Patents by Inventor Toshiyuki Enda

Toshiyuki Enda 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).

  • Publication number: 20080253181
    Abstract: A method for programming a semiconductor memory device including such a program sequence as to program target threshold levels constituting multi-level data into multiple memory cells, which are simultaneously selected, wherein the program sequence is controlled to finish programming the multiple memory cells in order of height of the target threshold levels.
    Type: Application
    Filed: April 2, 2008
    Publication date: October 16, 2008
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Toshiaki Edahiro, Takuya Futatsuyama, Toshiyuki Enda
  • Publication number: 20080179659
    Abstract: A nonvolatile semiconductor memory device relating to one embodiment of this invention includes a substrate, a plurality of memory strings formed on said substrate, said memory string having a first select gate transistor, a plurality of memory cells and a second select gate transistor, said first select gate transistor having a first pillar semiconductor, a first gate insulation layer formed around said first pillar semiconductor and a first gate electrode being formed around said first gate insulation layer; said memory cell having a second pillar semiconductor, a first insulation layer formed around said second pillar semiconductor, a storage layer formed around said first insulation layer, a second insulation layer formed around said storage layer and first to nth electrodes (n is a natural number 2 or more) being formed around said second insulation layer, said first to nth electrodes being spread in two dimensions respectively, said second select gate transistor having a third pillar semiconductor, a se
    Type: Application
    Filed: January 28, 2008
    Publication date: July 31, 2008
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Toshiyuki Enda, Hiroyoshi Tanimoto, Takashi Izumida
  • Patent number: 7393748
    Abstract: A NAND cell unit is formed with an advanced gate forming process on a semiconductor layer of a first conductivity type, which is formed on a semiconductor substrate of the first conductivity type with an insulating film interposed therebetween. First impurity-doped layers of a second conductivity type are formed on the semiconductor layer, which serve as channel regions of the select gate transistors Bit line contact- and source line contact-use second impurity-doped layers of the first conductivity type are formed at bit line and source line contact portions, sidewalls of which are covered with an insulating film.
    Type: Grant
    Filed: December 12, 2006
    Date of Patent: July 1, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Fumitaka Arai, Toshiyuki Enda, Hiroyoshi Tanimoto, Naoki Kusunoki, Nobutoshi Aoki, Riichiro Shirota, Hiroshi Watanabe, Takamitsu Ishihara
  • Publication number: 20070290253
    Abstract: A nonvolatile semiconductor memory device includes: a semiconductor region; device isolation regions placed in the semiconductor region and extending in a column direction; a semiconductor layer placed on the semiconductor region and between the device isolation regions, and having a convex shape in cross section along a row direction; source/drain regions placed in the semiconductor layer and spaced from each other; a gate insulating film placed on the semiconductor layer between the source/drain regions; a floating gate electrode layer placed on the gate insulating film; an intergate insulating film placed on the floating gate electrode layer and upper surfaces of the device isolation regions; and a control gate electrode layer placed on the intergate insulating film and extending in the row direction.
    Type: Application
    Filed: June 20, 2007
    Publication date: December 20, 2007
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Masaru KITO, Nobutoshi Aoki, Masaru Kidoh, Ryota Katsumata, Masaki Kondo, Naoki Kusunoki, Toshiyuki Enda, Sanae Ito, Hiroyoshi Tanimoto, Hideaki Aochi, Akihiro Nitayama, Riichiro Shirota
  • Publication number: 20070237002
    Abstract: A non-volatile semiconductor memory includes a plurality of memory cell transistors, each of the plurality of memory cell transistors includes: a source region having a first conductivity type and in contact with a buried insulating layer on a supporting substrate; a drain region having the first conductivity type and in contact with the buried insulating layer; and a channel region having the first conductivity type and provided between the source region and the drain region so as to contact the buried insulating layer, wherein a thickness of the channel region is more than one nm and not more than a value obtained by adding seven nm to a half value of a gate length of the memory cell transistor.
    Type: Application
    Filed: June 14, 2007
    Publication date: October 11, 2007
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Toshiyuki Enda, Hiroyoshi Tanimoto, Naoki Kusunoki, Nobutoshi Aoki, Fumitaka Arai, Riichiro Shirota
  • Publication number: 20070138536
    Abstract: A NAND cell unit is formed with an advanced gate forming process on a semiconductor layer of a first conductivity type, which is formed on a semiconductor substrate of the first conductivity type with an insulating film interposed therebetween. First impurity-doped layers of a second conductivity type are formed on the semiconductor layer, which serve as channel regions of the select gate transistors Bit line contact- and source line contact-use second impurity-doped layers of the first conductivity type are formed at bit line and source line contact portions, sidewalls of which are covered with an insulating film.
    Type: Application
    Filed: December 12, 2006
    Publication date: June 21, 2007
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Fumitaka ARAI, Toshiyuki Enda, Hiroyoshi Tanimoto, Naoki Kusunoki, Nobutoshi Aoki, Riichiro Shirota, Hiroshi Watanabe, Takamitsu Ishihara
  • Publication number: 20070102749
    Abstract: A semiconductor memory device includes: a semiconductor substrate; a semiconductor layer formed on the semiconductor substrate with an insulating film interposed therebetween, the semiconductor layer being in contact with the semiconductor substrate via an opening formed in the insulating film; and a NAND cell unit formed on the semiconductor layer with a plurality of electrically rewritable and non-volatile memory cells connected in series and first and second select gate transistors disposed at both ends thereof.
    Type: Application
    Filed: October 16, 2006
    Publication date: May 10, 2007
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Riichiro Shirota, Fumitaka Arai, Toshiyuki Enda, Hiroyoshi Tanimoto, Naoki Kusunokii, Nobutoshi Aoki, Makoto Mizukami, Kiyotaka Miyano, Ichiro Mizushima
  • Publication number: 20060237706
    Abstract: A non-volatile semiconductor memory including a plurality of memory cell transistors, each of the plurality of memory cell transistors includes: a source region having a first conductivity type and in contact with a buried insulating layer on a supporting substrate; a drain-region having the first conductivity type and in contact with the buried insulating layer; and a channel region having the first conductivity type and provided between the source region and the drain region so as to contact the buried insulating layer, wherein a thickness of the channel region is more than one nm and not more than a value obtained by adding seven nm to a half value of a gate length of the memory cell transistor.
    Type: Application
    Filed: April 5, 2006
    Publication date: October 26, 2006
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Toshiyuki Enda, Hiroyoshi Tanimoto, Naoki Kusunoki, Nobutoshi Aoki, Fumitaka Arai, Riichiro Shirota
  • Patent number: 6784006
    Abstract: A method of manufacturing a semiconductor device, comprises: forming a semiconductor element in a semiconductor active region, and calculating the generation rate of electron hole pairs generated due to impact ionization caused in the semiconductor element; calculating a volume integral of the generation rate at least in an area where the impact ionization is caused; evaluating time-dependent degradations of electrical characteristics of the semiconductor element on the basis of the volume integral; and manufacturing a semiconductor device on the basis of the evaluation.
    Type: Grant
    Filed: December 5, 2001
    Date of Patent: August 31, 2004
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroyoshi Tanimoto, Toshiyuki Enda
  • Publication number: 20030073256
    Abstract: A method of manufacturing a semiconductor device, comprises: forming a semiconductor element in a semiconductor active region, and calculating the generation rate of electron hole pairs generated due to impact ionization caused in the semiconductor element; calculating a volume integral of the generation rate at least in an area where the impact ionization is caused; evaluating time-dependent degradations of electrical characteristics of the semiconductor element on the basis of the volume integral; and manufacturing a semiconductor device on the basis of the evaluation.
    Type: Application
    Filed: December 5, 2001
    Publication date: April 17, 2003
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Hiroyoshi Tanimoto, Toshiyuki Enda
  • Patent number: 6304834
    Abstract: A semiconductor device simulator having a grid generator, a quasi-Fermi potential setting unit, a bias setting unit, a coefficient matrix and residual vector setting unit and a matrix calculator is disclosed. A grid generator defines a finite number of grid points inside and around a semiconductor device, and generates a plurality of grids. A quasi-Fermi potential setting unit sets said linear quasi-Fermi potentials, which is linearly changing, at each section inside the generated grid. A bias setting unit defines the terminal bias to be applied to predetermined electrode regions. A coefficient matrix and residual vector setting unit obtains carrier concentration inside each grid from the quasi-Fermi potential, and sets coefficient matrix/residual vector for the basic equations. A matrix calculator calculates this coefficient matrix, and accordingly obtains the solution for the Poisson's equation and the carrier continuity equations to obtain the device behavior.
    Type: Grant
    Filed: September 14, 1999
    Date of Patent: October 16, 2001
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Toshiyuki Enda
  • Patent number: 6195790
    Abstract: A &Dgr;Z calculator calculates difference between an inversion layer capacitance by a classical theory and an inversion layer capacitance by a quantum theory, calculates &Dgr;Z which is a thickness of a semiconductor substrate equivalent to the difference in inversion layer capacitance. A discretization mesh generator generates a Delaunay discretization mesh for a structure of the semiconductor device to be evaluated. An electrical parameter calculator calculates electrical parameters of the semiconductor device under constraint that a charge density of channel conductivity type of the semiconductor device is set to zero at discretization mesh points of the discretization mesh on an interface between an insulating film and the semiconductor substrate and at discretization mesh points of the discretization mesh in the semiconductor substrate which are located within a distance less than the stored &Dgr;Z from the interface between the insulating film and the semiconductor substrate.
    Type: Grant
    Filed: April 17, 1998
    Date of Patent: February 27, 2001
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroyoshi Tanimoto, Toshiyuki Enda, Naoyuki Shigyo, Kazuya Matsuzawa
  • Patent number: 6051452
    Abstract: A silicon oxide layer serving as an insulation layer is formed on a p-type semiconductor substrate. An n.sup.+ -type source and drain regions are formed on the p-type substrate 110 with a spacing therebetween. A channel region is interposed between the source and drain regions. A silicon oxide layer serving as an insulation layer is formed on the channel region. A gate terminal is formed on the silicon oxide layer. High-concentration p-type regions are formed in the p-type semiconductor substrate under the source and drain regions, respectively.
    Type: Grant
    Filed: January 6, 1998
    Date of Patent: April 18, 2000
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Naoyuki Shigyo, Toshiyuki Enda
  • Patent number: 5889687
    Abstract: The present invention provides a device simulation method comprising at least the steps of: inputting a geometry of a semiconductor device, a donor and an acceptor impurity concentrations at each point inside the semiconductor device and also terminal voltages of the semiconductor device (step S101); setting initial values by obtaining electron concentrations n, and n.sub.J and also hole concentrations p.sub.I and p.sub.J with respect to given points I and J respectively inside the semiconductor device and also a potential at each point (step S102); obtaining a voltage difference .PSI..sub.dd across a prescribed segment dd along a segment IJ connecting the points I and J (step S103); calculating an electron current density J.sub.eIJ of the segment IJ by an equation J.sub.eLJ =C.sub.eI .multidot.A(.PHI..sub.edd)-C.sub.eJ .multidot.A(-.PHI..sub.edd) using a constant C.sub.eI dependent on the electron concentration n.sub.J, a constant C.sub.eJ dependent on the electron concentration n.sub.
    Type: Grant
    Filed: April 17, 1998
    Date of Patent: March 30, 1999
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Toshiyuki Enda
  • Patent number: 5760442
    Abstract: A first silicon oxide layer serving as an insulation layer is formed on a p-type semiconductor substrate. An n.sup.+ -type source and drain regions are formed on the p-type substrate 110 with a spacing therebetween. A channel region is interposed between the source and drain regions. A second silicon oxide layer serving as a gate insulation layer is formed on the channel region. A gate terminal is formed on the second silicon oxide layer. High-concentration p-type regions are formed in the p-type semiconductor substrate under the source and drain regions, respectively.
    Type: Grant
    Filed: September 29, 1995
    Date of Patent: June 2, 1998
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Naoyuki Shigyo, Toshiyuki Enda