Patents by Inventor Tadahiko Sugibayashi
Tadahiko Sugibayashi 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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Patent number: 8693238Abstract: 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: GrantFiled: July 13, 2007Date of Patent: April 8, 2014Assignee: NEC CorporationInventors: Noboru Sakimura, Takeshi Honda, Tadahiko Sugibayashi
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Patent number: 8510633Abstract: 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: GrantFiled: April 14, 2008Date of Patent: August 13, 2013Assignee: NEC CorporationInventors: Noboru Sakimura, Tadahiko Sugibayashi, Ryusuke Nebashi
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Patent number: 8503222Abstract: A non-volatile logic circuit includes an input section, a control section and an output section. The input section has perpendicular magnetic anisotropy and has a ferromagnetic layer whose magnetization state is changeable. The control section includes a ferromagnetic layer. The output section is provided in a neighborhood of the input section and the control section and includes a magnetic tunnel junction element whose magnetization state is changeable. The magnetization state of the input section is changed based on the magnetization state. A magnetization state of the magnetic tunnel junction element of the output section which state is changed based on the magnetization state of the ferromagnetic material of the control section and the magnetization state of the ferromagnetic material of the input section.Type: GrantFiled: January 21, 2010Date of Patent: August 6, 2013Assignee: NEC CorporationInventors: Tetsuhiro Suzuki, Shunsuke Fukami, Kiyokazu Nagahara, Nobuyuki Ishiwata, Tadahiko Sugibayashi, Noboru Sakimura, Ryusuke Nebashi
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Publication number: 20130182501Abstract: A magnetoresistive element 10 having a memory cell 100 according to the present invention contains a first lower terminal n1 and a second lower terminal n2 respectively connected to both ends of a conductive layer 3 whose longitudinal direction is different from the column direction (X direction). Further, the gates of the first transistors M1 respectively included in two memory cells among the plurality of memory cells 100 and adjacent to each other in a row direction (Y direction) are commonly connected to a first word line 14. As a result, without increase of the cell area, it becomes possible to reserve a margin in the dimension of the cell structure or in the process for MRMA.Type: ApplicationFiled: December 6, 2011Publication date: July 18, 2013Inventors: Noboru Sakimura, Ryusuke Nebashi, Tadahiko Sugibayashi
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Publication number: 20130175645Abstract: A magnetoresistive effect element of the present invention includes: a domain wall motion layer, a spacer layer and a reference layer. The domain wall motion layer is made of ferromagnetic material with perpendicular magnetic anisotropy. The spacer layer is formed on the domain wall motion layer and made of non-magnetic material. The reference layer is formed on the spacer layer and made of ferromagnetic material, magnetization of the reference layer being fixed. The domain wall motion layer includes at least one domain wall, and stores data corresponding to a position of the domain wall. An anisotropy magnetic field of the domain wall motion layer is larger than a value in which the domain wall motion layer can hold the perpendicular magnetic anisotropy, and smaller than an essential value of an anisotropy magnetic field of the ferromagnetic material of the domain wall motion layer.Type: ApplicationFiled: December 14, 2010Publication date: July 11, 2013Applicant: NEC CORPORATIONInventors: Tadahiko Sugibayashi, Eiji Kariyada, Kaoru Mori, Norikazu Ohshima, Shunsuke Fukami, Tetsuhiro Suzuki, Hironobu Tanigawa, Sadahiko Miura, Nobuyuki Ishiwata
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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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Patent number: 8254157Abstract: A semiconductor integrated circuit includes: an oxide resistance change element, a constant current source circuit supplying a write current to the oxide resistance change element, and a voltage clamper clamping a voltage in a path in which a write current flows. The voltage clamper is arranged in parallel with the path between the constant current source circuit and the oxide resistance change element.Type: GrantFiled: January 17, 2008Date of Patent: August 28, 2012Assignee: NEC CorporationInventor: 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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Publication number: 20110292718Abstract: A non-volatile logic circuit includes an input section, a control section and an output section. The input section has perpendicular magnetic anisotropy and has a ferromagnetic layer whose magnetization state is changeable. The control section includes a ferromagnetic layer. The output section is provided in a neighborhood of the input section and the control section and includes a magnetic tunnel junction element whose magnetization state is changeable. The magnetization state of the input section is changed based on the magnetization state. A magnetization state of the magnetic tunnel junction element of the output section which state is changed based on the magnetization state of the ferromagnetic material of the control section and the magnetization state of the ferromagnetic material of the input section.Type: ApplicationFiled: January 21, 2010Publication date: December 1, 2011Inventors: Tetsuhiro Suzuki, Shunsuke Fukami, Kiyokazu Nagahara, Nobuyuki Ishiwata, Tadahiko Sugibayashi, Noburu Sakimura, Ryusuke Nebashi
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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