Patents by Inventor Riichiro Shirota
Riichiro Shirota 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: 20130176783Abstract: TASK: to minimize variations of the threshold voltage distribution after programming and obtain a high-speed rewriting characteristic. MEANS FOR SOLVING THE PROBLEM: A non-volatile semiconductor memory device includes a non-volatile memory cell array and a control circuit for controlling writing-in to the memory cell array, wherein before or after an erasing process where data of written-in memory cells is erased, the control circuit detects a programming speed when writing-in to the memory cell array, determines a programming start voltage corresponding to the programming speed for every block or every word line, stores the determined programming start voltage in the memory cell array and reads-out the programming start voltage from the memory cell array to write-in predetermined data.Type: ApplicationFiled: June 19, 2012Publication date: July 11, 2013Inventors: Makoto SENOO, Hideki ARAKAWA, Riichiro SHIROTA
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Patent number: 8421143Abstract: Disclosure is semiconductor device of a selective gate region, comprising a semiconductor layer, a first insulating film formed on the semiconductor layer, a first electrode layer formed on the first insulating layer, an element isolating region comprising an element isolating insulating film formed to extend through the first electrode layer and the first insulating film to reach an inner region of the semiconductor layer, the element isolating region isolating a element region and being self-aligned with the first electrode layer, a second insulating film formed on the first electrode layer and the element isolating region, an open portion exposing a surface of the first electrode layer being formed in the second insulating film, and a second electrode layer formed on the second insulating film and the exposed surface of the first electrode layer, the second electrode layer being electronically connected to the first electrode layer via the open portion.Type: GrantFiled: March 15, 2012Date of Patent: April 16, 2013Assignee: Kabushiki Kaisha ToshibaInventors: Michiharu Matsui, Seiichi Mori, Riichiro Shirota, Yuji Takeuchi, Takeshi Kamigaichi
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Patent number: 8405139Abstract: Disclosure is semiconductor device of a selective gate region, comprising a semiconductor layer, a first insulating film formed on the semiconductor layer, a first electrode layer formed on the first insulating layer, an element isolating region comprising an element isolating insulating film formed to extend through the first electrode layer and the first insulating film to reach an inner region of the semiconductor layer, the element isolating region isolating a element region and being self-aligned with the first electrode layer, a second insulating film formed on the first electrode layer and the element isolating region, an open portion exposing a surface of the first electrode layer being formed in the second insulating film, and a second electrode layer formed on the second insulating film and the exposed surface of the first electrode layer, the second electrode layer being electronically connected to the first electrode layer via the open portion.Type: GrantFiled: April 13, 2011Date of Patent: March 26, 2013Assignee: Kabushiki Kaisha ToshibaInventors: Michiharu Matsui, Seiichi Mori, Riichiro Shirota, Yuji Takeuchi, Takeshi Kamigaichi
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Publication number: 20130003466Abstract: An application circuit and an operation method of a semiconductor device are provided. A leakage current among a control gate diffusion layer, a source diffusion layer and a drain is reduced by adjusting biases applied on a double well region, so as to reduce the product cost and improve the accuracy of a battery-less electronic timer that uses the semiconductor device.Type: ApplicationFiled: June 27, 2012Publication date: January 3, 2013Applicant: NATIONAL CHIAO TUNG UNIVERSITYInventors: Riichiro Shirota, Hiroshi Watanabe
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Patent number: 8324679Abstract: A nonvolatile semiconductor memory includes first and second memory cells having a floating gate and a control gate. The floating gate of the first and second memory cells is comprised a first part, and a second part arranged on the first part, and a width of the second part in an extending direction of the control gate is narrower than that of the first part. A first space between the first parts of the first and second memory cells is filled with one kind of an insulator. The control gate is arranged at a second space between the second parts of the first and second memory cells.Type: GrantFiled: March 26, 2012Date of Patent: December 4, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Masayuki Ichige, Fumitaka Arai, Riichiro Shirota, Toshitake Yaegashi, Yoshio Ozawa, Akihito Yamamoto, Ichiro Mizushima, Yoshihiko Saito
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Patent number: 8274827Abstract: The invention provides a memory device on a substrate. The memory device comprises semiconductor layers, common word lines, common bit lines and a common source line. The semiconductor layers are stacked on the substrate, wherein each semiconductor layer has a plurality of NAND strings, and each NAND string includes memory cells and at least a string selection transistor. The common word lines are configured above the semiconductor layers, wherein each common word line is coupled to the memory cells arranged in a same row of the semiconductor layers. The common bit lines are configured on the common word lines, wherein each common bit line is coupled to a first ends of the NAND strings arranged in the same column of the semiconductor layers. The common source line is configured on the common word lines and coupled to a second ends of the NAND strings of the semiconductor layers.Type: GrantFiled: May 17, 2010Date of Patent: September 25, 2012Assignee: RobustFlash Technologies Ltd.Inventors: Riichiro Shirota, Te-Chang Tseng
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Publication number: 20120181598Abstract: A nonvolatile semiconductor memory includes first and second memory cells having a floating gate and a control gate. The floating gate of the first and second memory cells is comprised a first part, and a second part arranged on the first part, and a width of the second part in an extending direction of the control gate is narrower than that of the first part. A first space between the first parts of the first and second memory cells is filled with one kind of an insulator. The control gate is arranged at a second space between the second parts of the first and second memory cells.Type: ApplicationFiled: March 26, 2012Publication date: July 19, 2012Inventors: Masayuki ICHIGE, Fumitaka Arai, Riichiro Shirota, Toshitake Yaegashi, Yoshio Ozawa, Akihito Yamamoto, Ichiro Mizushima, Yoshihiko Saito
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Patent number: 8223541Abstract: A non-volatile semiconductor memory and a writing method thereof are provided for preventing miswriting induced by gate-induced-drain leakage (GIDL). The non-volatile semiconductor memory comprises a non-volatile memory cell array 10 for recording multiple values by setting a plurality of different thresholds to each memory cell transistor that is connected in series between selection transistors Qs1 and Qs2 on two terminals of a selected bit line; and a control circuit 11 for controlling writing of the data from the memory cell array 10. The control circuit 11 records two values for at least a plurality of first memory cell transistors Q0, Q1, Q32 and Q33 respectively adjacent to the selection transistors Qs1 and Qs2 on two terminals of the bit line, and records more than three values for a plurality of second transistors Q2˜Q31 other than the first memory cell transistors.Type: GrantFiled: December 3, 2009Date of Patent: July 17, 2012Assignee: Powerchip Technology CorporationInventor: Riichiro Shirota
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Patent number: 8223558Abstract: A NAND cell unit includes memory cells which are connected in series. An erase operation is effected on all memory cells. Then, a soft-program voltage, which is opposite in polarity to the erase voltage applied in an erase operation, is applied to all memory cells, thereby setting all memory cells out of an over-erased state. Thereafter, a program voltage of 20V is applied to the control gate of a selected memory cell, 0V is applied to the control gates of the two memory cells provided adjacent to the selected memory cell, and 11V is applied to the control gates of the remaining memory cells. Data is thereby programmed into the selected memory cell. The time for which the program voltage is applied to the selected memory cell is adjusted in accordance with the data to be programmed into the selected memory cell. Hence, data “0” can be correctly programmed into the selected memory cell, multi-value data can be read from any selected memory cell at high speed.Type: GrantFiled: July 11, 2011Date of Patent: July 17, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Tomoharu Tanaka, Hiroshi Nakamura, Ken Takeuchi, Riichiro Shirota, Fumitaka Arai, Susumu Fujimura
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Publication number: 20120168846Abstract: Disclosure is semiconductor device of a selective gate region, comprising a semiconductor layer, a first insulating film formed on the semiconductor layer, a first electrode layer formed on the first insulating layer, an element isolating region comprising an element isolating insulating film formed to extend through the first electrode layer and the first insulating film to reach an inner region of the semiconductor layer, the element isolating region isolating a element region and being self-aligned with the first electrode layer, a second insulating film formed on the first electrode layer and the element isolating region, an open portion exposing a surface of the first electrode layer being formed in the second insulating film, and a second electrode layer formed on the second insulating film and the exposed surface of the first electrode layer, the second electrode layer being electronically connected to the first electrode layer via the open portion.Type: ApplicationFiled: March 15, 2012Publication date: July 5, 2012Inventors: Michiharu MATSUI, Seiichi Mori, Riichiro Shirota, Yuji Takeuchi, Takeshi Kamigaichi
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Patent number: 8148216Abstract: A nonvolatile semiconductor memory of an aspect of the present invention comprises a semiconductor substrate, a pillar-shaped semiconductor layer extending in the vertical direction with respect to the surface of the semiconductor substrate, a plurality of memory cells arranged in the vertical direction on the side surface of the semiconductor layer and having a charge storage layer and a control gate electrode, a first select gate transistor arranged on the semiconductor layer at an end of the memory cells on the side of the semiconductor substrate, and a second select gate transistor arranged on the semiconductor layer on the other end of the memory cells opposite to the side of the semiconductor substrate, wherein the first select gate transistor includes a diffusion layer in the semiconductor substrate and is electrically connected to the pillar-shaped semiconductor layer by way of the diffusion layer that serves as the drain region.Type: GrantFiled: December 21, 2010Date of Patent: April 3, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Fumitaka Arai, Riichiro Shirota
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Publication number: 20110310666Abstract: In a programming method for a NAND flash memory device, a self-boosting scheme is used to eliminate excess electrons in the channel of an inhibit cell string that would otherwise cause programming disturb. The elimination is enabled by applying a negative voltage to word lines connected to the inhibit cell string before boosting the channel, and this leads to bringing high program immunity. A row decoder circuitry to achieve the programming operation and a file system architecture based on the programming scheme to improve the efficiency of file management are also described.Type: ApplicationFiled: April 30, 2009Publication date: December 22, 2011Inventors: Takashi Miida, Riichiro Shirota, Hideki Arakawa, Ching Sung Yang, Tzung Ling Lin
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Publication number: 20110280075Abstract: The invention provides a memory device on a substrate. The memory device comprises semiconductor layers, common word lines, common bit lines and a common source line. The semiconductor layers are stacked on the substrate, wherein each semiconductor layer has a plurality of NAND strings, and each NAND string includes memory cells and at least a string selection transistor. The common word lines are configured above the semiconductor layers, wherein each common word line is coupled to the memory cells arranged in a same row of the semiconductor layers. The common bit lines are configured on the common word lines, wherein each common bit line is coupled to a first ends of the NAND strings arranged in the same column of the semiconductor layers. The common source line is configured on the common word lines and coupled to a second ends of the NAND strings of the semiconductor layers.Type: ApplicationFiled: May 17, 2010Publication date: November 17, 2011Applicant: RobustFlash Technologies Ltd.Inventors: Riichiro Shirota, Te-Chang Tseng
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Publication number: 20110272745Abstract: A semiconductor memory includes a plurality of stripe-like active areas formed by stacking, in a direction perpendicular to a substrate, a plurality of layers extending parallel to the substrate, a first gate electrode formed on first side surfaces of the active areas, the first side surfaces being perpendicular to the substrate, a second gate electrode formed on second side surfaces of the active areas, the second side surfaces being perpendicular to the substrate. The layers are patterned in self-alignment with each other, intersections of the active areas and the first gate electrode form a plurality of memory cells, and the plurality of memory cells in an intersecting plane share the first gate electrode.Type: ApplicationFiled: July 19, 2011Publication date: November 10, 2011Applicant: Kabushiki Kaisha ToshibaInventors: Masahiro Kiyotoshi, Akihito Yamamoto, Yoshio Ozawa, Fumitaka Arai, Riichiro Shirota
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Publication number: 20110267886Abstract: A NAND cell unit includes memory cells which are connected in series. An erase operation is effected on all memory cells. Then, a soft-program voltage, which is opposite in polarity to the erase voltage applied in an erase operation, is applied to all memory cells, thereby setting all memory cells out of an over-erased state. Thereafter, a program voltage of 20V is applied to the control gate of a selected memory cell, 0V is applied to the control gates of the two memory cells provided adjacent to the selected memory cell, and 11V is applied to the control gates of the remaining memory cells. Data is thereby programmed into the selected memory cell. The time for which the program voltage is applied to the selected memory cell is adjusted in accordance with the data to be programmed into the selected memory cell. Hence, data “0” can be correctly programmed into the selected memory cell, multi-value data can be read from any selected memory cell at high speed.Type: ApplicationFiled: July 11, 2011Publication date: November 3, 2011Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Tomoharu Tanaka, Hiroshi Nakamura, Ken Takeuchi, Riichiro Shirota, Fumitaka Arai, Susumu Fujimura
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Patent number: 8048741Abstract: A semiconductor memory device includes: a semiconductor substrate, on which an impurity diffusion layer is formed in a cell array area; a gate wiring stack body formed on the cell array area, in which multiple gate wirings are stacked and separated from each other with insulating films; a gate insulating film formed on the side surface of the gate wiring stack body, in which an insulating charge storage layer is contained; pillar-shaped semiconductor layers arranged along the gate wiring stack body, one side surfaces of which are opposed to the gate wiring stack body via the gate insulating film, each pillar-shaped semiconductor layer having the same conductivity type as the impurity diffusion layer; and data lines formed to be in contact with the upper surfaces of the pillar-shaped semiconductor layers and intersect the gate wirings.Type: GrantFiled: March 2, 2010Date of Patent: November 1, 2011Assignee: Kabushiki Kaisha ToshibaInventors: Fumitaka Arai, Riichiro Shirota, Makoto Mizukami
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Patent number: 8008732Abstract: A semiconductor memory includes a plurality of stripe-like active areas formed by stacking, in a direction perpendicular to a substrate, a plurality of layers extending parallel to the substrate, a first gate electrode formed on first side surfaces of the active areas, the first side surfaces being perpendicular to the substrate, a second gate electrode formed on second side surfaces of the active areas, the second side surfaces being perpendicular to the substrate. The layers are patterned in self-alignment with each other, intersections of the active areas and the first gate electrode form a plurality of memory cells, and the plurality of memory cells in an intersecting plane share the first gate electrode.Type: GrantFiled: September 20, 2007Date of Patent: August 30, 2011Assignee: Kabushiki Kaisha ToshibaInventors: Masahiro Kiyotoshi, Akihito Yamamoto, Yoshio Ozawa, Fumitaka Arai, Riichiro Shirota
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Patent number: 8000147Abstract: A NAND cell unit includes memory cells which are connected in series. An erase operation is effected on all memory cells. Then, a soft-program voltage, which is opposite in polarity to the erase voltage applied in an erase operation, is applied to all memory cells, thereby setting all memory cells out of an over-erased state. Thereafter, a program voltage of 20V is applied to the control gate of a selected memory cell, 0V is applied to the control gates of the two memory cells provided adjacent to the selected memory cell, and 11V is applied to the control gates of the remaining memory cells. Data is thereby programmed into the selected memory cell. The time for which the program voltage is applied to the selected memory cell is adjusted in accordance with the data to be programmed into the selected memory cell. Hence, data “0” can be correctly programmed into the selected memory cell, multi-value data can be read from any selected memory cell at high speed.Type: GrantFiled: May 17, 2010Date of Patent: August 16, 2011Assignee: Kabushiki Kaisha ToshibaInventors: Tomoharu Tanaka, Hiroshi Nakamura, Ken Takeuchi, Riichiro Shirota, Fumitaka Arai, Susumu Fujimura
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Publication number: 20110186921Abstract: Disclosure is semiconductor device of a selective gate region, comprising a semiconductor layer, a first insulating film formed on the semiconductor layer, a first electrode layer formed on the first insulating layer, an element isolating region comprising an element isolating insulating film formed to extend through the first electrode layer and the first insulating film to reach an inner region of the semiconductor layer, the element isolating region isolating a element region and being self-aligned with the first electrode layer, a second insulating film formed on the first electrode layer and the element isolating region, an open portion exposing a surface of the first electrode layer being formed in the second insulating film, and a second electrode layer formed on the second insulating film and the exposed surface of the first electrode layer, the second electrode layer being electronically connected to the first electrode layer via the open portion.Type: ApplicationFiled: April 13, 2011Publication date: August 4, 2011Inventors: Michiharu MATSUI, Seiichi Mori, Riichiro Shirota, Yuji Takeuchi, Takeshi Kamigaichi
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Patent number: 7982259Abstract: A nonvolatile semiconductor memory includes first and second memory cells having a floating gate and a control gate. The floating gate of the first and second memory cells is comprised a first part, and a second part arranged on the first part, and a width of the second part in an extending direction of the control gate is narrower than that of the first part. A first space between the first parts of the first and second memory cells is filled with one kind of an insulator. The control gate is arranged at a second space between the second parts of the first and second memory cells.Type: GrantFiled: March 19, 2007Date of Patent: July 19, 2011Assignee: Kabushiki Kaisha ToshibaInventors: Masayuki Ichige, Fumitaka Arai, Riichiro Shirota, Toshitake Yaegashi, Yoshio Ozawa, Akihito Yamamoto, Ichiro Mizushima, Yoshihiko Saito