Patents by Inventor Noboru Sakimura
Noboru Sakimura has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20130181739Abstract: A semiconductor device comprises: reconfigurable logic circuit that includes plurality of resistance change elements; logical configuration of the reconfigurable logic circuit being decided depending on whether each of plurality of resistance change elements is in first resistance state or in second resistance state whose resistance value is lower than resistance value of first resistance state; resistance value monitor circuit that includes resistance change element pre-programmed to the first resistance state; the resistance value monitor circuit detecting whether or not pre-programmed resistance change element retains the first resistance state; and controller that, in case it is detected that resistance change element provided in resistance value monitor circuit doe not retain first resistance state, applies voltage used in programming from second resistance state to first resistance state to resistance change element retaining first resistance states, out of plurality of resistance change elements providType: ApplicationFiled: September 21, 2011Publication date: July 18, 2013Inventors: Noboru Sakimura, Munehiro Tada, Toshitsugu Sakamoto, Ryusuke Nebashi
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Patent number: 8477528Abstract: 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: GrantFiled: September 25, 2007Date of Patent: July 2, 2013Assignee: NEC CorporationInventors: Takeshi Honda, Noboru Sakimura, Tadahiko Sugibayashi, Hideaki Numata, Norikazu Ohshima
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Patent number: 8354861Abstract: A logic gate has a magnetoresistive element, a magnetization state control unit and an output unit. The magnetoresistive element has a laminated structure having N (N is an integer not smaller than 3) magnetic layers and N?1 nonmagnetic layers that are alternately laminated. A resistance value of the magnetoresistive element varies depending on magnetization states of the N magnetic layers. The magnetization state control unit sets the respective magnetization states of the N magnetic layers depending on N input data. The output unit outputs output data that varies depending on the resistance value of the magnetoresistive element.Type: GrantFiled: August 12, 2009Date of Patent: January 15, 2013Assignee: NEC CorporationInventors: Tadahiko Sugibayashi, Noboru Sakimura, Ryusuke Nebashi
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Patent number: 8299830Abstract: A semiconductor device having a nonvolatile variable resistor, includes: a resistance value conversion circuit unit configured to convert a resistance value of the nonvolatile variable resistor into a potential or a current and which outputs the converted potential or current; a comparison circuit unit configured to compare the output from the resistance value conversion circuit unit and a potential or current at a node of a portion within the semiconductor device; and a resistance value changing circuit unit configured to change the resistance value of the nonvolatile variable resistor based on the comparison results from the comparison circuit unit.Type: GrantFiled: January 18, 2008Date of Patent: October 30, 2012Assignee: NEC CorporationInventors: Tadahiko Sugibayashi, Noboru Sakimura
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Patent number: 8284595Abstract: A MRAM includes: first and second bit lines provided to extend in a first direction; a storage block including at least one magnetroresistive element for storing data; and a reading circuit. The reading circuit includes a first terminal electrically connected to the first bit line, and a second terminal electrically connected to the second bit line. The second terminal has a high impedance preventing a steady-state current from flowing into at a time of a reading operation. The reading circuit supplies a reading current from the first terminal to the first bit line at the time of the reading operation. The storage block is configured such that the reading current flows from the first bit line to the magnetroresistive element and the magnetroresistive element is connected to the second bit line at the time of the reading operation. The reading circuit controls the reading current on the basis of a voltage applied to the second terminal through the second bit line.Type: GrantFiled: October 30, 2008Date of Patent: October 9, 2012Assignee: NEC CorporationInventors: Ryusuke Nebashi, Noboru Sakimura, Tadahiko Sugibayashi
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Patent number: 8281221Abstract: An operation method of a MRAM of the present invention stores in memory arrays, error correction codes, each of which comprises of symbols, each of which comprises bits, and to which an error correction is possible in units of symbols. In the operation method, the symbols are read by using the reference cells different from each other. Moreover, when a correctable error is detected in a read data of the error correction code from data cells corresponding to an input address, (A) a data in the data cell corresponding to an error bit is corrected, for a first error symbol as an error pattern of one bit, and (B) a data in the reference cell that is used to read a second error symbol is corrected for a second error symbol as en error pattern of the bits.Type: GrantFiled: October 17, 2006Date of Patent: October 2, 2012Assignee: NEC CorporationInventors: Noboru Sakimura, Takeshi Honda, Tadahiko Sugibayashi
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Publication number: 20120206959Abstract: 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: ApplicationFiled: March 29, 2012Publication date: August 16, 2012Inventors: TAKESHI HONDA, NOBORU SAKIMURA, TADAHIKO SUGIBAYASHI, HIDEAKI NUMATA, NORIKAZU OHSHIMA
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Patent number: 8243502Abstract: A nonvolatile latch circuit includes: a latch circuit; a first magnetoresistance element and a second magnetoresistance element; and a current supply portion. The latch circuit temporarily holds data. Each of the first magnetoresistance element and the second magnetoresistance element includes a first magnetic layer and a second magnetic layer that are stacked with an insulating film sandwiched therebetween. The current supply portion complementarily changes magnetization states of the first magnetoresistance element and the second magnetoresistance element based on a state of the latch circuit. The first magnetic layer of the first magnetoresistance element and the first magnetic layer of the second magnetoresistance element are series-connected to each other in. The latch circuit has a function that brings data corresponding to the magnetization states to data held by the latch circuit.Type: GrantFiled: November 19, 2008Date of Patent: August 14, 2012Assignee: NEC CorporationInventors: Noboru Sakimura, Tadahiko Sugibayashi, Ryusuke Nebashi
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Patent number: 8174872Abstract: A nonvolatile latch circuit includes: first and second inverters cross-coupled to hold 1-bit data; first and second magnetoresistive elements each having first to third terminals; and a current supply circuitry configured to supply a magnetization reversal current for changing the magnetization states of the first and second maqnetoresistive elements in response to the 1-bit data. The power terminal of the first inverter is connected to the first terminal of the first magnetoresistive element and the power terminal of the second inverter is connected to the first terminal of the second magnetoresistive element. The current supply circuitry is configured to supply the magnetization reversal current to the second terminals of the first and second magnetoresistive elements. The third terminal of the first magnetoresistive element is electrically connected to the third terminal of the second magnetoresistive element.Type: GrantFiled: December 3, 2008Date of Patent: May 8, 2012Assignee: NEC CorporationInventors: Noboru Sakimura, Tadahiko Sugibayashi, Ryusuke Nebashi
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Publication number: 20120063199Abstract: A semiconductor device having a nonvolatile variable resistor, includes: a resistance value conversion circuit unit configured to convert a resistance value of the nonvolatile variable resistor into a potential or a current and which outputs the converted potential or current; a comparison circuit unit configured to compare the output from the resistance value conversion circuit unit and a potential or current at a node of a portion within the semiconductor device; and a resistance value changing circuit unit configured to change the resistance value of the nonvolatile variable resistor based on the comparison results from the comparison circuit unit.Type: ApplicationFiled: November 21, 2011Publication date: March 15, 2012Inventors: Tadahiko SUGIBAYASHI, Noboru SAKIMURA
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Patent number: 8009467Abstract: An MRAM according to the present invention has: a memory cell array; a first word line and a second word line each connected to a group of memory cells arranged in a first direction; a plurality of blocks arranged in a matrix form; a common word line connected to a group of blocks arranged in the first direction; and a bit line pair connected to a group of blocks arranged in a second direction. Each block has a plurality of memory cells, and each memory cell has a first transistor and a magnetoresistance element. Each block further has a second transistor to which the plurality of memory cells are connected in parallel. A gate of the second transistor is connected to the common word line. A gate of the first transistor is connected to the first word line. One of source/drain of the first transistor is connected to the first bit line, and the other thereof is connected to one end of the magnetoresistance element and connected to the second bit line through the second transistor.Type: GrantFiled: April 22, 2008Date of Patent: August 30, 2011Assignee: NEC CorporationInventors: Ryusuke Nebashi, Noboru Sakimura, Tadahiko Sugibayashi
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Patent number: 8009466Abstract: A semiconductor storage device is provided with a memory array including a plurality of memory cells. The plurality of memory cells includes: first and third memory cells arranged along one of an even-numbered row and an odd-numbered row, and a second memory cell arranged along the other. Each of the plurality of memory cells includes: a first transistor comprising first and second diffusion layers; a second transistor comprising third and fourth diffusion layers; and a magnetoresistance element having one of terminals thereof connected to an interconnection layer which provides an electrical connection between the second and third diffusion layers. The fourth diffusion layer of the first memory cell is also used as the first diffusion layer of the second memory cell. In addition, the fourth diffusion layer of the second memory cell is also used as the first diffusion layer of the third memory cell.Type: GrantFiled: February 7, 2008Date of Patent: August 30, 2011Assignee: NEC CorporationInventors: Noboru Sakimura, Takeshi Honda, Tadahiko Sugibayashi
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Publication number: 20110148458Abstract: A logic gate 40 according to the present invention has a magnetoresistive element 1, a magnetization state control unit 50 and an output unit 60. The magnetoresistive element 1 has a laminated structure having N (N is an integer not smaller than 3) magnetic layers 10 and N?1 nonmagnetic layers that are alternately laminated. A resistance value R of the magnetoresistive element 1 varies depending on magnetization states of the N magnetic layers 10. The magnetization state control unit 50 sets the respective magnetization states of the N magnetic layers 10 depending on N input data. The output unit 60 outputs an output data that varies depending on the resistance value R of the magnetoresistive element 1.Type: ApplicationFiled: August 12, 2009Publication date: June 23, 2011Inventors: Tadahiko Sugibayashi, Noboru Sakimura, Ryusuke Nebashi
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Patent number: 7948783Abstract: An MRAM comprises: a plurality of magnetic memory cells each having a magnetoresistive element; and a magnetic field application section. The magnetic field application section applies an offset adjustment magnetic field in a certain direction to the plurality of magnetic memory cells from outside the plurality of magnetic memory cells. Respective data stored in the plurality of magnetic memory cells become the same when the offset adjustment magnetic field is removed.Type: GrantFiled: November 12, 2007Date of Patent: May 24, 2011Assignee: NEC CorporationInventors: Tadahiko Sugibayashi, Takeshi Honda, Noboru Sakimura, Nobuyuki Ishiwata, Shuichi Tahara
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Patent number: 7916520Abstract: A memory cell is used which includes a plurality of magneto-resistive elements and a plurality of laminated ferrimagnetic structure substances. The plurality of the magneto-resistive elements are placed corresponding to respective positions where a plurality of first wirings extended in a first direction intersects with a plurality of second wirings extended in a second direction which is substantially perpendicular to the first direction. The plurality of the laminated ferrimagnetic structure substances corresponds to the plurality of the magneto-resistive elements, respectively, is placed to have a distance of a predetermined range from the respective plurality of the magneto-resistive elements, and has a laminated ferrimagnetic structure. The magneto-resistive element includes a free layer having a laminated ferrimagnetic structure, a fixed layer, and a nonmagnetic layer interposed between the free layer and the fixed layer.Type: GrantFiled: August 19, 2005Date of Patent: March 29, 2011Assignee: NEC CorporationInventors: Tadahiko Sugibayashi, Takeshi Honda, Noboru Sakimura, Tetsuhiro Suzuki
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Patent number: 7885095Abstract: A magnetic random access memory of the present invention includes: a plurality of first wirings and a plurality of second wirings extending in a first direction; a plurality of third wirings and a plurality of fourth wirings extending in a second direction; and a plurality of memory cells provided at intersections of the plurality of first wirings and the plurality of third wirings, respectively. Each of the plurality of memory cells includes: a first transistor and a second transistor connected in series between one of the plurality of first wirings and one of the plurality of second wirings and controlled in response to a signal on one of the plurality of third wirings, a first magnetic resistance element having one end connected to a write wiring through which the first transistor and the second transistor are connected, and the other end grounded; and a second magnetic resistance element having one end connected to the write wiring, and the other end connected to the fourth wiring.Type: GrantFiled: June 1, 2007Date of Patent: February 8, 2011Assignee: NEC CorporationInventors: Noboru Sakimura, Takeshi Honda, Tadahiko Sugibayashi
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Patent number: 7885131Abstract: A semiconductor memory device of the present invention comprises a memory array and a read circuit that reads data of a selected cell. The memory array includes a plurality of memory cells and a reference cell each having a memory element that stores data based on change in resistance value. The read circuit includes: a voltage comparison unit that compares a value corresponding to a sense current from the selected cell with a value corresponding to a reference current from the reference cell; a first switch; and a second switch. Both of the first and second switches are provided at a subsequent stage of a decoder and at a preceding stage of the voltage comparison unit. The second switch circuit controls input of the value corresponding to the sense current to the voltage comparison unit, while the first switch circuit controls input of the value corresponding to the reference current to the voltage comparison unit.Type: GrantFiled: February 1, 2006Date of Patent: February 8, 2011Assignee: NEC CorporationInventors: Noboru Sakimura, Takeshi Honda, Tadahiko Sugibayashi
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Publication number: 20110016371Abstract: Provided is an operation method which can be applied to a PRAM, an ReRAM, and a solid electrolyte memory which stores error correction codes, each of which comprises of symbols, each of which comprises bits, and which codes allow error correction in units of symbols. In the operation method, the respective symbols are read by using different reference cells 12. When a correctable error is detected in read data from data cells forming the error correction codes and corresponding to an input address, a data in a data cell corresponding to the error bit is corrected for a first error symbol of an one bit error pattern, and data in a reference cell that is used to read the second error symbol are corrected for a second error symbol related to a multi-bit error pattern.Type: ApplicationFiled: April 14, 2008Publication date: January 20, 2011Inventors: Noboru Sakimura, Tadahiko Sugibayashi, Ryusuke Nebashi
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Publication number: 20100271866Abstract: A nonvolatile latch circuit includes: first and second inverters cross-coupled to hold 1-bit data; first and second magnetoresistive elements each having first to third terminals; and a current supply circuitry configured to supply a magnetization reversal current for changing the magnetization states of the first and second maqnetoresistive elements in response to the 1-bit data. The power terminal of the first inverter is connected to the first terminal of the first magnetoresistive element and the power terminal of the second inverter is connected to the first terminal of the second magnetoresistive element. The current supply circuitry is configured to supply the magnetization reversal current to the second terminals of the first and second magnetoresistive elements. The third terminal of the first magnetoresistive element is electrically connected to the third terminal of the second magnetoresistive element.Type: ApplicationFiled: December 3, 2008Publication date: October 28, 2010Inventors: Noboru Sakimura, Tadahiko Sugibayashi, Ryusuke Nebashi
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Publication number: 20100265760Abstract: A nonvolatile latch circuit includes: a latch circuit; a first magnetoresistance element and a second magnetoresistance element; and a current supply portion. The latch circuit temporarily holds data. Each of the first magnetoresistance element and the second magnetoresistance element includes a first magnetic layer and a second magnetic layer that are stacked with an insulating film sandwiched therebetween. The current supply portion complementarily changes magnetization states of the first magnetoresistance element and the second magnetoresistance element based on a state of the latch circuit. The first magnetic layer of the first magnetoresistance element and the first magnetic layer of the second magnetoresistance element are series-connected to each other in. The latch circuit has a function that brings data corresponding to the magnetization states to data held by the latch circuit.Type: ApplicationFiled: November 19, 2008Publication date: October 21, 2010Inventors: Noboru Sakimura, Tadahiko Sugibayashi, Ryusuke Nebashi