Patents by Inventor Wakako Takeuchi

Wakako Takeuchi 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).

  • Patent number: 8450787
    Abstract: A nonvolatile semiconductor memory has a semiconductor substrate, a first insulating film formed on a channel region on a surface portion of the semiconductor substrate, a charge accumulating layer formed on the first insulating film, a second insulating film formed on the charge accumulating layer, a control gate electrode formed on the second insulating film, and a third insulating film including an Si—N bond that is formed on a bottom surface and side surfaces of the charge accumulating layer.
    Type: Grant
    Filed: October 20, 2011
    Date of Patent: May 28, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi Akahori, Wakako Takeuchi
  • Patent number: 8330206
    Abstract: A memory device includes a semiconductor substrate, memory elements formed above the substrate in rows and columns, bit lines and word lines selectively connected with the memory elements in the respective columns and rows, each memory element including, a first gate insulator formed above the substrate, a charge accumulation layer formed on the first gate insulator, a second gate insulator formed on the charge accumulation layer, and a control electrode formed on the second gate insulator, wherein a ratio r/d is not smaller than 0.5, where r: a radius of curvature of an upper corner portion or surface roughness of the charge accumulation layer and d: an equivalent oxide thickness of the second gate insulator in a cross section along a direction vertical to the bit lines.
    Type: Grant
    Filed: February 14, 2012
    Date of Patent: December 11, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi Akahori, Wakako Takeuchi, Atsuhiro Sato
  • Publication number: 20120139032
    Abstract: A memory device includes a semiconductor substrate, memory elements formed above the substrate in rows and columns, bit lines and word lines selectively connected with the memory elements in the respective columns and rows, each memory element including, a first gate insulator formed above the substrate, a charge accumulation layer formed on the first gate insulator, a second gate insulator formed on the charge accumulation layer, and a control electrode formed on the second gate insulator, wherein a ratio r/d is not smaller than 0.5, where r: a radius of curvature of an upper corner portion or surface roughness of the charge accumulation layer and d: an equivalent oxide thickness of the second gate insulator in a cross section along a direction vertical to the bit lines.
    Type: Application
    Filed: February 14, 2012
    Publication date: June 7, 2012
    Inventors: Hiroshi AKAHORI, Wakako Takeuchi, Atsuhiro Sato
  • Patent number: 8153487
    Abstract: A semiconductor device includes a semiconductor substrate, a first insulating film provided on the semiconductor substrate, a charge storage layer provided on the first insulating film, a second insulating film comprising a plurality of insulating films provided on the charge storage layer and comprising a nitride film as an uppermost layer, and a single-layer control gate electrode provided on the second insulating film and comprising metal silicide.
    Type: Grant
    Filed: March 10, 2010
    Date of Patent: April 10, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Wakako Takeuchi, Hiroshi Akahori, Murato Kawai
  • Patent number: 8133782
    Abstract: A memory device includes a semiconductor substrate, memory elements formed above the substrate in rows and columns, bit lines and word lines selectively connected with the memory elements in the respective columns and rows, each memory element including, a first gate insulator formed above the substrate, a charge accumulation layer formed on the first gate insulator, a second gate insulator formed on the charge accumulation layer, and a control electrode formed on the second gate insulator, wherein a ratio r/d is not smaller than 0.5, where r: a radius of curvature of an upper corner portion or surface roughness of the charge accumulation layer and d: an equivalent oxide thickness of the second gate insulator in a cross section along a direction vertical to the bit lines.
    Type: Grant
    Filed: February 16, 2011
    Date of Patent: March 13, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi Akahori, Wakako Takeuchi, Atsuhiro Sato
  • Publication number: 20120032253
    Abstract: A nonvolatile semiconductor memory has a semiconductor substrate, a first insulating film formed on a channel region on a surface portion of the semiconductor substrate, a charge accumulating layer formed on the first insulating film, a second insulating film formed on the charge accumulating layer, a control gate electrode formed on the second insulating film, and a third insulating film including an Si—N bond that is formed on a bottom surface and side surfaces of the charge accumulating layer.
    Type: Application
    Filed: October 20, 2011
    Publication date: February 9, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi Akahori, Wakako Takeuchi
  • Patent number: 8071444
    Abstract: A nonvolatile semiconductor memory has a semiconductor substrate, a first insulating film formed on a channel region on a surface portion of the semiconductor substrate, a charge accumulating layer formed on the first insulating film, a second insulating film formed on the charge accumulating layer, a control gate electrode formed on the second insulating film, and a third insulating film including an Si—N bond that is formed on a bottom surface and side surfaces of the charge accumulating layer.
    Type: Grant
    Filed: September 30, 2010
    Date of Patent: December 6, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi Akahori, Wakako Takeuchi
  • Publication number: 20110163368
    Abstract: A nonvolatile semiconductor memory device having high charge retention characteristics and capable of improving leakage characteristics of a dielectric film disposed between a charge storage layer and a control gate electrode, and manufacturing method thereof is disclosed. According to one aspect, there is provided a semiconductor memory device comprising a first electrode disposed on a first insulator on a semiconductor substrate, a second insulator disposed on the first electrode, a second electrode disposed on the second insulator, and diffusion layers disposed in the semiconductor substrate, wherein the second insulator including a silicon-rich silicon nitride film containing more silicon than that in a stoichiometric silicon nitride film, and a silicon oxide film formed on the silicon-rich silicon nitride film, and wherein the silicon-rich silicon nitride film has a ratio of a silicon concentration and a nitrogen concentration set to 1:0.9 to 1:1.2.
    Type: Application
    Filed: March 17, 2011
    Publication date: July 7, 2011
    Inventors: Wakako TAKEUCHI, Hiroshi Akahori, Atsuhiro Sato
  • Publication number: 20110136330
    Abstract: A memory device includes a semiconductor substrate, memory elements formed above the substrate in rows and columns, bit lines and word lines selectively connected with the memory elements in the respective columns and rows, each memory element including, a first gate insulator formed above the substrate, a charge accumulation layer formed on the first gate insulator, a second gate insulator formed on the charge accumulation layer, and a control electrode formed on the second gate insulator, wherein a ratio r/d is not smaller than 0.5, where r: a radius of curvature of an upper corner portion or surface roughness of the charge accumulation layer and d: an equivalent oxide thickness of the second gate insulator in a cross section along a direction vertical to the bit lines.
    Type: Application
    Filed: February 16, 2011
    Publication date: June 9, 2011
    Inventors: Hiroshi AKAHORI, Wakako TAKEUCHI, Atsuhiro SATO
  • Patent number: 7928496
    Abstract: A nonvolatile semiconductor memory device having high charge retention characteristics and capable of improving leakage characteristics of a dielectric film disposed between a charge storage layer and a control gate electrode, and manufacturing method thereof is disclosed. According to one aspect, there is provided a semiconductor memory device comprising a first electrode disposed on a first insulator on a semiconductor substrate, a second insulator disposed on the first electrode, a second electrode disposed on the second insulator, and diffusion layers disposed in the semiconductor substrate, wherein the second insulator including a silicon-rich silicon nitride film containing more silicon than that in a stoichiometric silicon nitride film, and a silicon oxide film formed on the silicon-rich silicon nitride film, and wherein the silicon-rich silicon nitride film has a ratio of a silicon concentration and a nitrogen concentration set to 1:0.9 to 1:1.2.
    Type: Grant
    Filed: June 7, 2007
    Date of Patent: April 19, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Wakako Takeuchi, Hiroshi Akahori, Atsuhiro Sato
  • Patent number: 7906804
    Abstract: A memory device includes a semiconductor substrate, memory elements formed above the substrate in rows and columns, bit lines and word lines selectively connected with the memory elements in the respective columns and rows, each memory element including, a first gate insulator formed above the substrate, a charge accumulation layer formed on the first gate insulator, a second gate insulator formed on the charge accumulation layer, and a control electrode formed on the second gate insulator, wherein a ratio r/d is not smaller than 0.5, where r: a radius of curvature of an upper corner portion or surface roughness of the charge accumulation layer and d: an equivalent oxide thickness of the second gate insulator in a cross section along a direction vertical to the bit lines.
    Type: Grant
    Filed: May 17, 2007
    Date of Patent: March 15, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi Akahori, Wakako Takeuchi, Atsuhiro Sato
  • Publication number: 20110020995
    Abstract: A nonvolatile semiconductor memory has a semiconductor substrate, a first insulating film formed on a channel region on a surface portion of the semiconductor substrate, a charge accumulating layer formed on the first insulating film, a second insulating film formed on the charge accumulating layer, a control gate electrode formed on the second insulating film, and a third insulating film including an Si—N bond that is formed on a bottom surface and side surfaces of the charge accumulating layer.
    Type: Application
    Filed: September 30, 2010
    Publication date: January 27, 2011
    Inventors: Hiroshi Akahori, Wakako Takeuchi
  • Patent number: 7829950
    Abstract: A nonvolatile semiconductor memory has a semiconductor substrate, a first insulating film formed on a channel region on a surface portion of the semiconductor substrate, a charge accumulating layer formed on the first insulating film, a second insulating film formed on the charge accumulating layer, a control gate electrode formed on the second insulating film, and a third insulating film including an Si—N bond that is formed on a bottom surface and side surfaces of the charge accumulating layer.
    Type: Grant
    Filed: February 26, 2008
    Date of Patent: November 9, 2010
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi Akahori, Wakako Takeuchi
  • Patent number: 7821056
    Abstract: A nonvolatile semiconductor memory device includes an array of nonvolatile memory cell transistors, each of which is configured such that a tunnel insulation film, a floating gate electrode, a floating gate insulation film and a control gate electrode are stacked on a surface of a semiconductor substrate. A mean roughness of an interface between a polysilicon, of which the floating gate electrode is formed, and the floating gate insulation film is 1.5 nm or less.
    Type: Grant
    Filed: September 20, 2007
    Date of Patent: October 26, 2010
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi Akahori, Wakako Takeuchi
  • Publication number: 20100184275
    Abstract: A semiconductor device includes a semiconductor substrate, a first insulating film provided on the semiconductor substrate, a charge storage layer provided on the first insulating film, a second insulating film comprising a plurality of insulating films provided on the charge storage layer and comprising a nitride film as an uppermost layer, and a single-layer control gate electrode provided on the second insulating film and comprising metal silicide.
    Type: Application
    Filed: March 10, 2010
    Publication date: July 22, 2010
    Inventors: Wakako Takeuchi, Hiroshi Akahori, Murato Kawai
  • Publication number: 20100102448
    Abstract: A semiconductor device according to one embodiment includes: a semiconductor element formed on a semiconductor substrate; a metal wiring formed above the semiconductor element; an amorphous silicon film formed above the semiconductor element, the amorphous silicon film being insulated from the metal wiring; and a metal diffusion blocking film formed above the amorphous silicon film, the metal diffusion blocking film having a property to suppress diffusion of metal atoms in the metal wiring.
    Type: Application
    Filed: October 21, 2009
    Publication date: April 29, 2010
    Inventors: Hiroshi Akahori, Tooru Ichikawa, Wakako Takeuchi
  • Patent number: 7651914
    Abstract: A manufacturing method of a nonvolatile semiconductor memory device including: providing a first insulating film and a silicon film on a semiconductor substrate; providing a fifth insulating film containing silicon and oxygen on the silicon film; providing a second insulating film containing silicon and nitrogen on the fifth insulating film; providing a third insulating film on the second insulating film, the third insulating film is composed of a single-layer insulating film containing oxygen or multiple-layer stacked insulating film at least whose films on a top layer and a bottom layer contain oxygen, and relative dielectric constant of the single-layer insulating film and the stacked insulating film being larger than relative dielectric constant of a silicon oxide film; providing a fourth insulating film containing silicon and nitrogen on the third insulating film; and providing a control gate above the fourth insulating film.
    Type: Grant
    Filed: July 21, 2008
    Date of Patent: January 26, 2010
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi Akahori, Wakako Takeuchi, Yoshio Ozawa
  • Publication number: 20090218615
    Abstract: A semiconductor device according to an embodiment of the present invention has a bit line and a word line. The device includes a substrate, a first gate insulation film formed on the substrate, a charge storage layer formed on the first gate insulation film, a second gate insulation film formed on the charge storage layer, and a gate electrode formed on the second gate insulation film, the width between side surfaces of the second gate insulation film in the bit line direction being smaller than the width between side surfaces of the gate electrode in the bit line direction.
    Type: Application
    Filed: March 3, 2009
    Publication date: September 3, 2009
    Inventors: Wakako TAKEUCHI, Hiroshi Akahori, Masaki Kondo
  • Publication number: 20090194807
    Abstract: A semiconductor memory device includes: a semiconductor substrate; an element isolation trench formed on the semiconductor substrate so as to surround an element region in which a memory element is to be formed; a first gate insulating film formed on the element region of the semiconductor substrate; a charge storing layer formed on the first gate insulating film; a second gate insulating film formed on the charge storing layer; a control electrode formed on the second gate insulating film; an impurity diffusion layer formed in a surface layer of the semiconductor substrate along a channel direction of the charge storing layer; a sidewall oxide film formed on a side surface of the element isolation trench; and an element isolation insulating film formed so as to fill the element isolation trench together with the element isolation insulation film; wherein the top surface of the sidewall oxide film is flush with or above the top surface of the first gate insulating film.
    Type: Application
    Filed: October 11, 2007
    Publication date: August 6, 2009
    Inventors: Wakako Takeuchi, Hiroshi Akahori, Hiroki Yamashita
  • Publication number: 20090011586
    Abstract: A nonvolatile semiconductor memory device includes a first insulating film provided on a surface of a semiconductor substrate, a charge accumulation layer provided on the first insulating film, a second insulating film provided above the charge accumulation layer and contains silicon and nitrogen, a third insulating film provided on the second insulating film, and composed of a single-layer insulating film containing oxygen or a plural-layer stacked insulating film at least whose films on a top layer and a bottom layer contain oxygen, relative dielectric constant thereof being larger than it of a silicon oxide film, a fourth insulating film provided on the third insulating film and contains silicon and nitrogen, a control gate provided above the fourth insulating film, and a fifth insulating film provided between the charge accumulation layer and the second insulating film or between the fourth insulating film and the control gate, and contains silicon and oxygen.
    Type: Application
    Filed: July 21, 2008
    Publication date: January 8, 2009
    Inventors: Hiroshi Akahori, Wakako Takeuchi, Yoshio Ozawa