Patents by Inventor Akiyoshi Seko
Akiyoshi Seko 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: 9589608Abstract: In a semiconductor memory device storing a resistance difference as information, a long time is taken so as to charge and/or discharge a selected cell by an equalizer circuit, which results in a difficulty of a high speed operation. A selection circuit puts, in a selected state, at least three bit lines which includes a selected bit line connected to a selected memory cell together with unselected bit lines adjacent to the selected bit line on both sides of the selected bit line. The selected and the unselected bit lines are coupled to sense amplifiers through an equalizer circuit. The equalizer circuit puts both the selected and the unselected bit lines into charging states and thereafter puts only the selected bit line into a discharging state to perform a sensing operation. On the other hand, the unselected bit lines are continuously kept at the charging states during the sensing operation. This makes it possible to perform the sensing operation at a high speed with a rare malfunction.Type: GrantFiled: March 24, 2010Date of Patent: March 7, 2017Assignee: Longitude Semiconductor S.A.R.L.Inventor: Akiyoshi Seko
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Patent number: 9042156Abstract: A semiconductor memory device includes a writing circuit and a reading circuit. The writing circuit executes a setting action for converting a resistance of a variable resistance element to a low resistance by applying current from one end side to the other end side of a memory cell via the variable resistance element, and a resetting action for converting the resistance to a high resistance by applying current from the other end side to the one end side via the variable resistance element. The reading circuit executes a first reading action for reading a resistance state of the variable resistance element by applying current from one end side to the other end side of the memory cell via the variable resistance element, and a second reading action for reading the resistance state by applying current from the other end side to the one end side via the variable resistance element.Type: GrantFiled: October 9, 2012Date of Patent: May 26, 2015Assignee: Sharp Kabushiki KaishaInventors: Mitsuru Nakura, Nobuyoshi Awaya, Kazuya Ishihara, Akiyoshi Seko
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Patent number: 8817525Abstract: A semiconductor memory device includes a memory cell array having a plurality of memory cells arranged in a matrix, each memory cell being configured such that a variable resistance element and a selection transistor are connected in series. A set operation for a memory cell (an operation of converting the resistance of the variable resistance element to a low resistance) is performed by applying a set voltage pulse for a longer time than that for a reset operation (an operation of converting the resistance of the variable resistance element to a high resistance) while limiting, using the selection transistor, an electric current flowing in the set operation to a certain low electric current, and by simultaneously applying the set voltage pulse to the plurality of memory cells.Type: GrantFiled: August 5, 2013Date of Patent: August 26, 2014Assignees: Sharp Kabushiki Kaisha, Elpida Memory, Inc.Inventors: Kazuya Ishihara, Yukio Tamai, Takashi Nakano, Akiyoshi Seko
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Patent number: 8787068Abstract: A semiconductor device includes first and second interconnects, a variable resistance element that may assume a first resistance value or a second resistance value in response to the current flowing therein, first and second transistors connected between the first and second interconnects in series with each other on both sides of the variable resistance element, and a power supply circuit unit that delivers the power supply to a control electrode of the first transistor. The power supply circuit unit supplies the power of a first power supply when the variable resistance element is to make transition to the first resistance value and the power supply circuit unit supplies the power of a second power supply when the variable resistance element is to make transition to the second resistance value, thereby allowing transitioning of the resistance values of the variable resistance element.Type: GrantFiled: April 5, 2012Date of Patent: July 22, 2014Assignee: Elpida Memory, Inc.Inventors: Akiyoshi Seko, Tatsuya Matano
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Publication number: 20140036573Abstract: A semiconductor memory device includes a memory cell array having a plurality of memory cells arranged in a matrix, each memory cell being configured such that a variable resistance element and a selection transistor are connected in series. A set operation for a memory cell (an operation of converting the resistance of the variable resistance element to a low resistance) is performed by applying a set voltage pulse for a longer time than that for a reset operation (an operation of converting the resistance of the variable resistance element to a high resistance) while limiting, using the selection transistor, an electric current flowing in the set operation to a certain low electric current, and by simultaneously applying the set voltage pulse to the plurality of memory cells.Type: ApplicationFiled: August 5, 2013Publication date: February 6, 2014Applicants: ELPIDA MEMORY, INC., SHARP KABUSHIKI KAISHAInventors: Kazuya ISHIHARA, Yukio TAMAI, Takashi NAKANO, Akiyoshi SEKO
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Patent number: 8510613Abstract: A method includes temporarily storing write-data to be written into non-volatile memory cells, respectively, the memory cells being divided into cell groups, performing a first operation including write-phases performed in series and on an associated cell group and including applying a write-voltage to the memory cells belonging to the associated cell group in response to an associated write-data to be written into the memory cells belonging to the cell groups, and performing a second operation after the first operation is completed, which includes read-phases performed in series and on an associated cell group and including applying a first read-voltage to the memory cell or cells belonging to the associated one of the cell groups to produce first read-data therefrom, and comparing the first read-data with the write-data to be written into the memory cells belonging to the associated cell groups to produce comparison data.Type: GrantFiled: February 25, 2011Date of Patent: August 13, 2013Assignee: Elpida Memory, Inc.Inventor: Akiyoshi Seko
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Publication number: 20120257437Abstract: A semiconductor device includes first and second interconnects, a variable resistance element that may assume a first resistance value or a second resistance value in response to the current flowing therein, and second transistors connected between the first and second interconnects in series with each other on both sides of the variable resistance element, and a power supply circuit unit that delivers the power supply to a control electrode of the first transistor.Type: ApplicationFiled: April 5, 2012Publication date: October 11, 2012Applicant: Elpida Memory, Inc.Inventors: Akiyoshi SEKO, Tatsuya Matano
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Patent number: 8129709Abstract: A nonvolatile memory device (21) is provided with a semiconductor substrate, a plurality of active regions (3) formed on the semiconductor substrate and extending in a band, a plurality of select active elements (23) formed in the active regions (3) and having a first impurity diffusion region and a second impurity diffusion region, a plurality of first electrodes (13) electrically connected to the first impurity diffusion region, a variable resistance layer (12) electrically connected to the first electrodes (13), and a plurality of second electrodes electrically connected to the variable resistance layer (12). Among the plurality of first electrodes (13) and the plurality of second electrodes, an array direction of at least one pair of the first electrodes (13) and the second electrodes that are electrically connected to the same variable resistance layer (12), and a direction of extension of the activation regions (3) are not parallel.Type: GrantFiled: November 13, 2009Date of Patent: March 6, 2012Assignee: Elpida Memory, Inc.Inventors: Akiyoshi Seko, Yukio Fuji, Natsuki Sato, Isamu Asano
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Publication number: 20110214025Abstract: Disclosed is a control method of a non-volatile semiconductor device including cells, wherein a stress for rewriting information is applied to each of the cells, and each cell has a first time period as a period of time until a characteristic of the cell is stabilized to expectation value information after the stress for rewriting information is applied, a plurality of first sequences, in each of which writing is performed to a plurality of the cells continuously in time series, and a plurality of second sequences, in each of which verification of a plurality of the cells is performed continuously in time series, after the writing performed continuous in time series.Type: ApplicationFiled: February 25, 2011Publication date: September 1, 2011Applicant: ELPIDA MEMORY, INC.Inventor: Akiyoshi Seko
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Patent number: 7985693Abstract: An area where a lower electrode is in contact with a variable resistance material needs to be reduced to lower the power consumption of a variable resistance memory device. The present invention is to provide a method of producing a variable resistance memory element whereby the lower electrode can be formed smaller. Combining an anisotropic etching process with an isotropic etching process enables the lower electrode to be formed smaller.Type: GrantFiled: October 17, 2008Date of Patent: July 26, 2011Assignee: Elpida Memory, Inc.Inventors: Akiyoshi Seko, Natsuki Sato, Isamu Asano
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Publication number: 20100246302Abstract: In a semiconductor memory device storing a resistance difference as information, a long time is taken so as to charge and/or discharge a selected cell by an equalizer circuit, which results in a difficulty of a high speed operation. A selection circuit puts, in a selected state, at least three bit lines which includes a selected bit line connected to a selected memory cell together with unselected bit lines adjacent to the selected bit line on both sides of the selected bit line. The selected and the unselected bit lines are coupled to sense amplifiers through an equalizer circuit. The equalizer circuit puts both the selected and the unselected bit lines into charging states and thereafter puts only the selected bit line into a discharging state to perform a sensing operation. On the other hand, the unselected bit lines are continuously kept at the charging states during the sensing operation. This makes it possible to perform the sensing operation at a high speed with a rare malfunction.Type: ApplicationFiled: March 24, 2010Publication date: September 30, 2010Applicant: ELPIDA MEMORY, INC.Inventor: Akiyoshi SEKO
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Publication number: 20100246241Abstract: A semiconductor device includes a plurality of word lines extending in a first direction, a plurality of bit lines extending in a second direction, a plurality of source lines formed along a third direction which is different from the first and the second directions, and a source line control circuit serving as a driving arrangement selectively driving the plurality of source lines.Type: ApplicationFiled: March 29, 2010Publication date: September 30, 2010Applicant: Elpida Memory, Inc.Inventors: Akiyoshi SEKO, Shuichi Tsukada
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Patent number: 7780001Abstract: A file wrapper for wrapping is provided. The file wrapper for wrapping comprises a file wrapper for wrapping comprising: a the cutting body, which comprises a unit piece of a covering paper and a backing paper of integral constitution that is bent to form a bag shape, sealing pieces provided to the covering paper and the backing paper, at the opening portion of the bag shape for inserting commodities, respectively, and side sticking pieces provided to the both sides portion of the covering paper. The one sealing piece is provided with a stopper of commodities after inserting them, and the other sealing piece is provided with the connecting piece inserted in the notch hole of the stopper and engaged thereto.Type: GrantFiled: July 26, 2005Date of Patent: August 24, 2010Assignee: Dainichi Printing Co., Ltd.Inventor: Akiyoshi Seko
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Publication number: 20100195415Abstract: A memory device is configured such that, in a read access: a first switch and a second switch are turned on in a pre-charge period before a memory cell is accessed so that charges of a bit line charge voltage generating circuit are distributed to a bit line and a reference bit line, to thereby charge the bit line and the reference bit line to an initial voltage. After the charge, a selected memory cell is connected to the bit line, the reference bit line is connected to a reference voltage generating circuit, and a voltage differential type sense amplifier amplifies a difference voltage between a voltage of the bit line decreased by discharge of the selected memory cell and a voltage of the reference bit line generated by the reference voltage generating circuit, to thereby read out memory cell data.Type: ApplicationFiled: February 1, 2010Publication date: August 5, 2010Applicant: ELPIDA MEMORY, INC.Inventor: Akiyoshi Seko
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Publication number: 20100123114Abstract: A nonvolatile memory device (21) is provided with a semiconductor substrate, a plurality of active regions (3) formed on the semiconductor substrate and extending in a band, a plurality of select active elements (23) formed in the active regions (3) and having a first impurity diffusion region and a second impurity diffusion region, a plurality of first electrodes (13) electrically connected to the first impurity diffusion region, a variable resistance layer (12) electrically connected to the first electrodes (13), and a plurality of second electrodes electrically connected to the variable resistance layer (12). Among the plurality of first electrodes (13) and the plurality of second electrodes, an array direction of at least one pair of the first electrodes (13) and the second electrodes that are electrically connected to the same variable resistance layer (12), and a direction of extension of the activation regions (3) are not parallel.Type: ApplicationFiled: November 13, 2009Publication date: May 20, 2010Inventors: Akiyoshi SEKO, Yukio FUJI, Natsuki SATO, Isamu ASANO
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Publication number: 20100078616Abstract: A nonvolatile memory device has a first insulating layer, a variable resistance layer provided on the first insulating layer and having a variable resistance material, and a first electrode and second electrode electrically connected with the variable resistance layer. The variable resistance layer has a variable resistance region as a data storing region and a thickness-changing region continuously extending from the variable resistance region and gradually becoming thicker from the variable resistance region.Type: ApplicationFiled: September 29, 2009Publication date: April 1, 2010Applicant: Elpida Memory, Inc.Inventors: Akiyoshi Seko, Natsuki Sato, Isamu Asano
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Publication number: 20090221146Abstract: The object of the present invention is to provide a manufacturing method for a nonvolatile memory device including a variable resistance having a constricted shape. The nonvolatile memory device of the present invention has a storage section composed of two electrodes and a variable resistance sandwiched between the electrodes. The variable resistance is formed to a constricted shape between the electrodes.Type: ApplicationFiled: February 27, 2009Publication date: September 3, 2009Applicant: Elpida Memory, Inc.Inventors: Akiyoshi Seko, Natsuki Sato, Isamu Asano
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Publication number: 20090104779Abstract: An area where a lower electrode is in contact with a variable resistance material needs to be reduced to lower the power consumption of a variable resistance memory device. The present invention is to provide a method of producing a variable resistance memory element whereby the lower electrode can be formed smaller. Combining an anisotropic etching process with an isotropic etching process enables the lower electrode to be formed smaller.Type: ApplicationFiled: October 17, 2008Publication date: April 23, 2009Inventors: Akiyoshi Seko, Natsuki Sato, Isamu Asano
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Publication number: 20090101885Abstract: An area where a lower electrode is in contact with a variable resistance material needs to be reduced in order to lower the power consumption of a variable resistance memory device. The present invention provides a method of producing a variable resistance memory element whereby the lower electrode can be more finely formed. The method of producing a semiconductor device according to the present invention includes forming a small opening by utilizing cubical expansion due to the oxidation of silicon. Thereby forming the lower electrode smaller than that can be formed by lithography techniques.Type: ApplicationFiled: October 10, 2008Publication date: April 23, 2009Inventors: Akiyoshi Seko, Natsuki Sato, Isamu Asano
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Publication number: 20060108404Abstract: A file wrapper for wrapping is provided. The file wrapper for wrapping comprises a file wrapper for wrapping comprising: a die cutting body, which comprises a unit piece of a covering paper and a backing paper of integral constitution that is bent to form a bag shape, sealing pieces provided to the covering paper and the backing paper, at the opening portion of the bag shape for inserting commodities, respectively, and side sticking pieces provided to the both sides portion of the covering paper. The one sealing piece is provided with a stopper of commodities after inserting them, and the other sealing piece is provided with the connecting piece inserted in the notch hole of the stopper and engaged thereto.Type: ApplicationFiled: July 26, 2005Publication date: May 25, 2006Inventor: Akiyoshi Seko