Date of Patent: July 9, 2013
    Assignee: Seagate Technology LLC
    Inventors: Xuguang Wang, Yong Lu, Hai Li, Hongyue Liu
  • Patent number: 8482967
    Abstract: An apparatus and method for enhancing data writing and retention to a magnetic memory element, such as in a non-volatile data storage array. In accordance with various embodiments, a programmable memory element has a reference layer and a storage layer. The reference layer is provided with a fixed magnetic orientation. The storage layer is programmed to have a first region with a magnetic orientation antiparallel to said fixed magnetic orientation, and a second region with a magnetic orientation parallel to said fixed magnetic orientation. A thermal assist layer may be incorporated into the memory element to enhance localized heating of the storage layer to aid in the transition of the first region from parallel to antiparallel magnetic orientation during a write operation.
    Type: Grant
    Filed: November 3, 2010
    Date of Patent: July 9, 2013
    Assignee: Seagate Technology LLC
    Inventors: Haiwen Xi, Yuankai Zheng, Xiaobin Wang, Dimitar V. Dimitrov, Pat J. Ryan
  • Patent number: 8482968
    Abstract: An example embodiment is an apparatus for controlling a magnetic direction of a magnetic free layer. The apparatus includes a writer with a first magnetic write layer and a second magnetic write layer. Applying a write voltage across first and second magnetic write layers causes a magnetic anisotropy of one of the magnetic write layers to switch from parallel to the plane of the magnetic write layers to orthogonal to the plane of the magnetic write layers. The magnetic write layer with the magnetic anisotropy parallel to the plane of the magnetic write layers induces the magnetic direction in the magnetic free layer.
    Type: Grant
    Filed: November 13, 2010
    Date of Patent: July 9, 2013
    Assignee: International Business Machines Corporation
    Inventor: Daniel C. Worledge
  • Patent number: 8477531
    Abstract: A semiconductor memory device includes a magnetic tunneling junction (MTJ); and a magnetic feature aligned with the MTJ and approximate the MTJ. When viewed in a direction perpendicular to the MTJ and the magnetic feature, the magnetic feature has a disk shape, and the MTJ has an elliptical shape and is positioned within the disk shape.
    Type: Grant
    Filed: December 15, 2010
    Date of Patent: July 2, 2013
    Assignee: Taiwan Semiconductor Manufacturing Company, Ltd.
    Inventors: Chwen Yu, Tien-Wei Chiang
  • Patent number: 8477530
    Abstract: A non-uniform switching based non-volatile magnetic memory element includes a fixed layer, a barrier layer formed on top of the fixed layer, a first free layer formed on top of the barrier layer, a non-uniform switching layer (NSL) formed on top of the first free layer, and a second free layer formed on top of the non-uniform switching layer. Switching current is applied, in a direction that is substantially perpendicular to the fixed layer, barrier layer, first free layer, non-uniform switching layer and the second free layer causing switching between states of the first free layer, second free layer and non-uniform switching layer with substantially reduced switching current.
    Type: Grant
    Filed: November 28, 2011
    Date of Patent: July 2, 2013
    Assignee: Avalanche Technology, Inc.
    Inventors: Rajiv Yadav Ranjan, Petro Estakhri, Mahmud Assar, Parviz Keshtbod
  • Patent number: 8477529
    Abstract: A magnetic random access memory (MRAM) cell includes an embedded MRAM and an access transistor. The embedded MRAM is formed on a number of metal-interposed-in-interlayer dielectric (ILD) layers, which each include metal dispersed therethrough and are formed on top of the access transistor. An magneto tunnel junction (MTJ) is formed on top of a metal formed in the ILD layers that is in close proximity to a bit line. An MTJ mask is used to pattern the MTJ and is etched to expose the MTJ. Ultimately, metal is formed on top of the bit line and extended to contact the MTJ.
    Type: Grant
    Filed: September 19, 2012
    Date of Patent: July 2, 2013
    Assignee: Avalanche Technology, Inc.
    Inventors: Parviz Keshtbod, Ebrahim Abedifard
  • Patent number: 8477528
    Abstract: A magnetic memory cell 1 is provided with a magnetic recording layer 10 which is a ferromagnetic layer and a pinned layer 30 connected with the magnetic recording layer 10 through a non-magnetic layer 20. The magnetic recording layer 10 has a magnetization inversion region 13, a first magnetization fixed region 11 and a second magnetization fixed region 12. The magnetization inversion region 13 has a magnetization whose orientation is invertible and overlaps the pinned layer 30. The first magnetization fixed region 11 is connected with a first boundary B1 in the magnetization inversion region 13 and a magnetization orientation is fixed on a first direction. The second magnetization fixed region 12 is connected with a second boundary B2 in magnetization inversion region 13 and a magnetization orientation is fixed on a second direction. The first direction and the second direction are opposite to each other.
    Type: Grant
    Filed: September 25, 2007
    Date of Patent: July 2, 2013
    Assignee: NEC Corporation
    Inventors: Takeshi Honda, Noboru Sakimura, Tadahiko Sugibayashi, Hideaki Numata, Norikazu Ohshima
  • Patent number: 8472240
    Abstract: Spin Torque Transfer (STT) memory cell structures and methods are described herein. One or more STT memory cell structures comprise an annular STT stack including a nonmagnetic material between a first ferromagnetic material and a second ferromagnetic material and a soft magnetic material surrounding at least a portion of the annular STT stack.
    Type: Grant
    Filed: May 16, 2011
    Date of Patent: June 25, 2013
    Assignee: Micron Technology, Inc.
    Inventors: Jun Liu, Gurtej S. Sandhu
  • Patent number: 8472242
    Abstract: A magnetoresistive effect memory of an aspect of the present invention including a magnetoresistive effect element including a first magnetic layer having an invariable magnetization direction, a second magnetic layer having a variable magnetization direction, and an interlayer provided between the first magnetic layer and the second magnetic layer, and a reading circuit which passes a pulse-shaped read current through the magnetoresistive effect element to read data stored in the magnetoresistive effect element, wherein the pulse width of the read current is shorter than a period from an initial state to a cooperative coherent precession movement of magnetizations included in the second magnetic layer.
    Type: Grant
    Filed: March 29, 2010
    Date of Patent: June 25, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Naoharu Shimomura, Eiji Kitagawa, Sumio Ikegawa, Yoshihisa Iwata
  • Patent number: 8470462
    Abstract: A STT-RAM MTJ is disclosed with a MgO tunnel barrier formed by natural oxidation process. A Co10Fe70B20/NCC/Co10Fe70B20, Co10Fe70B20/NCC/Co10Fe70B20/NCC, or Co10Fe70B20/NCC/Co10Fe70B20/NCC/Co10Fe70B20 free layer configuration where NCC is a nanocurrent channel layer made of Fe(20%)-SiO2 is used to minimize Jc0 while enabling higher thermal stability, write voltage, read voltage, Ho, and Hc values that satisfy 64 Mb design requirements. The NCC layer is about 10 Angstroms thick to match the minimum Fe(Si) grain diameter size. The MTJ is annealed with a temperature of about 330° C. to maintain a high magnetoresistive ratio while maximizing Hk?(interfacial) for the free layer thereby reducing Heff and lowering the switching current. The Co10Fe70B20 layers are sputter deposited with a low pressure process with a power of about 15 Watts and an Ar flow rate of 40 standard cubic centimeters per minute to lower Heff for the free layer.
    Type: Grant
    Filed: November 30, 2010
    Date of Patent: June 25, 2013
    Assignee: MagIC Technologies, Inc.
    Inventors: Cheng T. Horng, Ru-Ying Tong, Guenole Jan
  • Patent number: 8472244
    Abstract: Spin Torque Transfer (STT) memory cell structures and methods are described herein. One or more STT memory cell structures include a tunneling barrier material positioned between a ferromagnetic storage material and a pinned ferromagnetic material in contact with an antiferromagnetic material. The tunneling barrier material is a multiferroic material and the antiferromagnetic material, the ferromagnetic storage material, and the pinned ferromagnetic material are positioned between a first electrode and a second electrode.
    Type: Grant
    Filed: October 16, 2012
    Date of Patent: June 25, 2013
    Assignee: Micron Technology, Inc.
    Inventors: Stephen J. Kramer, Gurtej S. Sandhu
  • Patent number: 8472243
    Abstract: Disclosed herein is a storage apparatus including a cell array configured to include storage devices arranged to form an array. Each of the storage device has: a storage layer for storing information as the state of magnetization of a magnetic substance; a fixed-magnetization layer having a fixed magnetization direction; and a tunnel insulation layer sandwiched between the storage layer and the fixed-magnetization layer. In an operation to write information on the storage layer, a write current is generated to flow in the layer-stacking direction of the storage layer and the fixed-magnetization layer in order to change the direction of the magnetization of the storage layer. The cell array is divided into a plurality of cell blocks. The thermal stability of the storage layer of any particular one of the storage devices has a value peculiar to the cell block including the particular storage device.
    Type: Grant
    Filed: June 7, 2011
    Date of Patent: June 25, 2013
    Assignee: Sony Corporation
    Inventors: Yutaka Higo, Hiroyuki Uchida, Hiroyuki Ohmori, Kazuhiro Bessho, Masanori Hosomi, Kazutaka Yamane
  • Patent number: 8467227
    Abstract: A non-volatile memory device includes a first electrode, a resistive switching material stack overlying the first electrode. The resistive switching material stack comprising a first resistive switching material and a second resistive switching material. The second resistive switching material overlies the first electrode and the first resistive switching material overlying the second resistive switching material. The first resistive switching material is characterized by a first switching voltage having a first amplitude. The second resistive switching material is characterized by a second switching voltage having a second amplitude no greater than the first switching voltage. A second electrode comprising at least a metal material physically and electrically in contact with the first resistive switching material overlies the first resistive switching material.
    Type: Grant
    Filed: November 4, 2011
    Date of Patent: June 18, 2013
    Assignee: Crossbar, Inc.
    Inventor: Sung Hyun Jo
  • Patent number: 8467234
    Abstract: A magnetic random access memory cell includes a sense layer, a storage layer, and a spacer layer disposed between the sense layer and the storage layer. During a write operation, the storage layer has a magnetization direction that is switchable between m directions to store data corresponding to one of m logic states, with m>2. During a read operation, the sense layer has a magnetization direction that is varied, relative to the magnetization direction of the storage layer, to determine the data stored by the storage layer.
    Type: Grant
    Filed: February 8, 2011
    Date of Patent: June 18, 2013
    Assignee: Crocus Technology Inc.
    Inventors: Neal Berger, Mourad El Baraji
  • Patent number: 8462544
    Abstract: Spin current generators and systems and methods for employing spin current generators. A spin current generator may be configured to generate a spin current polarized in one direction, or a spin current selectively polarized in two directions. The spin current generator may by employed in spintronics applications, wherein a spin current is desired.
    Type: Grant
    Filed: July 23, 2012
    Date of Patent: June 11, 2013
    Assignee: Micron Technology, Inc.
    Inventors: Jun Liu, Gurtej Sandhu
  • Patent number: 8462539
    Abstract: A resistive memory element that includes an element body and at least a pair of electrodes opposed to each other with at least a portion of the element body interposed therebetween. The element body is made of an oxide semiconductor which has a composition represented by the general formula: (Ba1-xSrx)Ti1-yMyO3 (wherein M is at least one from among Mn, Fe, and Co; 0?x?1.0; and 0.005?y?0.05). The first electrode of the pair of electrodes is made of a material which can form a Schottky barrier which can develop a rectifying property and resistance change characteristics in an interface region between the first electrode and the element body. The second electrode is made of a material which provides a more ohmic junction to the element body as compared with the first electrode.
    Type: Grant
    Filed: August 18, 2011
    Date of Patent: June 11, 2013
    Assignee: Murata Manufacturing Co., Ltd.
    Inventor: Sakyo Hirose
  • Patent number: 8462543
    Abstract: Methods of writing to a multi-bit MRAM memory unit are described. The method includes to self-detected writing to a multi-bit (i.e., multilevel) thermally assisted MRAM. The self-detected writing increases a reading margin between data state levels and decreases reading margin variability due to cell resistance variation.
    Type: Grant
    Filed: May 18, 2012
    Date of Patent: June 11, 2013
    Assignee: Seagate Technology LLC
    Inventors: Yuankai Zheng, Dimitar V. Dimitrov, Haiwen Xi
  • Patent number: 8456895
    Abstract: A mechanism is provided for bidirectional writing. A structure includes a reference layer on top of a tunnel barrier, a free layer underneath the tunnel barrier, a metal spacer underneath the free layer, an insulating magnet underneath the metal spacer, and a high resistance layer underneath the insulating layer. The high resistance layer acts as a heater in which the heater heats the insulating magnet to generate spin polarized electrons. A magnetization of the free layer is destabilized by the spin polarized electrons generated from the insulating magnet. A voltage is applied to change the magnetization of the free layer when the magnetization is destabilized. A polarity of the voltage determines when the magnetization of the free layer is parallel and antiparallel to a magnetization of the reference layer.
    Type: Grant
    Filed: May 3, 2011
    Date of Patent: June 4, 2013
    Assignee: International Business Machines Corporation
    Inventors: David W. Abraham, Niladri N. Mojumder, Daniel C. Worledge
  • Patent number: 8456897
    Abstract: A multi-state current-switching magnetic memory element has a magnetic tunneling junction (MTJ), for storing more than one bit of information. The MTJ includes a fixed layer, a barrier layer, and a non-uniform free layer. In one embodiment, having 2 bits per cell, when one of four different levels of current is applied to the memory element, the applied current causes the non-uniform free layer of the MTJ to switch to one of four different magnetic states. The broad switching current distribution of the MTJ is a result of the broad grain size distribution of the non-uniform free layer.
    Type: Grant
    Filed: August 24, 2011
    Date of Patent: June 4, 2013
    Assignee: Avalanche Technology, Inc.
    Inventors: Rajiv Yadav Ranjan, Parviz Keshtbod, Roger Klas Malmhall
  • Patent number: 8456902
    Abstract: The use of diamond-shaped graphene nano-patches as novel non-volatile switching elements exhibiting transitions between high and low conductance states based on changes of magnetic ordering of these states. Non-magnetic reconstructed graphene nano-ribbons are used as non-invasive leads to implement the switching elements as carbon-nanoflake based memories and transistors. Switching of the elements may be implemented by electric-field-induced altering of the magnetic state. Graphene nano-patch shapes of certain geometries provide passive electric-field sources such as to establish initial bits of information saved in graphene-based memories.
    Type: Grant
    Filed: April 27, 2010
    Date of Patent: June 4, 2013
    Assignee: The University Corporation Inc. at California State University Northridge
    Inventors: Nicholas G. Kioussis, Luis A. Agapito
  • Patent number: 8455965
    Abstract: An electronic device manufacturing process includes depositing a bottom electrode layer. Then an electronic device is fabricated on the bottom electrode layer. Patterning of the bottom electrode layer is performed after fabricating the electronic device and in a separate process from patterning a top electrode. A first dielectric layer is then deposited on the electronic device and the bottom electrode layer followed by a top electrode layer. The top electrode is then patterned in a separate process from the bottom electrode. Separately patterning the top and bottom electrodes improves yields by reducing voids in the dielectric material between electronic devices. One electronic device the manufacturing process is well-suited for is magnetic tunnel junctions (MTJs).
    Type: Grant
    Filed: November 30, 2009
    Date of Patent: June 4, 2013
    Assignee: QUALCOMM Incorporated
    Inventors: Xia Li, Seung H. Kang
  • Patent number: 8456888
    Abstract: A semiconductor memory device with a variable resistance element includes a plurality of active areas isolated from one another by an isolation layer formed in a substrate, a plurality of word lines crossing over the plurality of active areas, an auxiliary source line disposed between two selected word lines and commonly connected to at least two active areas among the plurality of active areas between the two selected word lines, and a plurality of contact plugs each connected to a corresponding active area.
    Type: Grant
    Filed: October 7, 2010
    Date of Patent: June 4, 2013
    Assignee: Hynix Semiconductor Inc.
    Inventor: Seung Hyun Lee
  • Patent number: 8455117
    Abstract: A method of producing bit-patterned media is provided whereby a shell structure is added on a bit-patterned media dot. The shell may be an antiferromagnetic material that will help stabilize the magnetization configuration at the remanent state due to exchange coupling between the dot and its shell. Therefore, this approach also improves the thermal stability of the media dot and helps each individual media dot maintain a single domain state.
    Type: Grant
    Filed: March 4, 2009
    Date of Patent: June 4, 2013
    Assignee: Seagate Technology LLC
    Inventors: Kaizhong Gao, Haiwen Xi, Song Xue
  • Patent number: 8456899
    Abstract: A method for operating a memory array device, includes initiating a write “0” state in the device, wherein the initiating the write “0” state includes inducing a first voltage in a word line of the device; and inducing a second voltage in a first bit line (BLTE) of the device.
    Type: Grant
    Filed: July 26, 2012
    Date of Patent: June 4, 2013
    Assignee: International Business Machines Corporation
    Inventors: John K. DeBrosse, Yutaka Nakamura
  • Patent number: 8456893
    Abstract: A MTJ that minimizes spin-transfer magnetization switching current (Jc) in a Spin-RAM to <1×106 A/cm2 is disclosed. The MTJ has a Co60Fe20B20/MgO/Co60Fe20B20 configuration where the CoFeB AP1 pinned and free layers are amorphous and the crystalline MgO tunnel barrier is formed by a ROX or NOX process. The capping layer preferably is a Hf/Ru composite where the lower Hf layer serves as an excellent oxygen getter material to reduce the magnetic “dead layer” at the free layer/capping layer interface and thereby increase dR/R, and lower He and Jc. The annealing temperature is lowered to about 280° C. to give a smoother CoFeB/MgO interface and a smaller offset field than with a 350° C. annealing. In a second embodiment, the AP1 layer has a CoFeB/CoFe configuration wherein the lower CoFeB layer is amorphous and the upper CoFe layer is crystalline to further improve dR/R and lower RA to ?10 ohm/?m2.
    Type: Grant
    Filed: September 15, 2009
    Date of Patent: June 4, 2013
    Assignee: MagIC Technologies, Inc.
    Inventors: Cheng T. Horng, Ru-Ying Tong
  • Patent number: 8456901
    Abstract: A system includes a processor and a memory array connected to the processor comprising a first memory cell comprising a first magnetic tunnel junction device having a first terminal connected to a first bit line and a second terminal, and a first field effect transistor having a source terminal connected to a second bit line, a gate terminal connected to a word line, and a drain terminal connected to the second terminal of the first magnetic tunnel junction device, and a second memory cell comprising a second magnetic tunnel junction device having a first terminal connected to a third bit line and a second terminal, and a second field effect transistor having a source terminal connected to the second bit line, a gate terminal connected to the word line, and a drain terminal connected to the second terminal of the second magnetic tunnel junction device.
    Type: Grant
    Filed: July 27, 2012
    Date of Patent: June 4, 2013
    Assignee: International Business Machines Corporation
    Inventors: John K. DeBrosse, Yutaka Nakamura
  • Patent number: 8456894
    Abstract: A mechanism is provided for noncontact writing. Multiple magnetic islands are provided on a nonmagnetic layer. A reference layer is provided under the nonmagnetic layer. A spin-current is caused to write a state to a magnetic island of the multiple magnetic islands by moving a heat source to heat the magnetic island.
    Type: Grant
    Filed: May 3, 2011
    Date of Patent: June 4, 2013
    Assignee: International Business Machines Corporation
    Inventors: David W. Abraham, Jonathan Z. Sun, Guohan Hu
  • Patent number: 8456882
    Abstract: A method and system for providing a magnetic junction usable in a magnetic memory are described. The magnetic junction includes first and second pinned layers, first and second nonmagnetic spacer layers, and a free layer. The first pinned layer has a first pinned layer magnetic moment and is nonmagnetic layer-free. The first nonmagnetic spacer layer resides between the first pinned and free layers. The free layer resides between the first and second nonmagnetic spacer layers. The second pinned layer has a second pinned layer magnetic moment and is nonmagnetic layer-free. The second nonmagnetic spacer layer resides between the free and second pinned layers. The first and second pinned layer magnetic moments are antiferromagnetically coupled and self-pinned. The magnetic junction is configured to allow the free layer to be switched between stable magnetic states when a write current is passed through the magnetic junction.
    Type: Grant
    Filed: March 8, 2012
    Date of Patent: June 4, 2013
    Assignee: Grandis, Inc.
    Inventors: Dmytro Apalkov, Vladimir Nikitin, David Druist, Steven M. Watts
  • Patent number: 8456883
    Abstract: CMOS devices are provided in a substrate having a topmost metal layer comprising metal landing pads and metal connecting pads. A plurality of magnetic tunnel junction (MTJ) structures are provided over the CMOS devices and connected to the metal landing pads. The MTJ structures are covered with a dielectric layer that is polished until the MTJ structures are exposed. Openings are etched in the dielectric layer to the metal connecting pads. A seed layer is deposited over the dielectric layer and on inside walls and bottom of the openings. A copper layer is plated on the seed layer until the copper layer fills the openings. The copper layer is etched back and the seed layer is removed. Thereafter, an aluminum layer is deposited over the dielectric layer, contacting both the copper layer and the MTJ structures, and patterned to form a bit line.
    Type: Grant
    Filed: May 29, 2012
    Date of Patent: June 4, 2013
    Assignee: Headway Technologies, Inc.
    Inventor: Daniel Liu
  • Patent number: 8456896
    Abstract: A magnetic memory element having a memory cell of size 4F2 is provided that realizes a crosspoint-type memory. In the magnetic memory element, a first magnetic layer, a third magnetic layer (spin polarization enhancement layer), an intermediate layer, a fourth magnetic layer (spin polarization enhancement layer), and a second magnetic layer are stacked in order. The intermediate layer is made of an insulating material or a nonmagnetic material. The second magnetic layer is composed of a ternary alloy of gadolinium, iron and cobalt, a binary alloy of gadolinium and cobalt, or a binary alloy of terbium and cobalt. Alternatively, the first magnetic layer is composed of a ternary alloy of terbium, iron and cobalt, or a binary alloy of terbium and cobalt.
    Type: Grant
    Filed: June 21, 2011
    Date of Patent: June 4, 2013
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Michiya Yamada, Yasushi Ogimoto
  • Patent number: 8451681
    Abstract: A semiconductor storage device includes a memory cell array having memory cells positioned at respective intersections between a plurality of first wirings and a plurality of second wirings, each of the memory cells having a rectifier element and a variable resistance element connected in series, and a control circuit selectively driving the first and second wirings. The control circuit applies a first voltage to the selected first wiring and applies a second voltage to the selected second wiring to apply a certain potential difference to a selected memory cell positioned at a intersection between the selected first and second wirings, and brings at least one of nonselected first wirings into a floating state.
    Type: Grant
    Filed: December 1, 2011
    Date of Patent: May 28, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Hiroshi Maejima
  • Patent number: 8446757
    Abstract: A memory array device comprising a first memory cell comprising a first magnetic tunnel junction device having a first terminal connected to a first bit line (BLTE) and a second terminal, and a first field effect transistor (FET) having a source terminal connected to a second bit line (BLC), a gate terminal connected to a word line (WL), and a drain terminal connected to the second terminal of the first magnetic tunnel junction device, and a second memory cell comprising, a second magnetic tunnel junction device having a first terminal connected to a third bit line (BLT0) and a second terminal, and a second field effect transistor (FET) having a source terminal connected to the second bit line (BLC), a gate terminal connected to the word line (WL), and a drain terminal connected to the second terminal of the second magnetic tunnel junction device.
    Type: Grant
    Filed: August 18, 2010
    Date of Patent: May 21, 2013
    Assignee: International Business Machines Corporation
    Inventors: John K. DeBrosse, Yutaka Nakamura
  • Patent number: 8445979
    Abstract: A magnetic memory device may include a first vertical magnetic layer, a non-magnetic layer on the first vertical magnetic layer, and a first junction magnetic layer on the non-magnetic layer, with the non-magnetic layer being between the first vertical magnetic layer and the first junction magnetic layer. A tunnel barrier may be on the first junction magnetic layer, with the first junction magnetic layer being between the non-magnetic layer and the tunnel barrier. A second junction magnetic layer may be on the tunnel barrier with the tunnel barrier being between the first and second junction magnetic layers, and a second vertical magnetic layer may be on the second junction magnetic layer with the second junction magnetic layer being between the tunnel barrier and the second vertical magnetic layer.
    Type: Grant
    Filed: August 24, 2010
    Date of Patent: May 21, 2013
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Sechung Oh, Jangeun Lee, Jeahyoung Lee, Woojin Kim, Woo Chang Lim, Junho Jeong, Sukhun Choi
  • Patent number: 8446753
    Abstract: A method of selecting a reference circuit for a write operation is disclosed. The method comprises selecting a reference circuit for a write operation based on an output of a row decode circuit and a column decode circuit. The reference circuit is programmed concurrently with a write operation of at least one of a plurality of memory cells in a memory array without requiring an external reference circuit write command.
    Type: Grant
    Filed: March 25, 2010
    Date of Patent: May 21, 2013
    Assignee: QUALCOMM Incorporated
    Inventors: Jung Pill Kim, Hari M. Rao, Xia Li
  • Patent number: 8446761
    Abstract: A method and system for providing a magnetic junction usable in a magnetic device are described. The magnetic junction includes a pinned layer, a plurality of nonmagnetic spacer layers, and a plurality of free layers. The free layers are interleaved with the nonmagnetic spacer layers. A first nonmagnetic spacer layer of the nonmagnetic spacer layers is between the free layers and the pinned layer. Each of the free layers is configured to be switchable between stable magnetic states when a write current is passed through the magnetic junction. Each of the free layers has a critical switching current density. The critical switching current density of one of the free layers changes monotonically from the critical switching current density of an adjacent free layer. The adjacent free layer is between the pinned layer and the one of the plurality of free layers.
    Type: Grant
    Filed: February 18, 2011
    Date of Patent: May 21, 2013
    Assignee: Grandis, Inc.
    Inventors: Dmytro Apalkov, Xueti Tang, Vladimir Nikitin, Alexander A. G. Driskill-Smith
  • Patent number: 8441850
    Abstract: A large scale memory array includes a uniform pattern of uniformly sized dummy bit cells and active bit cells. Sub-arrays within the large scale memory array are separated by the dummy bit cells. Signal distribution circuitry is formed with a width or height corresponding to the width or height of the dummy bit cells so that the signal distribution circuitry occupies the same footprint as the dummy bit cells without disrupting the uniform pattern across the large scale array. Edge dummy cells of a similar size or larger than the standard size bit cells may be placed around the edge of the large scale array to further reduce pattern loading affects.
    Type: Grant
    Filed: October 8, 2010
    Date of Patent: May 14, 2013
    Assignee: QUALCOMM Incorporated
    Inventors: Kangho Lee, Tae Hyun Kim, Xia Li, Jung Pill Kim, Seung H. Kang
  • Patent number: 8443318
    Abstract: The junction comprising a stack of at least two magnetic layers, a first layer, for example a soft magnetic layer with controllable magnetization, and a second layer, for example a hard magnetic layer with fixed magnetization, the magnetization of the soft layer being described by a uniform magnetic moment, the dynamic behavior of the junction being modeled by an equivalent electrical circuit comprising at least two coupled parts: a first part representing the stack of the layers, through which a current flows corresponding to the polarized current flowing through said layers whose resistance across its terminals depends on three voltages representing the three dimensions of the magnetic moment along three axes, modeling the tunnel effect; a second part representing the behavior of the magnetic moment, comprising three circuits each representing a dimension of the magnetic moment by the three voltages, each of the three voltages depending on the voltages in the other dimensions and on the voltage across the t
    Type: Grant
    Filed: December 16, 2008
    Date of Patent: May 14, 2013
    Assignees: Commissariat a l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique
    Inventors: Guillaume Prenat, Wei Guo
  • Patent number: 8441844
    Abstract: A method of writing in a memory device comprising a plurality of MRAM cells, each cell including a magnetic tunnel junction having a resistance that can be varied during a write operation when heated at a high threshold temperature; a plurality of word lines connecting cells along a row; and a plurality of bit lines connecting cells along a column; the method comprising supplying a bit line voltage to one of the bit lines and a word line voltage to one of the word lines for passing a heating current through the magnetic tunnel junction of a selected cell; said word line voltage is a word line overdrive voltage being higher than the core operating voltage of the cells such that the heating current has a magnitude that is high enough for heating the magnetic tunnel junction at the predetermined high threshold temperature. The memory device can be written with low power consumption.
    Type: Grant
    Filed: June 8, 2011
    Date of Patent: May 14, 2013
    Assignee: Crocus Technology SA
    Inventors: Mourad El Baraji, Neal Berger
  • Patent number: 8440471
    Abstract: A method of flash-RAM memory includes non-volatile random access memory (RAM) formed on a monolithic die and non-volatile page-mode memory formed on top of the non-volatile RAM, the non-volatile page-mode memory and the non-volatile RAM reside on the monolithic die. The non-volatile RAM is formed of stacks of magnetic memory cells arranged in three-dimensional form for higher density and lower costs.
    Type: Grant
    Filed: January 6, 2012
    Date of Patent: May 14, 2013
    Assignee: Avalanche Technology, Inc.
    Inventors: Rajiv Yadav Ranjan, Parviz Keshtbod, Mahmud Assar
  • Publication number: 20130114336
    Abstract: A two-transistor one-MTJ (2T1MTJ) three port structure includes two separate pin layer structures coupled to one free layer structure. The pin layer structures may include an anti-ferromagnetic layer (AFM) layer coupled to a pin layer. The free layer structure includes free layer coupled to a barrier layer and a cap layer. The free layer structure may include a thin barrier layer coupled to each of the pin layer stacks. The three port MTJ structure provides separate write and read paths which improve read sensing margin without increasing write voltage or current. The three port MTJ structure may be fabricated with a simple two step MTJ etch process.
    Type: Application
    Filed: January 24, 2012
    Publication date: May 9, 2013
    Applicant: QUALCOMM Incorporated
    Inventors: Xia Li, Xiaochun Zhu, Seung H. Kang, Jung Pill Kim, Wah Nam Hsu, Taehyun Kim, Kangho Lee
  • Patent number: 8437181
    Abstract: An array of rows and columns of SMT MRAM cells has each of the columns associated with one of its adjacent columns. Each of the SMT MRAM cells of the column is connected to a true data bit line and each of the SMT MRAM cells of the associated pair of columns is connected to a shared complement data bit line. A shunting switch device is connected between each of the true data bit lines and the shared complement data bit line for selectively connecting one of the true data bit lines to the shared complement data bit line to effectively reduce the resistance of the complement data bit line and to eliminate program disturb effects in adjacent non-selected columns of the SMT MRAM cells.
    Type: Grant
    Filed: June 29, 2010
    Date of Patent: May 7, 2013
    Assignees: MagIC Technologies, Inc., International Business Machines Corporation
    Inventors: Hsu Kai Yang, Yutaka Nakamura, John Debrosse
  • Patent number: 8435652
    Abstract: A magnetic stack structure is disclosed. The magnetic stack structure includes two metal layers and a free layer sandwiched by the two metal layers. The thickness of the free layer is 1-30 nm. The thickness of the metal layers are 0.1-20 nm respectively.
    Type: Grant
    Filed: July 9, 2009
    Date of Patent: May 7, 2013
    Assignee: National Yunlin University of Science and Technology
    Inventors: Te-Ho Wu, Lin-Hsiu Ye, Ching-Ming Lee
  • Patent number: 8437180
    Abstract: A memory includes: a memory device that has a memory layer storing data as a magnetization state of a magnetic body and a magnetization fixed layer whose direction of magnetization is fixed through a nonmagnetic layer interposed between the memory layer and the magnetization fixed layer and stores the data in the memory layer by changing a magnetization direction of the memory layer when a write current flowing in a stacked direction of the memory layer and the magnetization fixed layer is applied; and a voltage control unit that supplies the write current configured by independent pulse trains of two or more to the memory device by using a write voltage that is configured by independent pulse trains of two or more.
    Type: Grant
    Filed: June 8, 2010
    Date of Patent: May 7, 2013
    Assignee: Sony Corporation
    Inventors: Yutaka Higo, Masanori Hosomi, Minoru Ikarashi, Hiroshi Kano, Shinichiro Kusunoki, Hiroyuki Ohmori, Yuki Oishi, Kazutaka Yamane, Tetsuya Yamamoto, Kazuhiro Bessho
  • Patent number: 8432731
    Abstract: A method, system, and apparatus magnetically coupled electrostatically shiftable memory device and method are disclosed. In one embodiment, a method includes electrostatically decoupling a separate structure and a surface that are magnetically coupled (e.g., an electrostatic force to decouple the separate structure and the surface is generated with an electrode), shifting the separate structure between the surface and a other surface with the electrostatic force (e.g., shifting the separate structure moves the entire separate structure), and magnetically coupling the separate structure to the other surface.
    Type: Grant
    Filed: September 29, 2008
    Date of Patent: April 30, 2013
    Inventors: Sridhar Kasichainula, Kishore Kasichainula, Mike Daneman
  • Patent number: 8432727
    Abstract: In a Spin Transfer Torque Magnetoresistive Random Access Memory (STT-MRAM) a bit cell array can have a source line substantially parallel to a word line. The source line can be substantially perpendicular to bit lines. A source line control unit includes a common source line driver and a source line selector configured to select individual ones of the source lines. The source line driver and source line selector can be coupled in multiplexed relation. A bit line control unit includes a common bit line driver and a bit line selector in multiplexed relation. The bit line control unit includes a positive channel metal oxide semiconductor (PMOS) element coupled between the common source line driver and bit line select lines and bit lines.
    Type: Grant
    Filed: April 29, 2010
    Date of Patent: April 30, 2013
    Assignees: QUALCOMM Incorporated, Industry-Academic Cooperation Foundation, Yonsei
    Inventors: Kyungho Ryu, Jisu Kim, Seong-Ook Jung, Seung H. Kang
  • Patent number: 8432009
    Abstract: A method and system for providing a magnetic junction usable in a magnetic device are described. The magnetic junction includes a pinned layer, a nonmagnetic spacer layer, and a free layer. The nonmagnetic spacer layer is between the pinned layer and the free layer. The magnetic junction is configured such that the free layer is switchable between a plurality of stable magnetic states when a write current is passed through the magnetic junction. At least one of the pinned layer and the free layer includes a magnetic substructure. The magnetic substructure includes at least two magnetic layers interleaved with at least one insertion layer. Each insertion layer includes at least one of Cr, Ta, Ti, W, Ru, V, Cu, Mg, aluminum oxide, and MgO. The magnetic layers are exchange coupled.
    Type: Grant
    Filed: January 21, 2011
    Date of Patent: April 30, 2013
    Assignee: Grandis, Inc.
    Inventors: Dmytro Apalkov, Xueti Tang, Vladimir Nikitin
  • Patent number: 8432728
    Abstract: A magnetic recording element is disclosed for which current density required for writing is low and structure of the element is simple. It comprises a ferromagnetic fine wire formed on a Si substrate, current electrodes that contact ends of the ferromagnetic fine wire, and voltage electrodes joined to the ferromagnetic fine wire and current electrodes to measure voltage across part of the ferromagnetic fine wire in cooperation with the current electrodes. A magnetic domain wall is induced in the ferromagnetic fine wire when the element is manufactured. A depression is formed in the surface on top of the ferromagnetic fine wire between the voltage electrodes, and between one of the current electrodes and one of the voltage electrodes. Voltage is measured between the two voltage electrodes when reading current is applied, to determine whether the magnetic domain wall is present between the two voltage electrodes, whereby recorded data can be identified.
    Type: Grant
    Filed: September 19, 2011
    Date of Patent: April 30, 2013
    Assignee: Fuji Electric Co., Ltd.
    Inventor: Takuya Ono
  • Patent number: 8427864
    Abstract: To write information on a memory cell of SPRAM formed of an MOS transistor and a tunnel magnetoresistive element, the memory cell is supplied with a current in a direction opposite to a direction of a current required for writing the information on the memory cell, and then, the memory cell is supplied with a current required for writing. In this manner, even when the same information is sequentially written on the memory cell, since the currents in the two directions are caused to flow in pairs in the tunnel magnetoresistive element of the memory cell each time information is rewritten, deterioration of a film that forms the tunnel magnetoresistive element can be suppressed. Therefore, reliability of the SPRAM can be improved.
    Type: Grant
    Filed: June 2, 2010
    Date of Patent: April 23, 2013
    Assignee: Hitachi, Ltd.
    Inventors: Takayuki Kawahara, Kiyoo Itoh, Riichiro Takemura, Kenchi Ito