Including Magnetic Element Patents (Class 365/230.07)
  • Patent number: 9466030
    Abstract: Embodiments of the invention relate to implementing a probabilistic graphical model (PGM) using magnetic tunnel junctions (MTJs). One embodiment comprises a memory array of magnetic tunnel junctions and a driver unit for programming the memory array to represent a probabilistic graphical model. The magnetic tunnel junctions are organized into multiple subsets of magnetic tunnel junctions. The driver unit selectively applies an electrical pulse to a subset of magnetic tunnel junctions to program information representing a probabilistic belief state in said subset of magnetic tunnel junctions.
    Type: Grant
    Filed: August 30, 2012
    Date of Patent: October 11, 2016
    Assignee: International Business Machines Corporation
    Inventors: Bryan L. Jackson, Dharmendra S. Modha
  • Patent number: 9434622
    Abstract: A sintered ferrite material, which is obtained by adding Bi2O3 in a range from 0.5% by mass to 3% by mass against 100% by mass of a material having a composition formula of (1-x-y-z)(Li0.5Fe0.5)O.xZnO.yFe2O3.zCuO wherein x, y and z satisfy 0.14?x?0.19, 0.48?y<0.5 and 0?z?0.03 and satisfies resistivity equal to or higher than 106 ?m, initial permeability equal to or higher than 200 and saturation magnetic flux density equal to or higher than 430 mT at 23° C. and equal to or higher than 380 mT at 100° C.
    Type: Grant
    Filed: February 13, 2009
    Date of Patent: September 6, 2016
    Assignee: Hitachi Metals, Ltd.
    Inventors: Tomoyuki Tada, Yasuharu Miyoshi
  • Patent number: 8953368
    Abstract: A data reading method of a magnetic memory device includes generating read commands, supplying a read current to a selected magnetic memory element in a first direction and in turn in a second direction under different ones of the read commands, respectively, and sensing the magnitude of the read current flowing through the selected magnetic memory element to read data stored at the selected magnetic memory element.
    Type: Grant
    Filed: August 15, 2013
    Date of Patent: February 10, 2015
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Soo-Ho Cha
  • Patent number: 8947972
    Abstract: A non-volatile memory system evaluates user data before writing in order to potentially group addresses for writing within a cycle. The system can determine which sense amplifier addresses of a column address will be programmed in a column address cycle. The number of bits that will be programmed is compared with an allowable number of parallel bits. The system generates groups of sense amplifier addresses based on the comparison. The system generates groups that include a total number of bits to be programmed that is within the allowable number of parallel bits. Each group is programmed in one sense amplifier address cycle. Multiple sense amplifier addresses can be grouped for programming while still remaining within an allowable number of parallel programming bits. The system performs a read before write operation and generates bitmap data for the grouping information corresponding sense amplifier addresses.
    Type: Grant
    Filed: March 15, 2013
    Date of Patent: February 3, 2015
    Assignee: SanDisk 3D LLC
    Inventors: Gopinath Balakrishnan, Tz-Yi Liu
  • Patent number: 8693238
    Abstract: An MRAM of a spin transfer type is provided with a memory cell 10 and a word driver 30. The memory cell 10 has a magnetic resistance element 1 and a selection transistor TR having one of source/drain electrodes which is connected with one end of the magnetic resistance element 1. The word driver 30 drives a word line WL connected with a gate electrode of the selection transistor TR. The word driver 30 changes a drive voltage of the word line WL according to the write data DW to be written in the magnetic resistance element 1.
    Type: Grant
    Filed: July 13, 2007
    Date of Patent: April 8, 2014
    Assignee: NEC Corporation
    Inventors: Noboru Sakimura, Takeshi Honda, Tadahiko Sugibayashi
  • Patent number: 8681538
    Abstract: A semiconductor storage device according to the present embodiment includes a plurality of bit lines, a plurality of word lines, and a plurality of memory cells each including a storage element and a switching element which are connected in series between adjacently paired ones of the bit lines. Gates of the switching elements of the memory cells connected between one of the adjacently paired ones of the bit lines are respectively connected to different ones of the word lines. A plurality of the storage elements and a plurality of the switching elements of the adjacent memory cells are alternately connected in series.
    Type: Grant
    Filed: March 20, 2012
    Date of Patent: March 25, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Tsuneo Inaba
  • Patent number: 8625336
    Abstract: A memory device includes magnetic random access memory (“MRAM”) cells that are electrically connected in series, each one of the MRAM cells having a storage magnetization direction and a sense magnetization direction. During a write operation, multiple ones of the MRAM cells are written in parallel by switching the storage magnetization directions of the MRAM cells. During a read operation, a particular one of the MRAM cells is read by varying the sense magnetization direction of the particular one of the MRAM cells, relative to the storage magnetization direction of the particular one of the MRAM cells.
    Type: Grant
    Filed: February 8, 2011
    Date of Patent: January 7, 2014
    Assignee: Crocus Technology Inc.
    Inventors: Neal Berger, Mourad El Baraji
  • 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: 8400867
    Abstract: A method and apparatus for stray magnetic field compensation in a non-volatile memory cell, such as a spin-torque transfer random access memory (STRAM). In some embodiments, a first tunneling barrier is coupled to a reference structure that has a perpendicular anisotropy and a first magnetization direction. A recording structure that has a perpendicular anisotropy is coupled to the first tunneling barrier and a nonmagnetic spacer layer. A compensation layer that has a perpendicular anisotropy and a second magnetization direction in substantial opposition to the first magnetization direction is coupled to the nonmagnetic spacer layer. Further, the memory cell is programmable to a selected resistance state with application of a current to the recording structure.
    Type: Grant
    Filed: December 12, 2011
    Date of Patent: March 19, 2013
    Assignee: Seagate Technology LLC
    Inventors: Dimitar Dimitrov, Olle Gunnar Heinonen, Dexin Wang, Haiwen Xi
  • Patent number: 8279667
    Abstract: Provided are nonvolatile memory devices and program methods thereof, an integrated circuit memory system includes a memory array comprising at least one magnetic track, each of the at least one magnetic track including a plurality of magnetic domains and at least one read/write unit coupled thereto, decoding circuitry coupled to the memory array that is operable to select at least one of the magnetic domains, a read/write controller coupled to the memory array that is operable to read data from at least one of the plurality of magnetic domains and to write data to at least one of the plurality of magnetic domains via the at least one read/write unit coupled to each of the at least one magnetic track, and a domain controller coupled to memory array that is operable to move data between the magnetic domains on each of the at least one magnetic track.
    Type: Grant
    Filed: May 6, 2010
    Date of Patent: October 2, 2012
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Ho Jung Kim, Sang Beom Kang, Chul Woo Park, Hyun Ho Choi, Jong Wan Kim, Young Pill Kim, Sung Chul Lee
  • Patent number: 8159871
    Abstract: A magnetoresistive memory cell includes an MTJ device and a select transistor. The select transistor includes a first conduction-type semiconductor layer, a gate electrode formed by disposing a gate insulating layer on top of the semiconductor layer, and first and second diffusion regions formed in the semiconductor layer to be spaced apart from each other and to have a second conduction type. A part of the semiconductor layer between the first and second diffusion regions is formed as an electrically floating body region. By using a high-performance select transistor with a floating body effect, high integration of a magnetoresistive memory device may be achieved.
    Type: Grant
    Filed: July 22, 2009
    Date of Patent: April 17, 2012
    Assignee: Hynix Semiconductor Inc.
    Inventor: Sung Woong Chung
  • Patent number: 8098541
    Abstract: A method and apparatus for stray magnetic field compensation in a non-volatile memory cell, such as a spin-torque transfer random access memory (STRAM). In some embodiments, a first tunneling barrier is coupled to a reference structure that has a perpendicular anisotropy and a first magnetization direction. A recording structure that has a perpendicular anisotropy is coupled to the first tunneling barrier and a nonmagnetic spacer layer. A compensation layer that has a perpendicular anisotropy and a second magnetization direction in substantial opposition to the first magnetization direction is coupled to the nonmagnetic spacer layer. Further, the memory cell is programmable to a selected resistance state with application of a current to the recording structure.
    Type: Grant
    Filed: April 12, 2011
    Date of Patent: January 17, 2012
    Assignee: Seagate Technology LLC
    Inventors: Dimitar Dimitrov, Olle Gunnar Heinonen, Dexin Wang, Haiwen Xi
  • Patent number: 8077538
    Abstract: Address decoders and access line drivers are provided. One such row decoder and access line driver receives power supply voltages in a manner that prevents CHC damage and avoids GIDL currents in transistors in the decoder and driver. The row decoder and a latch in the driver are powered by a first supply voltage, and an output stage in the access line driver is powered by a second supply voltage. The first and second supply voltages are maintained at a relatively low level during standby before an address is decoded. Only after an address is decoded to set the latch are the supply voltages increased to levels needed to drive the access line. Further, before resetting the latch, the first and power supply voltages are decreased to their standby levels. By maintaining the first and second voltages relatively low until after the latch is set and reset, GIDL currents may be avoided and CHC damage may be prevented.
    Type: Grant
    Filed: July 9, 2010
    Date of Patent: December 13, 2011
    Assignee: Micron Technology, Inc.
    Inventor: Vikram Bollu
  • Patent number: 7961491
    Abstract: Provided are a data storage device using a magnetic domain wall movement and a method of operating the data storage device. The data storage device includes a magnetic layer which has a plurality of magnetic domains, a current applying unit which applies current for a magnetic domain wall movement to the magnetic layer, and a head for reading and writing, wherein the magnetic layer comprises a plurality of perpendicular magnetic layers formed on a substrate in a plurality of rows and columns, and a horizontal magnetic layer formed on the perpendicular magnetic layers to connect the perpendicular magnetic layers.
    Type: Grant
    Filed: March 29, 2007
    Date of Patent: June 14, 2011
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Sung-chul Lee, Sung-hoon Choa, Eun-sik Kim
  • Patent number: 7940600
    Abstract: A method and apparatus for stray magnetic field compensation in a non-volatile memory cell, such as a spin-torque transfer random access memory (STRAM). In some embodiments, a first tunneling barrier is coupled to a reference structure that has a perpendicular anisotropy and a first magnetization direction. A recording structure that has a perpendicular anisotropy is coupled to the first tunneling barrier and a nonmagnetic spacer layer. A compensation layer that has a perpendicular anisotropy and a second magnetization direction in substantial opposition to the first magnetization direction is coupled to the nonmagnetic spacer layer. Further, the memory cell is programmable to a selected resistance state with application of a current to the recording structure.
    Type: Grant
    Filed: December 2, 2008
    Date of Patent: May 10, 2011
    Assignee: Seagate Technology LLC
    Inventors: Dimitar Dimitrov, Olle Gunnar Heinonen, Dexin Wang, Haiwen Xi
  • Publication number: 20110032755
    Abstract: Disclosed is a current driving mechanism for a magnetic memory device, comprising: a) a current driver circuit; and b) a current decoding block coupled to the current driver circuit, wherein the current decoding block comprises a transistor M18 to control driver currents from the current driver circuit, and wherein the transistor M18 has a smaller form factor then otherwise possible by virtue of maintaining a gate thereof at a negative voltage.
    Type: Application
    Filed: August 6, 2010
    Publication date: February 10, 2011
    Applicant: MAGSIL CORPORATION
    Inventors: Krishnakumar Mani, Anil Gupta
  • Patent number: 7773405
    Abstract: A magnetic random access memory includes: a first and second wirings, a plurality of third wirings, a plurality of memory cells and a terminating unit. The first and second wirings extend in a Y direction. The plurality of third wirings extends in an X direction. The memory cell is provided correspondingly to an intersection between the first and second wirings and the third wiring. The terminating unit is provided between the plurality of memory cells and connected to the first and second wirings. The memory cell includes transistors and a magnetoresistive element. The transistors are connected in series between the first and second wirings and controlled based on a signal of the third wiring. The magnetoresistive element is connected to a wiring through which the transistors are connected. At a time of a writing operation, when the write current 1w is supplied from one of the first and second wiring to the other through the transistors, the terminating unit grounds the other.
    Type: Grant
    Filed: June 1, 2007
    Date of Patent: August 10, 2010
    Assignee: NEC Corporation
    Inventors: Noboru Sakimura, Takeshi Honda, Tadahiko Sugibayashi
  • Patent number: 7768865
    Abstract: A row decoder and access line driver receives power supply voltages in a manner that prevents CHC damage and avoids GIDL currents in transistors in the decoder and driver. The row decoder and a latch in the driver are powered by a first supply voltage, and an output stage in the access line driver is powered by a second supply voltage. The first and second supply voltages are maintained at a relatively low level during standby before an address is decoded. Only after an address is decoded to set the latch are the supply voltages increased to levels needed to drive the access line. Further, before resetting the latch, the first and power supply voltages are decreased to their standby levels. By maintaining the first and second voltages relatively low until after the latch is set and reset, GIDL currents may be avoided and CHC damage may be prevented.
    Type: Grant
    Filed: April 21, 2008
    Date of Patent: August 3, 2010
    Inventor: Vikram Bollu
  • Patent number: 7719890
    Abstract: A portion of a nonvolatile memory array that is likely to contain, partially programmed data may be identified from a high sensitivity read, by applying stricter than usual ECC requirements, or using pointers to programmed sectors. The last programmed data may be treated as likely to be partially programmed data. Data in the identified portion may be copied to another location, or left where it is with an indicator to prohibit further programming to the same cells. To avoid compromising previously stored data during subsequent programming, previously stored data may be backed up. Backing up may be done selectively, for example, only for nonsequential data, or only when the previously stored data contains an earlier version of data being programmed. If a backup copy already exists, another backup copy is not created. Sequential commands are treated as a single command if received within a predetermined time period.
    Type: Grant
    Filed: February 5, 2008
    Date of Patent: May 18, 2010
    Assignee: SanDisk Corporation
    Inventors: Sergey A. Gorobets, Shai Traister, Jason T. Lin, Alan D. Bennett, Neil D. Hutchison
  • Patent number: 7567453
    Abstract: An advanced multi-bit magnetic random access memory device and a method for writing to the advanced multi-bit magnetic random access memory device. The magnetic memory includes one or more pair-cells. A pair-cell is two memory cells. Each memory cell has a magnetic multilayer structure. The structure includes a magnetically changeable ferromagnetic layer, a ferromagnetic reference layer having a non-changeable magnetization state, and a corresponding spacer layer separating the ferromagnetic layers. The memory cells are arranged such that an effective remnant magnetization of each of the cells is non-parallel from the cells' long-axis. This allows for more than one-bit to be stored as well as for efficient writing and reduced power consumption.
    Type: Grant
    Filed: January 9, 2008
    Date of Patent: July 28, 2009
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Chee-kheng Lim
  • Patent number: 7518919
    Abstract: In order to maintain the integrity of data stored in a flash memory that are susceptible to being disturbed by operations in adjacent regions of the memory, disturb events cause the data to be read, corrected and re-written before becoming so corrupted that valid data cannot be recovered. The sometimes conflicting needs to maintain data integrity and system performance are balanced by deferring execution of some of the corrective action when the memory system has other high priority operations to perform. In a memory system utilizing very large units of erase, the corrective process is executed in a manner that is consistent with efficiently rewriting an amount of data much less than the capacity of a unit of erase.
    Type: Grant
    Filed: May 14, 2007
    Date of Patent: April 14, 2009
    Assignee: Sandisk Corporation
    Inventors: Carlos J. Gonzalez, Kevin M. Conley
  • Patent number: 7477567
    Abstract: A memory storage device is provided that includes a storage cell having a changeable magnetic region. The changeable magnetic region includes a material having a magnetization state that is responsive to a change in temperature. The memory storage device also includes a heating element. The heating element is proximate to the storage cell for selectively changing the temperature of the changeable magnetic region of said storage cell. By heating the storage cell via the heating element, as opposed to heating the storage cell by directly applying current thereto, more flexibility is provided in the manufacture of the storage cells.
    Type: Grant
    Filed: July 8, 2003
    Date of Patent: January 13, 2009
    Assignee: International Business Machines Corporation
    Inventors: David W. Abraham, Philip L. Trouilloud
  • Publication number: 20080304353
    Abstract: A memory storage device is provided that includes a storage cell having a changeable magnetic region. The changeable magnetic region includes a material having a magnetization state that is responsive to a change in temperature. The memory storage device also includes a heating element. The heating element is proximate to the storage cell for selectively changing the temperature of the changeable magnetic region of said storage cell. By heating the storage cell via the heating element, as opposed to heating the storage cell by directly applying current thereto, more flexibility is provided in the manufacture of the storage cells.
    Type: Application
    Filed: July 8, 2003
    Publication date: December 11, 2008
    Inventors: David W. Abraham, Philip L. Trouilloud
  • Patent number: 7345945
    Abstract: A semiconductor memory device having a word line driver circuit configured in stages. A plurality of sub word line driver circuits are connected, in parallel, to each main word line, and provide a sub word line enable signal to a selected sub word line in response to a main word line enable signal provided through a main word line. A plurality of (local) word line driver circuits are connected in parallel, to each sub word line and provide a local word line enable signal to a selected local word line in response to the (main/sub) word line enable signal so as to operate a plurality of memory cells connected to the selected local word line. The transistor count and layout area of a semiconductor memory device decreases and a reduced chip area can be achieved.
    Type: Grant
    Filed: September 21, 2005
    Date of Patent: March 18, 2008
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Byung-Gil Jeon, Byung-Jun Min, Kang-Woon Lee, Han-Joo Lee
  • Patent number: 7336528
    Abstract: An advanced multi-bit magnetic random access memory device and a method for writing to the advanced multi-bit magnetic random access memory device. The magnetic memory includes one or more pair-cells. A pair-cell is two memory cells. Each memory cell has a magnetic multilayer structure. The structure includes a magnetically changeable ferromagnetic layer, a ferromagnetic reference layer having a non-changeable magnetization state, and a corresponding spacer layer separating the ferromagnetic layers. The memory cells are arranged such that an effective remnant magnetization of each of the cells is non-parallel from the cells' long-axis. This allows for more than one-bit to be stored as well as for efficient writing and reduced power consumption.
    Type: Grant
    Filed: April 29, 2005
    Date of Patent: February 26, 2008
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Chee-kheng Lim
  • Patent number: 7196955
    Abstract: An exemplary magnetic random access memory comprises a plurality of hardmasks, a plurality of magnetic memory elements each having been formed using a corresponding one of the hardmasks, and at least one conductor near the hardmasks. The conductor is capable of carrying a current to generate radio frequency electromagnetic fields absorbable by the hardmasks to heat the hardmasks to elevate the temperature of one or more of the magnetic memory elements to thermally assist in switching a magnetic orientation thereof.
    Type: Grant
    Filed: January 12, 2005
    Date of Patent: March 27, 2007
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventor: Janice H. Nickel
  • Patent number: 7158397
    Abstract: Line drivers that fit within a specified line pitch. One method of placing line drivers completely underneath a cross point array requires splitting the line driver up so that a portion of the line drivers is on a first side of the cross point array and the other portion is on the opposite side. However, using this technique requires that the width of the drivers is no larger than the width of the memory cells that are being driven. This can be accomplished by stacking transistors such that line drivers fit within a specified line pitch, but are as long as is necessary to include all the necessary circuitry.
    Type: Grant
    Filed: April 14, 2005
    Date of Patent: January 2, 2007
    Inventors: Darrell Rinerson, Christophe Chevallier
  • Patent number: 7072207
    Abstract: For writing K-bit write data in parallel (K is integer at least 2), bit lines each arranged for each memory cell columns and at least K current return lines are provided. K selected bit lines to write the K-bit write data are connected in series in a single current path. When data having different levels are written through adjacent selected bit lines, the selected bit lines are connected to each other at their one ends or the other ends, so that a bit line write current flowing through the former selected bit line is directly transmitted to the latter selected bit line. On the other hand, when data having the same level are written through adjacent selected bit lines, a bit line write current flowing through the former selected bit line is turned back by the corresponding current return line, and then transmitted to the latter selected bit line.
    Type: Grant
    Filed: February 13, 2004
    Date of Patent: July 4, 2006
    Assignee: Renesas Technology Corp.
    Inventor: Tsukasa Ooishi
  • Patent number: 7038939
    Abstract: The magnetic memory includes a plurality of memory cells, each memory cell including: at least one writing wire; at least one data storage portion, provided on at least one portion of an outer periphery of the writing wire, which comprises a ferromagnetic material whose magnetization direction can be inverted by causing a current to flow in the writing wire; and at least one magneto-resistance effect element, disposed in the vicinity of the data storage portion, which senses the magnetization direction of the data storage portion.
    Type: Grant
    Filed: October 30, 2003
    Date of Patent: May 2, 2006
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Minoru Amano, Tatsuya Kishi, Sumio Ikegawa, Yoshiaki Saito, Hiroaki Yoda
  • Patent number: 7003622
    Abstract: A semiconductor memory includes a redundant RAM disposed independently of at least one regular RAM, the redundant RAM having redundant memory elements by which defective memory elements of the regular RAM can be replaced, and a control block for selecting either at least the regular RAM or the redundant RAM according to an address applied thereto, and for reading data from a memory cell of the selected RAM specified by the address. A plurality of regular RAMs can be disposed and the redundant RAM includes redundant memory elements by which defective memory elements of an arbitrary one of the plurality of regular RAMs can be replaced. The control block selects either one of the plurality of regular RAMs or the redundant RAM according to an address applied thereto, and reads data from a memory cell of the selected RAM specified by the address.
    Type: Grant
    Filed: June 12, 2002
    Date of Patent: February 21, 2006
    Assignee: Renesas Technology Corp.
    Inventors: Hirofumi Shinohara, Yoshiki Tsujihashi, Takeshi Hashizume
  • Patent number: 6975555
    Abstract: A magnetic random access memory circuit comprises a plurality of magnetic memory cells, each of the memory cells including a magnetic storage element having an easy axis and a hard axis associated therewith, and a plurality of column lines and row lines for selectively accessing one or more of the memory cells, each of the memory cells being proximate to an intersection of one of the column lines and one of the row lines. Each of the magnetic memory cells is arranged such that the easy axis is substantially parallel to a direction of flow of a sense current and the hard axis is substantially parallel to a direction of flow of a write current.
    Type: Grant
    Filed: October 29, 2004
    Date of Patent: December 13, 2005
    Assignee: International Business Machines Corporation
    Inventors: Yu Lu, William Robert Reohr, Roy Edwin Scheuerlein
  • Patent number: 6950369
    Abstract: A plurality of word lines (WL1) are provided in parallel to one another and a plurality of bit lines (BL1) are provided in parallel to one another, intersecting the word lines (WL1) thereabove. MRAM cells (MC2) are formed at intersections of the word lines and the bit lines therebetween. MRAM cells (MC3) are provided so that an easy axis indicated by the arrow has an angle of 45 degrees with respect to the bit lines and the word lines. Thus, an MRAM capable of cutting the power consumption in writing is achieved and further an MRAM capable of reducing the time required for erasing and writing operations is achieved.
    Type: Grant
    Filed: March 11, 2004
    Date of Patent: September 27, 2005
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tatsuya Kunikiyo, Katsumi Eikyu
  • Patent number: 6839269
    Abstract: TMR elements are arranged at the intersections between word lines and bit lines. One end of each word line is connected to the ground point through a row select switch. One end of each bit line is connected to a bit line bias circuit. In read operation, the bit line bias circuit applies a bias potential to all the bit lines. The selected word line is short-circuited to the ground point. Unselected word lines are set in a floating state.
    Type: Grant
    Filed: June 27, 2002
    Date of Patent: January 4, 2005
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yoshihisa Iwata, Tomoki Higashi
  • Patent number: 6816431
    Abstract: A magnetic random access memory circuit comprises a plurality of magnetic memory cells, each of the memory cells including a magnetic storage element having an easy axis and a hard axis associated therewith, and a plurality of column lines and row lines for selectively accessing one or more of the memory cells, each of the memory cells being proximate to an intersection of one of the column lines and one of the row lines. Each of the magnetic memory cells is arranged such that the easy axis is substantially parallel to a direction of flow of a sense current and the hard axis is substantially parallel to a direction of flow of a write current.
    Type: Grant
    Filed: May 28, 2003
    Date of Patent: November 9, 2004
    Assignee: International Business Machines Corporation
    Inventors: Yu Lu, William Robert Reohr, Roy Edwin Scheuerlein
  • Patent number: 6807112
    Abstract: In view of the transistor off leakage increasing with device miniaturization, the invention provides a semiconductor integrated circuit capable of high-speed readout by eliminating the need for a charge replenishing transistor formerly required to hold a bit line at the “H” level, and thereby speeding up readout of stored data that causes the bit line to transition to the “L” level. To achieve this, a high-potential source line and a low-potential source line are provided. Then, the source of a memory cell is selectively connected to either the high-potential source line and the low-potential source line.
    Type: Grant
    Filed: September 23, 2003
    Date of Patent: October 19, 2004
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventor: Mitsuaki Hayashi
  • Patent number: 6778432
    Abstract: A thin film magnetic memory device includes a plurality of program cells each storing program data constituting information on a bit unit basis, each program cell having a magnetic storing part having first and second electric resistors corresponding to two magnetization directions. The thin film magnetic memory device further includes: a driver circuit for irreversibly fixing a resistance value of the magnetic storing part in the program cell to a third electric resistor; and a sense driver circuit capable of sensing whether the magnetic storing part in the program cell has the first or second electric resistance and capable of sensing whether the magnetic storing part in the program cell has any one of the first or second resistances, or the third electric resistance.
    Type: Grant
    Filed: March 14, 2003
    Date of Patent: August 17, 2004
    Assignee: Renesas Technology Corp.
    Inventor: Jun Ohtani
  • Patent number: 6778445
    Abstract: Peripheral circuitry writes/reads input data and output data of L bits (L: integer of at least 2) that is input/output to/from a data node into/from first and second memory cell blocks that are selectively accessed. The peripheral circuitry uses circuit components operating in response to a clock signal to write/read the data by dividing the data writing operation/data reading operation into a plurality of stages and carrying out them in pipelining manner.
    Type: Grant
    Filed: January 30, 2003
    Date of Patent: August 17, 2004
    Assignees: Renesas Technology Corp., Mitsubishi Electric Engineering Company Limited
    Inventors: Tsukasa Ooishi, Hiroaki Tanizaki
  • Patent number: 6762952
    Abstract: Exemplar embodiments are disclosed which allow errors in a magnetoresistive solid-state storage device, such as a magnetic random access memory (MRAM) device, to be minimized. An illustrative method includes the steps of identifying cells in the device which have a failure mode characterized by a propensity to remain in a particular orientation of magnetization, mapping the location of the identified cells, and compensating for the failure mode of a cell at a mapped location. Systems and computer readable media are also provided.
    Type: Grant
    Filed: May 1, 2002
    Date of Patent: July 13, 2004
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Terrel R. Munden, Sarah M. Brandenberger
  • Patent number: 6757191
    Abstract: A tunneling magneto-resistance element of each MTJ (magnetic tunnel junction) memory cell is connected between a bit line and a strap. Each strap is shared by a plurality of tunneling magneto-resistance elements that are located adjacent to each other in the row direction in the same sub array. Each access transistor is connected between a corresponding strap and a ground voltage, and turned ON/OFF in response to a corresponding word line. Since data read operation can be conducted with the structure that does not have an access transistor for every tunneling magneto-resistance element, the array area can be reduced.
    Type: Grant
    Filed: August 19, 2002
    Date of Patent: June 29, 2004
    Assignee: Renesas Technology Corp.
    Inventors: Tsukasa Ooishi, Hideto Hidaka, Masatoshi Ishikawa
  • Patent number: 6750540
    Abstract: A magnetic random access memory (MRAM) using a Schottky diode is disclosed. In order to achieve high integration of the memory device, a word line is formed on a semiconductor substrate without using a connection layer and a stacked structure including an MTJ cell, a semiconductor layer and a bit line is formed on the word line, thereby forming the Schottky diode between the MTJ cell and the bit line. As a result, a structure of the device is simplified, and the device may be highly integrated due to repeated stacking.
    Type: Grant
    Filed: December 16, 2002
    Date of Patent: June 15, 2004
    Assignee: Hynix Semiconductor Inc.
    Inventor: Chang Shuk Kim
  • Patent number: 6714443
    Abstract: For writing K-bit write data in parallel (K is integer at least 2), bit lines each arranged for each memory cell columns and at least K current return lines are provided. K selected bit lines to write the K-bit write data are connected in series in a single current path. When data having different levels are written through adjacent selected bit lines, the selected bit lines are connected to each other at their one ends or the other ends, so that a bit line write current flowing through the former selected bit line is directly transmitted to the latter selected bit line. On the other hand, when data having the same level are written through adjacent selected bit lines, a bit line write current flowing through the former selected bit line is turned back by the corresponding current return line, and then transmitted to the latter selected bit line.
    Type: Grant
    Filed: June 14, 2002
    Date of Patent: March 30, 2004
    Assignee: Renesas Technology Corp.
    Inventor: Tsukasa Ooishi
  • Patent number: 6674663
    Abstract: A nonvolatile storage device and method of operation capable of preventing opens in a word line and/or bit line that may result from electromigration is disclosed. A nonvolatile storage device according to an embodiment may include a number of magnetic resistance elements provided at intersections of word lines and bit lines, a word line control circuit for selecting one word line and supplying a write current thereto in a write operation, and a bit line control circuit for selecting one bit line and supplying a write current thereto. A word line control circuit can provide a bidirectional write current to a word line.
    Type: Grant
    Filed: December 16, 2002
    Date of Patent: January 6, 2004
    Assignee: NEC Electronics Corporation
    Inventors: Takeshi Okazawa, Yuukoh Katoh
  • Patent number: 6667899
    Abstract: A magnetic memory (400) is programmed by selectively conducting current in opposite directions in both word and bit lines to reduce electromigration effects in word lines and bit lines. Various criteria, such as a data value being programmed and a previous current direction are used to determine the direction of the write currents used in the word and bit lines during programming.
    Type: Grant
    Filed: March 27, 2003
    Date of Patent: December 23, 2003
    Assignee: Motorola, Inc.
    Inventors: Chitra K. Subramanian, Thomas W. Andre, Joseph J. Nahas
  • Patent number: 6639823
    Abstract: A ferroelectric memory device includes a memory cell array in which a plurality of memory cells having at least one ferroelectric capacitor are arranged. Three or more values of data (Pr(0), P1(1), and −Pr(2), for example) can be selectively stored in the ferroelectric capacitor by applying voltages having three or more different values for setting three or more polarization states in the ferroelectric capacitor.
    Type: Grant
    Filed: December 27, 2001
    Date of Patent: October 28, 2003
    Assignee: Seiko Epson Corporation
    Inventor: Kazumasa Hasegawa
  • Patent number: 6625053
    Abstract: A memory cell array is constructed by a plurality of sub-arrays which include a plurality of sub-word lines, a plurality of bit lines, a plurality of plate lines and a plurality of memory cell blocks, plural ones of the sub-arrays being arranged in the sub-word line direction, a plurality of sub-row decoders provided between the plurality of respective sub-arrays, for driving the sub-word lines, a main row decoder disposed on one-end side of the plurality of sub-arrays in the sub-word line direction, and a plurality of main-block selecting lines for respectively supplying outputs of the main row decoder to the sub-row decoders. The main-block selecting lines for connecting the main row decoder to the sub-row decoders are formed of the same interconnection layer as the plate lines and metal interconnections used between the memory cells in the cell block.
    Type: Grant
    Filed: October 25, 2002
    Date of Patent: September 23, 2003
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Daisaburo Takashima
  • Patent number: 6618317
    Abstract: During data write, a first driver electrically connects a fist shared node to one of first and second voltages in accordance with write data. A second driver electrically connects a second shared node to the other voltage. A plurality of first switch circuits for electrically connecting one end sides of bit lines to the first shared node, respectively, and a plurality of second switch circuits for electrically connecting the other end sides to the second shared node, respectively, are provided. In accordance with a column select result, the first and second switch circuit for the corresponding bit line are turned on. Therefore, it is possible to execute a data write operation without providing a driver for each bit line.
    Type: Grant
    Filed: December 31, 2002
    Date of Patent: September 9, 2003
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Takaharu Tsuji, Tsukasa Ooishi
  • Patent number: 6541792
    Abstract: A memory device includes memory cells having two tunnel junctions in series. In order to program a selected memory cell, a first tunnel junction in the selected memory cell is blown. Blowing the first tunnel junction creates a short across the first tunnel junction, and changes the resistance of the selected memory cell from a first state to a second state. The change in resistance is detectable by a read process. The second tunnel junction has different anti-fuse characteristic than the first tunnel junction, and is not shorted by the write process. The second tunnel junction can therefore provide an isolation function to the memory cell after the first tunnel junction is blown.
    Type: Grant
    Filed: September 14, 2001
    Date of Patent: April 1, 2003
    Assignee: Hewlett-Packard Development Company, LLP
    Inventors: Lung T. Tran, Heon Lee
  • Patent number: 6418050
    Abstract: A memory device is described which has an n-channel field effect transistor coupled between a memory cell and a data communication line. An NPN bipolar junction transistor is also coupled between the memory cell and the data communication line in parallel to the n-channel access transistor. A base connection of the NPN bipolar junction transistor is described as coupled to a body of the n-channel access transistor. During operation the n-channel field effect transistor is used for writing data to a memory cell, while the NPN bipolar junction transistor is used for read operations in conjunction with a current sense amplifier circuit. The access transistors are described as fabricated as a single vertical pillar.
    Type: Grant
    Filed: July 27, 2001
    Date of Patent: July 9, 2002
    Assignee: Micron Technology, Inc.
    Inventor: Leonard Forbes
  • Patent number: 6349054
    Abstract: In the data read operation, a memory cell and a dummy memory cell are respectively coupled to two bit lines of a selected bit line pair, and a data read current is supplied thereto. In the selected memory cell column, a read gate drives the respective voltages on a read data bus pair, according to the respective voltages on the bit lines. A data read circuit amplifies the voltage difference between the read data buses so as to output read data. The use of the read gate enables the read data buses to be disconnected from a data read current path. As a result, respective voltage changes on the bit lines are rapidly produced, whereby the data read speed can be increased.
    Type: Grant
    Filed: May 10, 2001
    Date of Patent: February 19, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Hideto Hidaka
  • Patent number: 6317359
    Abstract: A device and method for sensing the status of a non-volatile magnetic latch. A cross-coupled inverter pair latch cell is employed for the data sensing. During the ‘Sense’ cycles, the inputs to the latch cell are from Giant Magneto-Resistive effect devices, each located in its respective inverter pair. The magneto-resistive storage devices have complimentary resistance states written into them. A switch, connected to the inverter pairs, is used to reset and initiate a regenerative sequence. Whenever the switch is turned on (reset) and off (regenerate), the latch cell will sense a potential imbalance generated by the magneto-resistive storage devices with complimentary resistance. During regeneration, the imbalance will be amplified and eventually the inverter pairs will reach a logic high or logic low state. The latch can be used as a memory circuit, however, upon loss of power the memory is retained. The state of the circuit is retained inside of GMR components.
    Type: Grant
    Filed: June 28, 2000
    Date of Patent: November 13, 2001
    Assignee: Iowa State University Research Foundation, Inc.
    Inventors: William C. Black, Marwan M. Hassoun