Patents by Inventor Ryu Ogiwara
Ryu Ogiwara 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: 20200302975Abstract: According to one embodiment, a nonvolatile memory device includes first and second word lines, first and second bit lines, memory cells each including a resistance change memory element, a global word line including a first global word line portion including a first end portion, a global bit line including a first global bit line portion including a second end portion. The first and second word lines and the first global bit line portion have a first line width and a first line thickness, the first and second bit lines and the first global word line portion have a second line width and a second line thickness.Type: ApplicationFiled: September 13, 2019Publication date: September 24, 2020Applicant: TOSHIBA MEMORY CORPORATIONInventors: Takahiko IIZUKA, Daisaburo TAKASHIMA, Ryu OGIWARA
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Patent number: 10672468Abstract: According to one embodiment, a memory device includes a first circuit including a resistance change memory element capable of setting a low resistance state or a high resistance state according to a falling speed of an applied voltage, and a first rectifier element connected in series to the resistance change memory element, and a second circuit including a current source, and a second rectifier element connected in series to the current source, the second circuit having a mirror relationship with the first circuit.Type: GrantFiled: March 14, 2019Date of Patent: June 2, 2020Assignee: TOSHIBA MEMORY CORPORATIONInventors: Ryu Ogiwara, Daisaburo Takashima
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Publication number: 20200098426Abstract: According to one embodiment, a memory device includes a memory cell including a resistance change memory element and a selector element, a word line, a bit line connected to one end of the memory cell, an operational amplifier including a non-inverting input connected to the bit line, an output circuit including a first terminal connected to an output of the operational amplifier, a second terminal connected to the bit line, and a charge/discharge circuit including a capacitor, a charge circuit and a discharge circuit, each including one end connected to an inverting input of the operational amplifier. At the time of falling of a write voltage for the memory cell, a potential of the other end of the memory cell is set higher than a potential of the other end of the discharge circuit.Type: ApplicationFiled: March 14, 2019Publication date: March 26, 2020Applicant: Toshiba Memory CorporationInventors: Ryu Ogiwara, Daisaburo Takashima, Takahiko Iizuka
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Patent number: 10490271Abstract: According to one embodiment, a resistance change memory device comprises a memory cell array in which a plurality of resistance change storage elements each to store one of multiple resistance states as data represented in two or more bits are arranged, and a read unit to read the data of a selected one of the storage elements. In reading the data of the storage element, the read unit, selecting one at a time, applies multiple types of constant voltages to the storage element.Type: GrantFiled: March 8, 2018Date of Patent: November 26, 2019Assignee: Toshiba Memory CorporationInventors: Ryu Ogiwara, Daisaburo Takashima
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Publication number: 20190295637Abstract: According to one embodiment, a memory device includes a first circuit including a resistance change memory element capable of setting a low resistance state or a high resistance state according to a falling speed of an applied voltage, and a first rectifier element connected in series to the resistance change memory element, and a second circuit including a current source, and a second rectifier element connected in series to the current source, the second circuit having a mirror relationship with the first circuit.Type: ApplicationFiled: March 14, 2019Publication date: September 26, 2019Applicant: Toshiba Memory CorporationInventors: Ryu Ogiwara, Daisaburo Takashima
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Patent number: 10410720Abstract: A semiconductor memory device includes a first conductor extending in a first direction and a second conductor extending in a second direction and disposed above the first conductor in a third direction. Third and fourth conductors extend in the first direction and adjacent to each other in the second direction. The third and fourth conductors are above the second conductor. A fifth conductor includes a variable resistance unit and is between the first and second conductors. A sixth conductor includes a variable resistance unit and is between the third and second conductors. A seventh conductor includes a variable resistance unit and is between the fourth and second conductors. A center point of the fifth conductor along a width of the fifth conductor is does not fully overlap with either of the sixth or seventh conductors along the third direction.Type: GrantFiled: September 4, 2017Date of Patent: September 10, 2019Assignee: TOSHIBA MEMORY CORPORATIONInventors: Takahiko Iizuka, Daisaburo Takashima, Ryu Ogiwara
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Publication number: 20190088319Abstract: According to one embodiment, a resistance change memory device comprises a memory cell array in which a plurality of resistance change storage elements each to store one of multiple resistance states as data represented in two or more bits are arranged, and a read unit to read the data of a selected one of the storage elements. In reading the data of the storage element, the read unit, selecting one at a time, applies multiple types of constant voltages to the storage element.Type: ApplicationFiled: March 8, 2018Publication date: March 21, 2019Applicant: Toshiba Memory CorporationInventors: Ryu OGIWARA, Daisaburo TAKASHIMA
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Publication number: 20180277202Abstract: A semiconductor memory device includes a first conductor extending in a first direction and a second conductor extending in a second direction and disposed above the first conductor in a third direction. Third and fourth conductors extend in the first direction and adjacent to each other in the second direction. The third and fourth conductors are above the second conductor. A fifth conductor includes a variable resistance unit and is between the first and second conductors. A sixth conductor includes a variable resistance unit and is between the third and second conductors. A seventh conductor includes a variable resistance unit and is between the fourth and second conductors. A center point of the fifth conductor along a width of the fifth conductor is does not fully overlap with either of the sixth or seventh conductors along the third direction.Type: ApplicationFiled: September 4, 2017Publication date: September 27, 2018Inventors: Takahiko IIZUKA, Daisaburo TAKASHIMA, Ryu OGIWARA
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Publication number: 20180268878Abstract: A variable resistance non-volatile semiconductor memory device comprises a memory cell having variable resistance element connected in series with a selection transistor. The selection transistor has a control terminal connected to a word line. A first end of the memory cell is connected to a bit line. A second end of the memory cell is connected to a first power supply line. An additional resistor is connected between a second power supply line and the bit line. The first power supply line is a low potential and the second power supply line is a high potential. During a reading operation of the memory cell, a read current flows through the first resistor and the memory cell.Type: ApplicationFiled: March 1, 2018Publication date: September 20, 2018Inventors: Ryu OGIWARA, Daisaburo TAKASHIMA
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Patent number: 10032509Abstract: According to one embodiment, a semiconductor memory device includes a memory cell including a variable resistance element, a first circuit including a first resistance element and a first transistor, a first bit line, a second transistor, and a sense circuit. The memory cell and the first circuit are connected to the first bit line. One end and the other end of the second transistor are connected to the first bit line and the sense circuit respectively. During a first operation before reading data of the memory cell a voltage of the first bit line falls to a first voltage and the first and second transistors are turned off in response to a fall of the voltage of the first bit line to the first voltage.Type: GrantFiled: March 9, 2016Date of Patent: July 24, 2018Assignee: TOSHIBA MEMORY CORPORATIONInventors: Ryu Ogiwara, Daisaburo Takashima
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Patent number: 9966136Abstract: According to one embodiment, a variable resistance memory includes first to third insulating layers, first and second variable resistance layers, first and second semiconductor layers, and first and second electric conductors. The first insulating layer extends in a first direction. The first and second electric conductors are in contact with the second and third insulating layers respectively. The first to third insulating layers, the first and second variable resistance layers and the first and second semiconductor layers are disposed between the first and second electric conductors in a second direction different from the first direction.Type: GrantFiled: February 27, 2017Date of Patent: May 8, 2018Assignee: TOSHIBA MEMORY CORPORATIONInventors: Ryu Ogiwara, Daisaburo Takashima
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Patent number: 9928903Abstract: According to one embodiment, a semiconductor storage device includes: a memory cell including a variable resistance element; a bit line coupled to the memory cell; and a first circuit applying a first voltage to the bit line in a write operation for the memory cell. When a temperature of the variable resistance element is lower than or equal to a first temperature, a temperature coefficient of the first voltage is 0. When the temperature of the variable resistance element is higher than the first temperature, the temperature coefficient of the first voltage is negative.Type: GrantFiled: August 26, 2016Date of Patent: March 27, 2018Assignee: Toshiba Memory CorporationInventors: Ryu Ogiwara, Daisaburo Takashima
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Publication number: 20180075903Abstract: According to one embodiment, a variable resistance memory includes first to third insulating layers, first and second variable resistance layers, first and second semiconductor layers, and first and second electric conductors. The first insulating layer extends in a first direction. The first and second electric conductors are in contact with the second and third insulating layers respectively. The first to third insulating layers, the first and second variable resistance layers and the first and second semiconductor layers are disposed between the first and second electric conductors in a second direction different from the first direction.Type: ApplicationFiled: February 27, 2017Publication date: March 15, 2018Applicant: TOSHIBA MEMORY CORPORATIONInventors: Ryu OGIWARA, Daisaburo TAKASHIMA
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Patent number: 9607693Abstract: A semiconductor storage device according to the present embodiments includes a first bit line and a first word line. A resistance-change memory element is connected to the first bit line and the first word line. A sense node is connected to the first bit line in a data read operation. A first transistor is connected between the sense node and the first bit line. A second transistor connects the first bit line and a power supply to each other in a data write operation. A first operational amplifier has one input connected to the first bit line, other input receiving a reference voltage, and an output connected in common to a gate of the first transistor and a gate of the second transistor. A sense circuit is connected to the sense node.Type: GrantFiled: October 12, 2015Date of Patent: March 28, 2017Assignee: KABUSHIKI KAISHA TOSHIBAInventors: Ryu Ogiwara, Daisaburo Takashima
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Publication number: 20160365143Abstract: According to one embodiment, a semiconductor storage device includes: a memory cell including a variable resistance element; a bit line coupled to the memory cell; and a first circuit applying a first voltage to the bit line in a write operation for the memory cell. When a temperature of the variable resistance element is lower than or equal to a first temperature, a temperature coefficient of the first voltage is 0. When the temperature of the variable resistance element is higher than the first temperature, the temperature coefficient of the first voltage is negative.Type: ApplicationFiled: August 26, 2016Publication date: December 15, 2016Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Ryu OGIWARA, Daisaburo TAKASHIMA
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Publication number: 20160293252Abstract: According to one embodiment, a semiconductor storage device includes: a first memory cell; a first bit line coupled to the first memory cell; and a first circuit applying a first voltage to the first bit line in a write operation for the first memory cell. The first voltage has no temperature dependence at temperatures lower than or equal to a first temperature, and has a negative temperature dependence at temperatures higher than the first temperature.Type: ApplicationFiled: September 8, 2015Publication date: October 6, 2016Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Ryu OGIWARA, Daisaburo TAKASHIMA
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Publication number: 20160293251Abstract: According to one embodiment, a semiconductor memory device includes: a plurality of memory cells, each of which including a memory element and a first switch element; the memory element storing data in accordance with a resistance values; a bit line connected to the memory cells; a charge transfer transistor that connects the bit line and a sense node; a sense circuit connected to the sense node; and a pulldown circuit connected to the bit line. The pulldown circuit causes a voltage of the bit line to drop to a first voltage obtained by subtracting a threshold voltage of the charge transfer transistor from a gate voltage of the charge transfer transistor before reading the data from the memory cell.Type: ApplicationFiled: September 4, 2015Publication date: October 6, 2016Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Ryu OGIWARA, Daisaburo TAKASHIMA
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Publication number: 20160293253Abstract: According to one embodiment, a semiconductor memory device includes a memory cell including a variable resistance element, a first circuit including a first resistance element and a first transistor, a first bit line, a second transistor, and a sense circuit. The memory cell and the first circuit are connected to the first bit line. One end and the other end of the second transistor are connected to the first bit line and the sense circuit respectively. During a first operation before reading data of the memory cell a voltage of the first bit line falls to a first voltage and the first and second transistors are turned off in response to a fall of the voltage of the first bit line to the first voltage.Type: ApplicationFiled: March 9, 2016Publication date: October 6, 2016Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Ryu OGIWARA, Daisaburo TAKASHIMA
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Patent number: 9460785Abstract: A semiconductor storage device according to the present embodiment includes a constant current source. A reference current path is connected to the constant current source to flow a reference current and to generate a reference voltage. A supply current path or a plurality of supply current paths are connected to bit lines to selectively flow supply a current or currents different from each other and generate a detection voltage. A sense amplifier is connected to the reference current path and the supply current paths to amplify a voltage difference between the reference voltage and the detection voltage.Type: GrantFiled: September 10, 2014Date of Patent: October 4, 2016Assignee: KABUSHIKI KAISHA TOSHIBAInventors: Ryu Ogiwara, Daisaburo Takashima
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Publication number: 20160267969Abstract: A semiconductor storage device according to the present embodiments includes a first bit line and a first word line. A resistance-change memory element is connected to the first bit line and the first word line. A sense node is connected to the first bit line in a data read operation. A first transistor is connected between the sense node and the first bit line. A second transistor connects the first bit line and a power supply to each other in a data write operation. A first operational amplifier has one input connected to the first bit line, other input receiving a reference voltage, and an output connected in common to a gate of the first transistor and a gate of the second transistor. A sense circuit is connected to the sense node.Type: ApplicationFiled: October 12, 2015Publication date: September 15, 2016Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Ryu OGIWARA, Daisaburo TAKASHIMA