Patents by Inventor Hirofumi Iikawa
Hirofumi Iikawa 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: 8941168Abstract: A semiconductor device includes an element isolation region having an element isolation insulating film therein; an active region delineated by the element isolation region; agate insulating film formed in the active region; a charge storage layer above the gate insulating film; and an interelectrode insulating film. The interelectrode insulating film is formed in a first region above an upper surface of the element isolation insulating film, a second region along a sidewall of the charge storage layer, and a third region above an upper surface of the charge storage layer. The interelectrode insulating film includes a stack of a first silicon oxide film, a first silicon nitride film, a second silicon oxide film, and a second silicon nitride film. A control electrode layer is formed above the interelectrode insulating film. The second silicon oxide film is thinner in the first region than in the third region.Type: GrantFiled: March 19, 2012Date of Patent: January 27, 2015Assignee: Kabushiki Kaisha ToshibaInventors: Kazuhiro Matsuo, Masayuki Tanaka, Hirofumi Iikawa
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Patent number: 8791521Abstract: A semiconductor device includes an interelectrode insulating film formed between a charge storage layer and a control electrode layer. The interelectrode insulating film is formed in a first region above an upper surface of an element isolation insulating film, a second region along a sidewall of the charge storage layer, and a third region above an upper surface of the charge storage layer. The interelectrode insulating film includes a first stack including a first silicon nitride film or a high dielectric constant film interposed between a first and a second silicon oxide film or a second stack including a second high dielectric constant film and a third silicon oxide film, and a second silicon nitride film formed between the control electrode layer and the first or the second stack. The second silicon nitride film is relatively thinner in the third region than in the first region.Type: GrantFiled: March 19, 2012Date of Patent: July 29, 2014Assignee: Kabushiki Kaisha ToshibaInventors: Koji Nakahara, Kazuhiro Matsuo, Masayuki Tanaka, Hirofumi Iikawa
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Patent number: 8546216Abstract: A nonvolatile semiconductor memory device includes a first insulating layer, charge storage layers, element isolation insulating films, and a second insulating layer formed on the charge storage layers and the element isolation insulating films and including a stacked structure of a first silicon nitride film, first silicon oxide film, intermediate insulating film and second silicon oxide film. The first silicon nitride film has a nitrogen concentration of not less than 21×1015 atoms/cm2. Each element isolation insulating film includes a high-temperature oxide film formed along lower side surfaces of the charge storage layers between the charge storage layers and a coating type insulating film. The first silicon nitride film is formed on an upper surface of the high-temperature oxide film in upper surfaces of the element isolation insulating films and not on the upper surface of the coating type insulating film.Type: GrantFiled: August 26, 2011Date of Patent: October 1, 2013Assignee: Kabushiki Kaisha ToshibaInventors: Hirofumi Iikawa, Masayuki Tanaka
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Patent number: 8471319Abstract: A semiconductor device is disclosed. The semiconductor device includes a semiconductor substrate; a gate insulating film formed above the semiconductor substrate; a charge storage layer formed above the gate insulating film; a multilayered interelectrode insulating film formed in a first region above an upper surface portion of the element isolation insulating film, a second region above a sidewall portion of the charge storage layer and a third region above an upper surface portion of the charge storage layer, the interelectrode insulating film including a stack of an upper silicon oxide film, a middle silicon nitride film, and a lower silicon oxide film; a control gate electrode formed above the interelectrode insulating film; wherein the middle silicon nitride film is thinner in the third region than in the second region and the upper silicon oxide film is thicker in the third region than in the second region.Type: GrantFiled: September 20, 2011Date of Patent: June 25, 2013Assignee: Kabushiki Kaisha ToshibaInventors: Kazuhiro Matsuo, Masayuki Tanaka, Hirofumi Iikawa
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Publication number: 20130069142Abstract: A semiconductor device includes an element isolation region having an element isolation insulating film therein; an active region delineated by the element isolation region; agate insulating film formed in the active region; a charge storage layer above the gate insulating film; and an interelectrode insulating film. The interelectrode insulating film is formed in a first region above an upper surface of the element isolation insulating film, a second region along a sidewall of the charge storage layer, and a third region above an upper surface of the charge storage layer. The interelectrode insulating film includes a stack of a first silicon oxide film, a first silicon nitride film, a second silicon oxide film, and a second silicon nitride film. A control electrode layer is formed above the interelectrode insulating film. The second silicon oxide film is thinner in the first region than in the third region.Type: ApplicationFiled: March 19, 2012Publication date: March 21, 2013Applicant: Kabushiki Kaisha ToshibaInventors: Kazuhiro MATSUO, Masayuki TANAKA, Hirofumi IIKAWA
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Publication number: 20130069135Abstract: A semiconductor device includes an interelectrode insulating film formed between a charge storage layer and a control electrode layer. The interelectrode insulating film is formed in a first region above an upper surface of an element isolation insulating film, a second region along a sidewall of the charge storage layer, and a third region above an upper surface of the charge storage layer. The interelectrode insulating film includes a first stack including a first silicon nitride film or a high dielectric constant film interposed between a first and a second silicon oxide film or a second stack including a second high dielectric constant film and a third silicon oxide film, and a second silicon nitride film formed between the control electrode layer and the first or the second stack. The second silicon nitride film is relatively thinner in the third region than in the first region.Type: ApplicationFiled: March 19, 2012Publication date: March 21, 2013Applicant: Kabushiki Kaisha ToshibaInventors: Koji Nakahara, Kazuhiro Matsuo, Masayuki Tanaka, Hirofumi Iikawa
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Publication number: 20120126299Abstract: A semiconductor device is disclosed. The semiconductor device includes a semiconductor substrate; a gate insulating film formed above the semiconductor substrate; a charge storage layer formed above the gate insulating film; a multilayered interelectrode insulating film formed in a first region above an upper surface portion of the element isolation insulating film, a second region above a sidewall portion of the charge storage layer and a third region above an upper surface portion of the charge storage layer, the interelectrode insulating film including a stack of an upper silicon oxide film, a middle silicon nitride film, and a lower silicon oxide film; a control gate electrode formed above the interelectrode insulating film; wherein the middle silicon nitride film is thinner in the third region than in the second region and the upper silicon oxide film is thicker in the third region than in the second region.Type: ApplicationFiled: September 20, 2011Publication date: May 24, 2012Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Kazuhiro MATSUO, Masayuki Tanaka, Hirofumi Iikawa
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Publication number: 20110312155Abstract: A nonvolatile semiconductor memory device includes a first insulating layer, charge storage layers, element isolation insulating films, and a second insulating layer formed on the charge storage layers and the element isolation insulating films and including a stacked structure of a first silicon nitride film, first silicon oxide film, intermediate insulating film and second silicon oxide film. The first silicon nitride film has a nitrogen concentration of not less than 21×1015 atoms/cm2. Each element isolation insulating film includes a high-temperature oxide film formed along lower side surfaces of the charge storage layers between the charge storage layers and a coating type insulating film. The first silicon nitride film is formed on an upper surface of the high-temperature oxide film in upper surfaces of the element isolation insulating films and not on the upper surface of the coating type insulating film.Type: ApplicationFiled: August 26, 2011Publication date: December 22, 2011Applicant: Kabushiki Kaisha ToshibaInventors: Hirofumi IIKAWA, Masayuki Tanaka
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Patent number: 8022467Abstract: A nonvolatile semiconductor memory device includes a first insulating layer, charge storage layers, element isolation insulating films, and a second insulating layer formed on the charge storage layers and the element isolation insulating films and including a stacked structure of a first silicon nitride film, first silicon oxide film, intermediate insulating film and second silicon oxide film. The first silicon nitride film has a nitrogen concentration of not less than 21×1015 atoms/cm2. Each element isolation insulating film includes a high-temperature oxide film formed along lower side surfaces of the charge storage layers between the charge storage layers and a coating type insulating film. The first silicon nitride film is formed on an upper surface of the high-temperature oxide film in upper surfaces of the element isolation insulating films and not on the upper surface of the coating type insulating film.Type: GrantFiled: May 18, 2009Date of Patent: September 20, 2011Assignee: Kabushiki Kaisha ToshibaInventors: Hirofumi Iikawa, Masayuki Tanaka
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Publication number: 20110133267Abstract: A method of fabricating a semiconductor device includes forming a gate insulating film on a semiconductor substrate, forming a charge accumulation layer, an intermediate insulating film and a conductive layer sequentially on the gate insulating film, forming an electrode isolating trench in the conductive layer, the intermediate insulating film and the charge accumulation layer, forming a nitride film on upper and side surfaces of the conductive layer, side surfaces of the intermediate insulating film, side surfaces of the charge accumulation layer and an upper surface of the gate insulating film, removing the nitride film formed on the upper surface of the gate insulating film, and filling the electrode isolating trench with an insulating film.Type: ApplicationFiled: September 1, 2010Publication date: June 9, 2011Applicant: Kabushiki Kaisha ToshibaInventors: Kazuhiro Matsuo, Masayuki Tanaka, Hirofumi Iikawa
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Publication number: 20100102377Abstract: A nonvolatile semiconductor memory device includes a semiconductor substrate, a first insulating layer formed on the semiconductor substrate, a plurality of charge storage layers formed on the first insulating layer, a plurality of element isolation insulating films formed between the charge storage layers respectively, a second insulating layer formed on the charge storage layers and the element isolation insulating films, the second insulating layer including a stacked structure of a first silicon nitride film, a first silicon oxide film, an intermediate insulating film having a relative dielectric constant of not less than 7 and a second silicon oxide film, and a control electrode formed on the second insulating layer. The first silicon nitride film has a nitrogen concentration of not less than 21×1015 atoms/cm2.Type: ApplicationFiled: May 18, 2009Publication date: April 29, 2010Applicant: Kabushiki Kaisha ToshibaInventors: Hirofumi IIKAWA, Masayuki Tanaka