Patents by Inventor Daisaburo Takashima
Daisaburo Takashima 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: 12207480Abstract: A variable resistance non-volatile memory includes a semiconductor substrate, a first electrode line extending in a first direction away from the semiconductor substrate, a second electrode line extending in the first direction parallel to the first electrode line, an insulating film between the first and second electrode lines, a variable resistance film formed on the first electrode line, a low electrical resistance layer formed on the variable resistance film and having a lower electrical resistance than the variable resistance film, a semiconductor film in contact with the low electrical resistance layer and the insulating film, and formed on opposite surfaces of the second electrode line, a gate insulator film extending in the first direction and in contact with the semiconductor film, and a voltage application electrode that extends in a second direction that crosses the first direction, and is in contact with the gate insulator film.Type: GrantFiled: August 31, 2022Date of Patent: January 21, 2025Assignee: Kioxia CorporationInventors: Tomoki Chiba, Daisaburo Takashima, Hidehiro Shiga
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Patent number: 12144189Abstract: According to a certain embodiment, the 3D stacked semiconductor memory includes: a first electrode line extending in a first direction orthogonal to the semiconductor substrate; a second electrode line adjacent to the first electrode line in a second direction orthogonal to the first direction, and extending in the first direction; a first variable resistance film extending in the first direction and in contact with the second electrode line; a first semiconductor film in contact with the first variable resistance film and the first electrode line; a first potential applying electrode extending in the second direction and in contact with a first insulator layer; a second semiconductor film in contact with a second variable resistance film and the first electrode line; and a second potential applying electrode extending in the second direction and in contact with a second insulator layer. The first and second potential applying electrodes are electrically different nodes.Type: GrantFiled: September 7, 2022Date of Patent: November 12, 2024Assignee: Kioxia CorporationInventors: Hidehiro Shiga, Daisaburo Takashima
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Publication number: 20240321352Abstract: According to one embodiment, a device includes: a memory cell coupled to a bit line and configured to store first data including first, second, and third bits; and a sense amplification circuit configured to perform a first comparison between a bit line voltage and a first reference voltage, and a second comparison between the bit line voltage and a second reference voltage lower than the first reference voltage, and to read the first data from the memory cell based on results of the first and second comparisons. The sense amplification circuit is configured to retain second data having a first code in response to the bit line voltage becoming equal to or lower than the first reference voltage during a first period from a start of operation to a first time point, and retain the first data after the first period.Type: ApplicationFiled: March 13, 2024Publication date: September 26, 2024Applicant: Kioxia CorporationInventors: Ryu OGIWARA, Hidehiro SHIGA, Daisaburo TAKASHIMA
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Publication number: 20240315052Abstract: A semiconductor storage device includes a stacked body having a plurality of conductive layers stacked in a stacking direction with an insulating layer interposed therebetween, and a columnar structure that extends in the stacking direction in the stacked body. The columnar structure has a variable-resistance film, a semiconductor film, an insulating film, and a resistor film, all of which extend in the stacking direction in the stacked body. The semiconductor film is between the variable-resistance film and the conductive layer. The insulating film is between the semiconductor film and the conductive layer. The resistor film is between the variable-resistance film and the semiconductor film. Memory cells are formed at locations where the conductive layers, the variable-resistance film, and the semiconductor film intersect. In each of the memory cells, the thickness of the resistor film is greater than the thickness of the variable-resistance film.Type: ApplicationFiled: March 4, 2024Publication date: September 19, 2024Inventor: Daisaburo TAKASHIMA
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Patent number: 12069872Abstract: A memory device includes: a first interconnect; a second interconnect; a first string and a second string whose first ends are coupled to the first interconnect; a third string and a fourth string whose second ends are coupled to the second interconnect; a third interconnect; and driver. The third interconnect is coupled to second ends of the first and second strings and to first ends of the third and fourth strings. Each of the first, second, third, and fourth strings includes a first switch element and a memory cell coupled in series. The memory cell includes a second switch element and a resistance change element coupled in parallel. The third interconnect is coupled to the driver via the first interconnect or the second interconnect.Type: GrantFiled: August 8, 2023Date of Patent: August 20, 2024Assignee: Kioxia CorporationInventors: Takahiko Iizuka, Daisaburo Takashima, Ryu Ogiwara, Rieko Funatsuki, Yoshiki Kamata, Misako Morota, Yoshiaki Asao, Yukihiro Nomura
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Patent number: 11972798Abstract: A nonvolatile memory includes a first memory cell and a second memory cell above the first memory cell. The first memory cell includes a variable resistance layer extending in a first direction, a semiconductor layer extending in the first direction and in contact with the variable resistance layer, an insulator layer extending in the first direction and in contact with the semiconductor layer, and a first voltage applying electrode extending in a second direction and in contact with the insulator layer. The second memory cell includes a second voltage applying electrode in contact with the insulator layer. When a write operation is performed on the first memory cell, a first voltage is applied to the second voltage applying electrode, and when a write operation is performed on the second memory cell, a second voltage, lower than the first voltage, is applied to the first voltage applying electrode.Type: GrantFiled: February 25, 2022Date of Patent: April 30, 2024Assignee: Kioxia CorporationInventors: Tomoki Chiba, Daisaburo Takashima, Hidehiro Shiga
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Patent number: 11972797Abstract: A memory device includes a memory cell array including a select transistor and a plurality of memory cells connected in series, each memory cell including a cell transistor and a variable resistance layer connected in parallel. During a write operation, a voltage setting circuit is controlled to apply a first voltage to a selected word line and a second voltage to non-selected word lines. The time period for applying the first voltage to the selected word line starts later than the time period for applying the second voltage to the non-selected word lines and ends earlier than the time period for applying the second voltage to the non-selected word lines.Type: GrantFiled: February 24, 2022Date of Patent: April 30, 2024Assignee: Kioxia CorporationInventors: Hidehiro Shiga, Daisaburo Takashima
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Patent number: 11948636Abstract: According to one embodiment, a memory device includes a stacked structure including a plurality of conductive layers stacked to be apart from each other in a first direction, and a pillar structure including a resistance change portion extending in the first direction in the stacked structure, and a semiconductor portion which extends in the first direction in the stacked structure and which includes a first portion provided along the resistance change portion and a second portion extending from the first portion in at least one direction intersecting the first direction.Type: GrantFiled: March 14, 2022Date of Patent: April 2, 2024Assignee: Kioxia CorporationInventors: Yoshiki Kamata, Yoshiaki Asao, Yukihiro Nomura, Misako Morota, Daisaburo Takashima, Takahiko Iizuka, Shigeru Kawanaka
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Publication number: 20240099027Abstract: According to one embodiment, a cell block includes memory cells and select transistors. The memory cells correspond are connected in parallel between a local source line and a local bit line. The select transistor is connected between the local bit line and a bit line. The memory cell includes a cell transistor and a resistance change element. A gate of the cell transistor is connected to a word line. The resistance change element is connected to the cell transistor in series between the local source line and the local bit line. Each cell block is configured as a columnar structure penetrating a plurality of conductive films functioning as word lines. The select transistor and the local bit line are connected at a contact portion formed of a material different from a material of the local bit line.Type: ApplicationFiled: March 7, 2023Publication date: March 21, 2024Inventors: Kensuke TAKAHASHI, Daisaburo TAKASHIMA, Naoki KAI, Yasumi ISHIMOTO
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Publication number: 20240049479Abstract: A variable resistance non-volatile memory includes a memory cell including a core portion extending in a first direction above a semiconductor substrate, a variable resistance layer extending in a first direction and in contact with the core portion, a semiconductor layer extending in a first direction and in contact with the variable resistance layer, an insulator layer extending in a first direction and in contact with the semiconductor layer, and a first voltage application electrode extending in a second direction crossing the first direction and in contact with the insulator layer. An impurity concentration of the semiconductor layer is non-uniform, such that an impurity concentration of a first portion of the semiconductor layer in contact with the insulator layer is at least ten times higher than an impurity concentration of a second portion of the semiconductor layer in contact with the variable resistance layer.Type: ApplicationFiled: March 1, 2023Publication date: February 8, 2024Inventors: Yuki ITO, Daisaburo TAKASHIMA, Hidehiro SHIGA, Yoshiki KAMATA
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Publication number: 20240038279Abstract: According to one embodiment, in a semiconductor memory device, multiple first memory cells are connected in parallel between a first local bit line and a local source line. Multiple second memory cells are connected in parallel between a second local bit line and the local source line. Each of the multiple first memory cells includes a first cell transistor and a first resistance change element connected in series. Each of the multiple second memory cells includes a second cell transistor and a second resistance change element connected in series. A first selection gate line extends in a second direction across multiple cell blocks arranged in the second direction. A second selection gate line is placed on the opposite side of the first selection gate line with the local source line interposed therebetween. The second selection gate line extends in the second direction across multiple cell blocks arranged in the second direction.Type: ApplicationFiled: July 26, 2023Publication date: February 1, 2024Applicant: Kioxia CorporationInventors: Ryu OGIWARA, Hidehiro SHIGA, Daisaburo TAKASHIMA
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Publication number: 20230413584Abstract: A memory device includes: a first interconnect; a second interconnect; a first string and a second string whose first ends are coupled to the first interconnect; a third string and a fourth string whose second ends are coupled to the second interconnect; a third interconnect; and driver. The third interconnect is coupled to second ends of the first and second strings and to first ends of the third and fourth strings. Each of the first, second, third, and fourth strings includes a first switch element and a memory cell coupled in series. The memory cell includes a second switch element and a resistance change element coupled in parallel. The third interconnect is coupled to the driver via the first interconnect or the second interconnect.Type: ApplicationFiled: August 8, 2023Publication date: December 21, 2023Applicant: Kioxia CorporationInventors: Takahiko IIZUKA, Daisaburo TAKASHIMA, Ryu OGIWARA, Rieko FUNATSUKI, Yoshiki KAMATA, Misako MOROTA, Yoshiaki ASAO, Yukihiro NOMURA
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Patent number: 11765916Abstract: A memory device includes: a first interconnect; a second interconnect; a first string and a second string whose first ends are coupled to the first interconnect; a third string and a fourth string whose second ends are coupled to the second interconnect; a third interconnect; and driver. The third interconnect is coupled to second ends of the first and second strings and to first ends of the third and fourth strings. Each of the first, second, third, and fourth strings includes a first switch element and a memory cell coupled in series. The memory cell includes a second switch element and a resistance change element coupled in parallel. The third interconnect is coupled to the driver via the first interconnect or the second interconnect.Type: GrantFiled: June 16, 2021Date of Patent: September 19, 2023Assignee: Kioxia CorporationInventors: Takahiko Iizuka, Daisaburo Takashima, Ryu Ogiwara, Rieko Funatsuki, Yoshiki Kamata, Misako Morota, Yoshiaki Asao, Yukihiro Nomura
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Publication number: 20230284464Abstract: According to a certain embodiment, the 3D stacked semiconductor memory includes: a first electrode line extending in a first direction orthogonal to the semiconductor substrate; a second electrode line adjacent to the first electrode line in a second direction orthogonal to the first direction, and extending in the first direction; a first variable resistance film extending in the first direction and in contact with the second electrode line; a first semiconductor film in contact with the first variable resistance film and the first electrode line; a first potential applying electrode extending in the second direction and in contact with a first insulator layer; a second semiconductor film in contact with a second variable resistance film and the first electrode line; and a second potential applying electrode extending in the second direction and in contact with a second insulator layer. The first and second potential applying electrodes are electrically different nodes.Type: ApplicationFiled: September 7, 2022Publication date: September 7, 2023Applicant: Kioxia CorporationInventors: Hidehiro SHIGA, Daisaburo TAKASHIMA
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Publication number: 20230284460Abstract: A variable resistance non-volatile memory includes a semiconductor substrate, a first electrode line extending in a first direction away from the semiconductor substrate, a second electrode line extending in the first direction parallel to the first electrode line, an insulating film between the first and second electrode lines, a variable resistance film formed on the first electrode line, a low electrical resistance layer formed on the variable resistance film and having a lower electrical resistance than the variable resistance film, a semiconductor film in contact with the low electrical resistance layer and the insulating film, and formed on opposite surfaces of the second electrode line, a gate insulator film extending in the first direction and in contact with the semiconductor film, and a voltage application electrode that extends in a second direction that crosses the first direction, and is in contact with the gate insulator film.Type: ApplicationFiled: August 31, 2022Publication date: September 7, 2023Inventors: Tomoki CHIBA, Daisaburo TAKASHIMA, Hidehiro SHIGA
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Patent number: 11742019Abstract: According to one embodiment, there is provided a nonvolatile semiconductor memory device including a cell array. The cell array includes an array of a plurality of string blocks. Among the plurality of local string blocks, one local string block includes a block selection transistor and remaining local string blocks do not include a block selection transistor. A gate terminal of the block selection transistor of the one local string block is connected to a block selection line. Signals of two word lines connected to two adjacent string blocks in the bit line direction are common signals. Signals of two block selection lines connected to the two adjacent string blocks are independent of each other.Type: GrantFiled: September 10, 2021Date of Patent: August 29, 2023Assignee: Kioxia CorporationInventor: Daisaburo Takashima
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Patent number: 11744088Abstract: According to one embodiment, a memory device includes: a first variable resistance layer; first and second semiconductor layers being in contact with the first variable resistance layer; a first word line; a second word line being adjacent to the first word line; and a third word line being adjacent to the first and second word lines with the first semiconductor layer, the first variable resistance layer, and the second semiconductor layer interposed therebetween, and provided between the first word line and the second word line. In the first variable resistance layer, a first region including a shortest path connecting the first word line and the third word line functions as a first memory cell, and a second region including a shortest path connecting the third word line and the second word line functions as a second memory cell.Type: GrantFiled: October 6, 2021Date of Patent: August 29, 2023Assignee: Kioxia CorporationInventors: Ryu Ogiwara, Daisaburo Takashima, Takahiko Iizuka
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Patent number: 11721371Abstract: According to one embodiment, a memory device includes: a plurality of memory cells stacked in a first direction orthogonal to a substrate and each including a memory element having at least three resistance states and a selector coupled in parallel to the memory element; a bit line electrically coupled to the memory cells and extending in a second direction intersecting the first direction; and a sense amplifier configured to compare a voltage of the bit line with a plurality of reference voltages and sense data stored in the memory cells.Type: GrantFiled: October 6, 2021Date of Patent: August 8, 2023Assignee: Kioxia CorporationInventors: Ryu Ogiwara, Daisaburo Takashima, Takahiko Iizuka
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Patent number: 11651818Abstract: According to one embodiment, a memory device includes: a variable resistance memory region; a semiconductor layer; an insulating layer; first and second word lines; and a first select gate line. When information stored in the first memory cell is read, or when information is written into the first memory cell, after a voltage of the first select gate line is set to a first voltage and voltages of the first and second word lines are set to a second voltage, the voltage of the first select gate line is increased from the first voltage to a third voltage. After the voltage of the first select gate line is increased to at least the second voltage, the voltage of the first word line is decreased from the second voltage to the first voltage, and the voltage of the second word line is increased from the second voltage to a fourth voltage.Type: GrantFiled: July 27, 2021Date of Patent: May 16, 2023Assignee: KIOXIA CORPORATIONInventors: Ryu Ogiwara, Daisaburo Takashima, Takahiko Iizuka
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Publication number: 20230102229Abstract: According to one embodiment, a memory device includes a stacked structure including a plurality of conductive layers stacked to be apart from each other in a first direction, and a pillar structure including a resistance change portion extending in the first direction in the stacked structure, and a semiconductor portion which extends in the first direction in the stacked structure and which includes a first portion provided along the resistance change portion and a second portion extending from the first portion in at least one direction intersecting the first direction.Type: ApplicationFiled: March 14, 2022Publication date: March 30, 2023Applicant: Kioxia CorporationInventors: Yoshiki KAMATA, Yoshiaki ASAO, Yukihiro NOMURA, Misako MOROTA, Daisaburo TAKASHIMA, Takahiko IIZUKA, Shigeru KAWANAKA