Patents by Inventor Digh Hisamoto

Digh Hisamoto 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: 8410543
    Abstract: In a non-volatile memory in which writing/erasing is performed by changing a total charge amount by injecting electrons and holes into a silicon nitride film serving as a charge accumulation layer, in order to realize a high efficiency of a hole injection from a gate electrode, the gate electrode of a memory cell comprises a laminated structure made of a plurality of polysilicon films with different impurity concentrations, for example, a two-layered structure comprising a p-type polysilicon film with a low impurity concentration and a p+-type polysilicon film with a high impurity concentration deposited thereon.
    Type: Grant
    Filed: December 27, 2007
    Date of Patent: April 2, 2013
    Assignee: Renesas Electronics Corporation
    Inventors: Itaru Yanagi, Toshiyuki Mine, Hirotaka Hamamura, Digh Hisamoto, Yasuhiro Shimamoto
  • Patent number: 8409949
    Abstract: Provided is a nonvolatile semiconductor memory device highly integrated and highly reliable. A plurality of memory cells are formed in a plurality of active regions sectioned by a plurality of isolations (silicon oxide films) extending in the Y direction and deeper than a well (p type semiconductor region). In each memory cell, a contact is provided in the well (p type semiconductor region) so as to penetrate through a source diffusion layer (n+ type semiconductor region), and the contact that electrically connects bit lines (metal wirings) and the source diffusion layer (n+ type semiconductor region) is also electrically connected to the well (p type semiconductor region).
    Type: Grant
    Filed: June 23, 2010
    Date of Patent: April 2, 2013
    Assignee: Renesas Electronics Corporation
    Inventors: Tsuyoshi Arigane, Digh Hisamoto, Yasuhiro Shimamoto, Toshiyuki Mine
  • Patent number: 8385124
    Abstract: The semiconductor device includes the nonvolatile memory cell in the main surface of a semiconductor substrate. The nonvolatile memory cell has a first insulating film over the semiconductor substrate, a conductive film, a second insulating film, the charge storage film capable of storing therein charges, a third insulating film over the charge storage film, a first gate electrode, a fourth insulating film in contact with the set of stacked films from the first insulating film to the foregoing first gate electrode, a fifth insulating film juxtaposed with the first insulating film over the foregoing semiconductor substrate, a second gate electrode formed over the fifth insulating film to be adjacent to the foregoing first gate electrode over the side surface of the fourth insulating film, and source/drain regions with the first and second gate electrodes interposed therebetween. The conductive film and the charge storage film are formed to two-dimensionally overlap.
    Type: Grant
    Filed: March 29, 2011
    Date of Patent: February 26, 2013
    Assignee: Renesas Electronics Corporation
    Inventors: Tsuyoshi Arigane, Digh Hisamoto, Yasuhiro Shimamoto, Yutaka Okuyama
  • Patent number: 8324092
    Abstract: A method of manufacturing a non-volatile semiconductor memory device is provided which overcomes a problem of penetration of implanted ions due to the difference of optimal gate height in simultaneous formation of a self-align split gate type memory cell utilizing a side wall structure and a scaled MOS transistor. A select gate electrode to form a side wall in a memory area is formed to be higher than that of the gate electrode in a logic area so that the height of the side wall gate electrode of the self-align split gate memory cell is greater than that of the gate electrode in the logic area. Height reduction for the gate electrode is performed in the logic area before gate electrode formation.
    Type: Grant
    Filed: January 5, 2010
    Date of Patent: December 4, 2012
    Assignee: Renesas Electronics Corporation
    Inventors: Kan Yasui, Digh Hisamoto, Tetsuya Ishimaru, Shin-Ichiro Kimura
  • Patent number: 8319274
    Abstract: A gate dielectric functioning as a charge-trapping layer of a non-volatile memory cell with a structure of an insulator gate field effect transistor is formed by laminating a first insulator formed of a silicon oxide film, a second insulator formed of a silicon nitride film, a third insulator formed of a silicon nitride film containing oxygen, and a fourth insulator formed of a silicon oxide film in this order on a main surface of a semiconductor substrate. Holes are injected into the charge-trapping layer from a gate electrode side. Accordingly, since the operations can be achieved without the penetration of the holes through the interface in contact to the channel and the first insulator, the deterioration in rewriting endurance and the charge-trapping characteristics due to the deterioration of the first insulator does not occur, and highly efficient rewriting (writing and erasing) characteristics and stable charge-trapping characteristics can be achieved.
    Type: Grant
    Filed: July 27, 2007
    Date of Patent: November 27, 2012
    Assignee: Renesas Electronics Corporation
    Inventors: Digh Hisamoto, Itaru Yanagi, Yasuhiro Shimamoto, Toshiyuki Mine, Yutaka Okuyama
  • Patent number: 8319265
    Abstract: A semiconductor memory array includes a first nonvolatile memory cell having a first charge storage layer and a first gate electrode and a second nonvolatile memory cell, adjacent to the first memory cell in a first direction, having a second charge storage layer and a second gate electrode. The first and second electrodes extend in a second direction perpendicular to the first direction, the first electrode has a first contact section extending toward the second electrode in the first direction, and the second electrode has a second contact section extending toward the first electrode in the first direction. The first and second contact positions are shifted in the second direction, respectively, and the first electrode and the first contact section are electrically separated from the second electrode and the second contact section.
    Type: Grant
    Filed: October 16, 2009
    Date of Patent: November 27, 2012
    Assignee: Renesas Electronics Corporation
    Inventors: Tsutomu Okazaki, Daisuke Okada, Kyoya Nitta, Toshihiro Tanaka, Akira Kato, Toshikazu Matsui, Yasushi Ishii, Digh Hisamoto, Kan Yasui
  • Publication number: 20120287959
    Abstract: A germanium light-emitting device emitting light at high efficiency is provided by using germanium of small threading dislocation density. A germanium laser diode having a high quality germanium light-emitting layer is attained by using germanium formed over silicon dioxide. A germanium laser diode having a carrier density higher than the carrier density limit that can be injected by existent n-type germanium can be provided using silicon as an n-type electrode.
    Type: Application
    Filed: January 28, 2011
    Publication date: November 15, 2012
    Inventors: Kazuki Tani, Shinichi Saito, Toshiki Sugawara, Youngkun Lee, Digh Hisamoto, Makoto Miura, Katsuya Oda
  • Publication number: 20120217513
    Abstract: A SiC MOSFET has a subject that resistance in the source region is increased when annealing for metal silicidation is performed to a source region before forming the gate insulating film, the metal silicide layer of the source region is oxidized by an oxidizing treatment (including oxynitriding treatment) when the gate insulating film is formed. When a metal silicide layer to be formed on the surface of a SiC epitaxial substrate is formed before forming a gate insulating film interface layer (oxide film), and an anti-oxidation film for the metal silicide is formed on the metal silicide layer, it is possible to suppress oxidation of the metal silicide layer by the oxidizing treatment upon forming the gate insulating film interface layer and the resistance of the source region can be decreased without lowering the channel mobility.
    Type: Application
    Filed: January 12, 2012
    Publication date: August 30, 2012
    Inventors: Naoki TEGA, Yasuhiro Shimamoto, Yuki Mori, Hirotaka Hamamura, Hiroyuki Okino, Digh Hisamoto
  • Patent number: 8193053
    Abstract: An object of the present invention is to provide an integrated semiconductor nonvolatile storage device that can be read at high speed and reprogrammed an increased number of times. In the case of conventional nonvolatile semiconductor storage devices having a split-gate structure, there is a tradeoff between the read current and the maximum allowable number of reprogramming operations. To overcome this problem, an integrated semiconductor nonvolatile storage device of the present invention is configured such that memory cells having different memory gate lengths are integrated on the same chip. This allows the device to be read at high speed and reprogrammed an increased number of times.
    Type: Grant
    Filed: April 20, 2010
    Date of Patent: June 5, 2012
    Assignee: Renesas Electronics Corporation
    Inventors: Digh Hisamoto, Shin'ichiro Kimura, Daiske Okada, Kan Yasui
  • Publication number: 20120086070
    Abstract: A non-volatile semiconductor memory device with good write/erase characteristics is provided. A selection gate is formed on a p-type well of a semiconductor substrate via a gate insulator, and a memory gate is formed on the p-type well via a laminated film composed of a silicon oxide film, a silicon nitride film, and a silicon oxide film. The memory gate is adjacent to the selection gate via the laminated film. In the regions on both sides of the selection gate and the memory gate in the p-type well, n-type impurity diffusion layers serving as the source and drain are formed. The region controlled by the selection gate and the region controlled by the memory gate located in the channel region between said impurity diffusion layers have the different charge densities of the impurity from each other.
    Type: Application
    Filed: December 16, 2011
    Publication date: April 12, 2012
    Inventors: Digh HISAMOTO, Shinichiro KIMURA, Kan YASUI, Nozomu MATSUZAKI
  • Publication number: 20120026798
    Abstract: An operation scheme for operating stably a semiconductor nonvolatile memory device is provided. When hot-hole injection is conducted in the semiconductor nonvolatile memory device of a split gate structure, the hot-hole injection is verified using a crossing point that does not change with time. Thus, an erased state can be verified without being aware of any time-varying changes. Also, programming or programming/erasure is conducted by repeating pulse voltage or multi-step voltage application to a gate section multiple times.
    Type: Application
    Filed: October 7, 2011
    Publication date: February 2, 2012
    Inventors: Digh HISAMOTO, Kan Yasui, Tetsuya Ishimaru, Shinichiro Kimura, Daisuke Okada
  • Patent number: 8084810
    Abstract: A non-volatile semiconductor memory device with good write/erase characteristics is provided. A selection gate is formed on a p-type well of a semiconductor substrate via a gate insulator, and a memory gate is formed on the p-type well via a laminated film composed of a silicon oxide film, a silicon nitride film, and a silicon oxide film. The memory gate is adjacent to the selection gate via the laminated film. In the regions on both sides of the selection gate and the memory gate in the p-type well, n-type impurity diffusion layers serving as the source and drain are formed. The region controlled by the selection gate and the region controlled by the memory gate located in the channel region between said impurity diffusion layers have the different charge densities of the impurity from each other.
    Type: Grant
    Filed: December 29, 2009
    Date of Patent: December 27, 2011
    Assignee: Renesas Electronics Corporation
    Inventors: Digh Hisamoto, Shinichiro Kimura, Kan Yasui, Nozomu Matsuzaki
  • Patent number: 8076709
    Abstract: In a situation where a memory cell includes an ONO film, which comprises a silicon nitride film for charge storage and oxide films positioned above and below the silicon nitride film; a memory gate above the ONO film; a select gate, which is adjacent to a lateral surface of the memory gate via the ONO film; a gate insulator positioned below the select gate; a source region; and a drain region, an erase operation is performed by injecting holes generated by BTBT into the silicon nitride film while applying a positive potential to the source region, applying a negative potential to the memory gate, applying a positive potential to the select gate, and flowing a current from the drain region to the source region, thus improving the characteristics of a nonvolatile semiconductor memory device.
    Type: Grant
    Filed: September 1, 2010
    Date of Patent: December 13, 2011
    Assignee: Renesas Electronics Corporation
    Inventors: Tetsuya Ishimaru, Digh Hisamoto, Kan Yasui, Shinichiro Kimura
  • Patent number: 8064261
    Abstract: An operation scheme for operating stably a semiconductor nonvolatile memory device is provided. When hot-hole injection is conducted in the semiconductor nonvolatile memory device of a split gate structure, the hot-hole injection is verified using a crossing point that does not change with time. Thus, an erased state can be verified without being aware of any time-varying changes. Also, programming or programming/erasure is conducted by repeating pulse voltage or multi-step voltage application to a gate section multiple times.
    Type: Grant
    Filed: May 25, 2010
    Date of Patent: November 22, 2011
    Assignee: Renesas Electronics Corporation
    Inventors: Digh Hisamoto, Kan Yasui, Tetsuya Ishimaru, Shinichiro Kimura, Daisuke Okada
  • Publication number: 20110242888
    Abstract: The semiconductor device includes the nonvolatile memory cell in the main surface of a semiconductor substrate. The nonvolatile memory cell has a first insulating film over the semiconductor substrate, a conductive film, a second insulating film, the charge storage film capable of storing therein charges, a third insulating film over the charge storage film, a first gate electrode, a fourth insulating film in contact with the set of stacked films from the first insulating film to the foregoing first gate electrode, a fifth insulating film juxtaposed with the first insulating film over the foregoing semiconductor substrate, a second gate electrode formed over the fifth insulating film to be adjacent to the foregoing first gate electrode over the side surface of the fourth insulating film, and source/drain regions with the first and second gate electrodes interposed therebetween. The conductive film and the charge storage film are formed to two-dimensionally overlap.
    Type: Application
    Filed: March 29, 2011
    Publication date: October 6, 2011
    Inventors: Tsuyoshi ARIGANE, Digh Hisamoto, Yasuhiro Shimamoto, Yutaka Okuyama
  • Patent number: 8030668
    Abstract: A light emitting diode demonstrating high luminescence efficiency and comprising a Group IV semiconductor such as silicon or germanium equivalent thereto as a basic component formed on a silicon substrate by a prior art silicon process, and a fabricating method of waveguide thereof are provided. The light emitting diode of the invention comprises a first electrode for implanting electrons, a second electrode for implanting holes, and a light emitting section electrically connected to the first and the second electrode, wherein the light emitting section is made out of single crystalline silicon and has a first surface and a second surface facing the first surface, wherein with respect to plane orientation (100) of the first and second surfaces, the light emitting section crossing at right angles to the first and second surfaces is made thinner, and wherein a material having a high refractive index is arranged around the thin film section.
    Type: Grant
    Filed: November 6, 2007
    Date of Patent: October 4, 2011
    Assignee: Hitachi, Ltd.
    Inventors: Digh Hisamoto, Shinichi Saito, Shinichiro Kimura
  • Patent number: 7935597
    Abstract: Performance and reliability of a semiconductor device including a non-volatile memory are improved. A memory cell of the non-volatile memory includes, over an upper portion of a semiconductor substrate, a select gate electrode formed via a first dielectric film and a memory gate electrode formed via a second dielectric film formed of an ONO multilayered film having a charge storing function. The first dielectric film functions as a gate dielectric film, and includes a third dielectric film made of silicon oxide or silicon oxynitride and a metal-element-containing layer made of a metal oxide or a metal silicate formed between the select gate electrode and the third dielectric film. A semiconductor region positioned under the memory gate electrode and the second dielectric film has a charge density of impurities lower than that of a semiconductor region positioned under the select gate electrode and the first dielectric film.
    Type: Grant
    Filed: October 26, 2010
    Date of Patent: May 3, 2011
    Assignee: Renesas Electronics Corporation
    Inventors: Yasuhiro Shimamoto, Digh Hisamoto, Tetsuya Ishimaru, Shinichiro Kimura
  • Patent number: 7915666
    Abstract: An erase method where a corner portion on which an electric field concentrates locally is provided on the memory gate electrode, and charges in the memory gate electrode are injected into a charge trap film in a gate dielectric with Fowler-Nordheim tunneling operation is used. Since current consumption at the time of erase can be reduced by the Fowler-Nordheim tunneling, a power supply circuit area of a memory module can be reduced. Since write disturb resistance can be improved, a memory array area can be reduced by adopting a simpler memory array configuration. Owing to both the effects, an area of the memory module can be largely reduced, so that manufacturing cost can be reduced. Further, since charge injection centers of write and erase coincide with each other, so that (program and erase) endurance is improved.
    Type: Grant
    Filed: May 20, 2008
    Date of Patent: March 29, 2011
    Assignee: Renesas Electronics Corporation
    Inventors: Kan Yasui, Tetsuya Ishimaru, Digh Hisamoto, Yasuhiro Shimamoto
  • Publication number: 20110039385
    Abstract: Performance and reliability of a semiconductor device including a non-volatile memory are improved. A memory cell of the non-volatile memory includes, over an upper portion of a semiconductor substrate, a select gate electrode formed via a first dielectric film and a memory gate electrode formed via a second dielectric film formed of an ONO multilayered film having a charge storing function. The first dielectric film functions as a gate dielectric film, and includes a third dielectric film made of silicon oxide or silicon oxynitride and a metal-element-containing layer made of a metal oxide or a metal silicate formed between the select gate electrode and the third dielectric film. A semiconductor region positioned under the memory gate electrode and the second dielectric film has a charge density of impurities lower than that of a semiconductor region positioned under the select gate electrode and the first dielectric film.
    Type: Application
    Filed: October 26, 2010
    Publication date: February 17, 2011
    Inventors: Yasuhiro Shimamoto, Digh Hisamoto, Tetsuya Ishimaru, Shinichiro Kimura
  • Patent number: 7890898
    Abstract: Capacity-gate voltage characteristics of a field-effect transistor having plural gates are measured against a voltage change in each one of the gates for an inverted MOSFET and for an accumulated MOSFET, respectively. These measurements together with numerical simulations provided from a model for quantum effects are used to determine flat band voltages between the plural gates and a channel. Next, an effective normal electric field is calculated as a vector line integral by using a set of flat band voltages for the measured capacity as a lower integration limit. Lastly, mobility depending on the effective normal electric field is calculated from current-gate voltage characteristic measurements and capacity measurements in a source-drain path, and the calculated mobility is substituted into an equation for a current-voltage curve between source and drain.
    Type: Grant
    Filed: January 31, 2008
    Date of Patent: February 15, 2011
    Assignee: Hitachi, Ltd.
    Inventors: Hiroyuki Yoshimoto, Nobuyuki Sugii, Shinichi Saito, Digh Hisamoto