Patents by Inventor Yasushi Oka

Yasushi Oka 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: 20090154253
    Abstract: Provided is a nonvolatile memory with less element deterioration and good data retaining properties. In a nonvolatile memory formed by the manufacturing steps of a complementary type MISFET without adding thereto another additional step, erasing of data is carried out by applying 9V to an n type well, 9V to a p type semiconductor region, and ?9V to another p type semiconductor region and setting the source and drain of data writing and erasing MISFETs and data reading MISFETs at open potential to emit electrons from a gate electrode to a p well by FN tunneling. At this time, by applying a negative voltage to the p well having a capacitive element formed thereover and applying a positive voltage to the p well having the MISFETs formed thereover, a potential difference necessary for data erasing operation can be secured at a voltage low enough not to cause gate breakage.
    Type: Application
    Filed: November 13, 2008
    Publication date: June 18, 2009
    Inventors: Kazuyoshi SHIBA, Yasuhiro Taniguchi, Yasushi Oka
  • Publication number: 20090080257
    Abstract: The chip area of a semiconductor device including a nonvolatile memory is reduced. The semiconductor device includes a first memory cell and a second memory cell which are formed on the principal surface of a substrate, and arranged adjacent to each other. In a principal surface of the substrate, active regions which are electrically isolated from each other are arranged. In the first active region, the capacitor element of the first memory cell is arranged, while the capacitor element of the second memory cell is arranged in the fourth active region. In the second active region, the respective write/erase elements of the first and second memory cells are both arranged. Further, in the third active region, the respective read elements of the first and second memory cells are both arranged.
    Type: Application
    Filed: September 18, 2008
    Publication date: March 26, 2009
    Inventors: YASUSHI OKA, Tadashi Omae, Takesada Akiba
  • Publication number: 20090059677
    Abstract: In a data program/erase device of a nonvolatile memory cell, data are re-written by means of an FN tunnel current of an entire channel surface. In a buried n-well of a semiconductor substrate in a flash memory formation region, p wells are placed in the form isolated from each other. In each of the p wells, a capacitor portion, a capacitor portion for programming/erasing data and an MIS•FET for reading data are placed. In the capacitor portion for programming/erasing data, rewriting (programming and erasing) of data is performed by means of an FN tunnel current of an entire channel surface.
    Type: Application
    Filed: October 29, 2008
    Publication date: March 5, 2009
    Inventors: YASUSHI OKA, Kazuyoshi Shiba
  • Patent number: 7466599
    Abstract: Provided is a nonvolatile memory with less element deterioration and good data retaining properties. In a nonvolatile memory formed by the manufacturing steps of a complementary type MISFET without adding thereto another additional step, erasing of data is carried out by applying 9V to an n type well, 9V to a p type semiconductor region, and ?9V to another p type semiconductor region and setting the source and drain of data writing and erasing MISFETs and data reading MISFETs at open potential to emit electrons from a gate electrode to a p well by FN tunneling. At this time, by applying a negative voltage to the p well having a capacitive element formed thereover and applying a positive voltage to the p well having the MISFETs formed thereover, a potential difference necessary for data erasing operation can be secured at a voltage low enough not to cause gate breakage.
    Type: Grant
    Filed: October 26, 2007
    Date of Patent: December 16, 2008
    Assignee: Renesas Technology Corp.
    Inventors: Kazuyoshi Shiba, Yasuhiro Taniguchi, Yasushi Oka
  • Patent number: 7460396
    Abstract: In a data program/erase device of a nonvolatile memory cell, data are re-written by means of an FN tunnel current of an entire channel surface. In a buried n-well of a semiconductor substrate in a flash memory formation region, p wells are placed in the form isolated from each other. In each of the p wells, a capacitor portion, a capacitor portion for programming/erasing data and an MIS•FET for reading data are placed. In the capacitor portion for programming/erasing data, rewriting (programming and erasing) of data is performed by means of an FN tunnel current of an entire channel surface.
    Type: Grant
    Filed: September 7, 2006
    Date of Patent: December 2, 2008
    Assignee: Renesas Technology Corp.
    Inventors: Yasushi Oka, Kazuyoshi Shiba
  • Publication number: 20080259682
    Abstract: A semiconductor device includes a circuit forming area and a memory area including memory cells, first and second wells, a first conductor film formed over both wells and a second conductor film formed over the first well. First semiconductor regions are formed in the first region and a second semiconductor region is formed in the second region. The memory cells each include a capacitance element, including the first conductor film and second region, an element for reading data, including the first conductor film and first regions, and a selection field effect transistor, including the second conductor film and first regions. A length of the first conductor film of the capacitance element is larger than a length of the first conductor film of the element for reading data. A word line of the memory cell is connected to the second semiconductor region.
    Type: Application
    Filed: January 9, 2008
    Publication date: October 23, 2008
    Inventors: Kazuyoshi Shiba, Yasushi Oka
  • Publication number: 20080211001
    Abstract: Provided is a semiconductor device having, over the main surface of a semiconductor substrate, a main circuit region and a memory cell array of a flash memory. The memory cell array has a floating gate electrode for accumulating charges of data, while the main circuit region has a gate electrode of MIS•FET constituting the main circuit. In the main circuit region, an insulating film made of a silicon nitride film is formed to cover the gate electrode, whereby miniaturization of elements in the main circuit region is not impaired. The memory cell array has no such insulating film. This means that the upper surface of the floating gate electrode is not contiguous to the insulating film but is covered directly with an interlayer insulating film. According to such a constitution, leakage of electrons from the floating gate electrode of the memory cell array can be suppressed or prevented and the flash memory thus obtained has improved data retention characteristics.
    Type: Application
    Filed: January 13, 2008
    Publication date: September 4, 2008
    Inventors: Kazuyoshi Shiba, Hideyuki Yashima, Yasushi Oka
  • Patent number: 7388777
    Abstract: A plurality of nonvolatile memory cells that constitute a nonvolatile memory are disposed in array form. Selection MIS•FETs for memory cell selection are electrically connected every bits. Each of the nonvolatile memory cells has a MIS•FET for writing data, a MIS•FET for reading data, and a capacitance section. Gate electrodes of the MIS•FETs and a capacitance electrode of the capacitance section are constituted of part of the same floating gate electrode. A control gate electrode of the nonvolatile memory cell is formed of part of an n well to which the capacitance electrode is opposite.
    Type: Grant
    Filed: January 11, 2006
    Date of Patent: June 17, 2008
    Assignee: Renesas Technology Corp.
    Inventors: Kazuyoshi Shiba, Yasushi Oka
  • Publication number: 20080056011
    Abstract: Provided is a nonvolatile memory with less element deterioration and good data retaining properties. In a nonvolatile memory formed by the manufacturing steps of a complementary type MISFET without adding thereto another additional step, erasing of data is carried out by applying 9V to an n type well, 9V to a p type semiconductor region, and ?9V to another p type semiconductor region and setting the source and drain of data writing and erasing MISFETs and data reading MISFETs at open potential to emit electrons from a gate electrode to a p well by FN tunneling. At this time, by applying a negative voltage to the p well having a capacitive element formed thereover and applying a positive voltage to the p well having the MISFETs formed thereover, a potential difference necessary for data erasing operation can be secured at a voltage low enough not to cause gate breakage.
    Type: Application
    Filed: October 26, 2007
    Publication date: March 6, 2008
    Inventors: Kazuyoshi Shiba, Yasuhiro Taniguchi, Yasushi Oka
  • Publication number: 20070296020
    Abstract: p-type wells are provided within an n-type embedded well of a semiconductor substrate lying in an area for forming a flash memory, in a state of being isolated from one another. A capacitance section, a data write/erase charge injection/discharge section and a data read MIS•FET are disposed in each of the p-type wells. The capacitance section is disposed between the data write/erase charge injection/discharge section and the data read MIS•FET. In the data write/erase charge injection/discharge section, writing and erasing of data by an FN tunnel current at a channel entire surface are performed.
    Type: Application
    Filed: May 2, 2007
    Publication date: December 27, 2007
    Inventors: Kazuyoshi SHIBA, Yasushi Oka
  • Patent number: 7313026
    Abstract: Provided is a nonvolatile memory with less element deterioration and good data retaining properties. In a nonvolatile memory formed by the manufacturing steps of a complementary type MISFET without adding thereto another additional step, erasing of data is carried out by applying 9V to an n type well, 9V to a p type semiconductor region, and ?9V to another p type semiconductor region and setting the source and drain of data writing and erasing MISFETs and data reading MISFETs at open potential to emit electrons from a gate electrode to a p well by FN tunneling. At this time, by applying a negative voltage to the p well having a capacitive element formed thereover and applying a positive voltage to the p well having the MISFETs formed thereover, a potential difference necessary for data erasing operation can be secured at a voltage low enough not to cause gate breakage.
    Type: Grant
    Filed: August 19, 2005
    Date of Patent: December 25, 2007
    Assignee: Renesas Technology Corp.
    Inventors: Kazuyoshi Shiba, Yasuhiro Taniguchi, Yasushi Oka
  • Publication number: 20070058441
    Abstract: In a data program/erase device of a nonvolatile memory cell, data are re-written by means of an FN tunnel current of an entire channel surface. In a buried n-well of a semiconductor substrate in a flash memory formation region, p wells are placed in the form isolated from each other. In each of the p wells, a capacitor portion, a capacitor portion for programming/erasing data and an MIS•FET for reading data are placed. In the capacitor portion for programming/erasing data, rewriting (programming and erasing) of data is performed by means of an FN tunnel current of an entire channel surface.
    Type: Application
    Filed: September 7, 2006
    Publication date: March 15, 2007
    Inventors: Yasushi Oka, Kazuyoshi Shiba
  • Publication number: 20060170035
    Abstract: A plurality of nonvolatile memory cells that constitute a nonvolatile memory are disposed in array form. Selection MIS•FETs for memory cell selection are electrically connected every bits. Each of the nonvolatile memory cells has a MIS•FET for writing data, a MIS•FET for reading data, and a capacitance section. Gate electrodes of the MIS•FETs and a capacitance electrode of the capacitance section are constituted of part of the same floating gate electrode. A control gate electrode of the nonvolatile memory cell is formed of part of an n well to which the capacitance electrode is opposite.
    Type: Application
    Filed: January 11, 2006
    Publication date: August 3, 2006
    Inventors: Kazuyoshi Shiba, Yasushi Oka
  • Publication number: 20060050566
    Abstract: Provided is a nonvolatile memory with less element deterioration and good data retaining properties. In a nonvolatile memory formed by the manufacturing steps of a complementary type MISFET without adding thereto another additional step, erasing of data is carried out by applying 9V to an n type well, 9V to a p type semiconductor region, and ?9V to another p type semiconductor region and setting the source and drain of data writing and erasing MISFETs and data reading MISFETs at open potential to emit electrons from a gate electrode to a p well by FN tunneling. At this time, by applying a negative voltage to the p well having a capacitive element formed thereover and applying a positive voltage to the p well having the MISFETs formed thereover, a potential difference necessary for data erasing operation can be secured at a voltage low enough not to cause gate breakage.
    Type: Application
    Filed: August 19, 2005
    Publication date: March 9, 2006
    Inventors: Kazuyoshi Shiba, Yasuhiro Taniguchi, Yasushi Oka
  • Patent number: 6914832
    Abstract: A semiconductor memory device includes a plurality of blocks, each of which includes a memory cell array, and outputs data signals and a redundancy signal. The semiconductor memory device further includes at least one first multiplexer which is coupled to the blocks, and selects one of the blocks, and a second multiplexer which performs redundancy processing based on the data signals and the redundancy signal which have undergone block selection by the first multiplexer.
    Type: Grant
    Filed: September 2, 2003
    Date of Patent: July 5, 2005
    Assignee: Fujitsu Limited
    Inventors: Andy Cheung, Yasushi Oka
  • Patent number: 6760271
    Abstract: A semiconductor memory device includes a plurality of input/output terminals, a memory cell array which are divided into blocks respectively corresponding to the input/output terminals such that only one of the blocks corresponds to a given one of the input/output terminals, sense amplifiers, which are connected to the blocks at a side thereof, and amplify data of the memory cell array, switches which are respectively connected to the sense amplifiers, and signal lines, which connect the sense amplifiers to a corresponding one of the input/output terminals via the switches.
    Type: Grant
    Filed: March 19, 2001
    Date of Patent: July 6, 2004
    Assignee: Fujitsu Limited
    Inventors: Harunobu Nakagawa, Yasushi Oka
  • Publication number: 20040085799
    Abstract: A semiconductor memory device includes a plurality of blocks, each of which includes a memory cell array, and outputs data signals and a redundancy signal. The semiconductor memory device further includes at least one first multiplexer which is coupled to the blocks, and selects one of the blocks, and a second multiplexer which performs redundancy processing based on the data signals and the redundancy signal which have undergone block selection by the first multiplexer.
    Type: Application
    Filed: September 2, 2003
    Publication date: May 6, 2004
    Inventors: Andy Cheung, Yasushi Oka
  • Publication number: 20020024870
    Abstract: A semiconductor memory device includes a plurality of input/output terminals, a memory cell array which are divided into blocks respectively corresponding to the input/output terminals such that only one of the blocks corresponds to a given one of the input/output terminals, sense amplifiers, which are connected to the blocks at a side thereof, and amplify data of the memory cell array, switches which are respectively connected to the sense amplifiers, and signal lines, which connect the sense amplifiers to a corresponding one of the input/output terminals via the switches.
    Type: Application
    Filed: March 19, 2001
    Publication date: February 28, 2002
    Applicant: FUJITSU LIMITED
    Inventors: Harunobu Nakagawa, Yasushi Oka