Patents by Inventor Norifumi Kameshiro

Norifumi Kameshiro 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: 8890278
    Abstract: Reliability of a semiconductor device is improved by suppressing reverse voltage deterioration at the time of reverse bias junction barrier Schottky diode using a substrate containing SiC. In a JBS diode having an active area of 0.1 cm2 or more, an area of a Schottky interface at which a drift layer and a Schottky electrode are contacted can be sufficiently reduced by relatively increasing a ratio of p-type semiconductor region being a junction barrier region in an active region, and thereby deterioration in reverse voltage caused by defects existing in the drift layer is prevented.
    Type: Grant
    Filed: October 25, 2012
    Date of Patent: November 18, 2014
    Assignee: Hitachi, Ltd.
    Inventors: Norifumi Kameshiro, Natsuki Yokoyama
  • Publication number: 20130285071
    Abstract: On a front surface of a region where a junction termination extension structure of a semiconductor device using silicon carbide is formed, a structure having an n-type semiconductor region with a concentration relatively higher than a concentration of an n?-type drift layer is formed. An edge of the junction termination extension structure located on a side away from an active region is surrounded from its bottom surface to its front surface by an n-type semiconductor region. By this means, it is possible to provide a device with a low resistance while ensuring a withstand voltage, or by decreasing the resistance of the device, it is possible to provide a device with low power loss.
    Type: Application
    Filed: November 8, 2010
    Publication date: October 31, 2013
    Inventors: Norifumi Kameshiro, Haruka Shimizu
  • Publication number: 20130140584
    Abstract: Disclosed is a JBS diode wherein an increase in an on-voltage is suppressed by sufficiently spreading a current to the lower portion of a junction barrier (p+) region. The JBS diode has a structure, which has an n region having a relatively high concentration compared with the n? drift layer concentration, said n region being in the lower portion of the junction barrier (p+) region.
    Type: Application
    Filed: June 2, 2010
    Publication date: June 6, 2013
    Inventors: Norifumi Kameshiro, Natsuki Yokoyama
  • Patent number: 8106449
    Abstract: To achieve a stable reading operation in a memory cell having a gain-cell structure, a write transistor is configured, which has a source and a drain that are formed on the insulating layer, a channel formed on the insulating layer and between the source and the drain and made of a semiconductor, and a gate formed on an upper portion of the insulating layer and between the source and the drain and electrically insulated from the channel by a gate insulating film and controlling the potential of the channel. The channel electrically connects the source and the drain on the side surfaces of the source and the drain.
    Type: Grant
    Filed: July 27, 2006
    Date of Patent: January 31, 2012
    Assignee: Renesas Electronics Corporation
    Inventors: Toshiaki Sano, Tomoyuki Ishii, Norifumi Kameshiro, Toshiyuki Mine
  • Patent number: 7859889
    Abstract: In a two-transistor gain cell structure, a semiconductor memory device capable of stable reading without malfunction and having small-area memory cells is provided. In a two-transistor gain cell memory having a write transistor and a read transistor, a write word line, a read word line, a write bit line, and a read bit line are separately provided, and voltages to be applied are independently set. Furthermore, a memory cell is connected to the same read word line and write bit line as those of an adjacent memory cell.
    Type: Grant
    Filed: August 5, 2008
    Date of Patent: December 28, 2010
    Assignee: Renesas Electronics Corporation
    Inventors: Norifumi Kameshiro, Riichiro Takemura, Tomoyuki Ishii
  • Patent number: 7772053
    Abstract: After forming a source-drain material film on an insulator layer, an opening portion reaching the insulator layer is formed in the source-drain material film. Then, a channel having desired thickness and a gate insulator are sequentially formed on the insulator layer and the source-drain material film in the opening portion. Thereafter, a gate material film embedding the opening portion is formed on the gate insulator. Subsequently, a cap film is formed on the gate material film, thereby forming the gate made of the gate material film. Then, a mask layer is formed on the source-drain material film. Next, the source-drain material film not protected by the mask layer is removed while protecting the gate by the cap film, thereby leaving the source-drain material film on both sides of the gate. The source-drain material film on one side becomes the source and that on the other side becomes the drain.
    Type: Grant
    Filed: December 14, 2007
    Date of Patent: August 10, 2010
    Assignee: Renesas Technology Corp.
    Inventors: Norifumi Kameshiro, Toshiyuki Mine, Tomoyuki Ishii, Toshiaki Sano
  • Patent number: 7468901
    Abstract: In a two-transistor gain cell structure, a semiconductor memory device capable of stable reading without malfunction and having small-area memory cells is provided. In a two-transistor gain cell memory having a write transistor and a read transistor, a write word line, a read word line, a write bit line, and a read bit line are separately provided, and voltages to be applied are independently set. Furthermore, a memory cell is connected to the same read word line and write bit line as those of an adjacent memory cell.
    Type: Grant
    Filed: April 7, 2006
    Date of Patent: December 23, 2008
    Assignee: Renesas Technology Corp.
    Inventors: Norifumi Kameshiro, Riichiro Takemura, Tomoyuki Ishii
  • Publication number: 20080285325
    Abstract: In a two-transistor gain cell structure, a semiconductor memory device capable of stable reading without malfunction and having small-area memory cells is provided. In a two-transistor gain cell memory having a write transistor and a read transistor, a write word line, a read word line, a write bit line, and a read bit line are separately provided, and voltages to be applied are independently set. Furthermore, a memory cell is connected to the same read word line and write bit line as those of an adjacent memory cell.
    Type: Application
    Filed: August 5, 2008
    Publication date: November 20, 2008
    Inventors: NORIFUMI KAMESHIRO, Riichiro Takemura, Tomoyuki Ishii
  • Publication number: 20080261357
    Abstract: After forming a source-drain material film on an insulator layer, an opening portion reaching the insulator layer is formed in the source-drain material film. Then, a channel having desired thickness and a gate insulator are sequentially formed on the insulator layer and the source-drain material film in the opening portion. Thereafter, a gate material film embedding the opening portion is formed on the gate insulator. Subsequently, a cap film is formed on the gate material film, thereby forming the gate made of the gate material film. Then, a mask layer is formed on the source-drain material film. Next, the source-drain material film not protected by the mask layer is removed while protecting the gate by the cap film, thereby leaving the source-drain material film on both sides of the gate. The source-drain material film on one side becomes the source and that on the other side becomes the drain.
    Type: Application
    Filed: December 14, 2007
    Publication date: October 23, 2008
    Inventors: Norifumi KAMESHIRO, Toshiyuki Mine, Tomoyuki Ishii, Toshiaki Sano
  • Patent number: 7375399
    Abstract: The present invention is a semiconductor memory device having a logic block and a memory block on the same chip. In the memory device, unit memory cells each include at least two transistors, one of which is a write transistor for storing an electric charge into and releasing it from an electric charge storage node, and the other is a read transistor whose conductance in a channel region provided between a source and drain of the read transistor is modulated dependently on the amount of electric charge stored into or released from the electric charge storage node by the write transistor. The read transistor has a gate-insulating film thicker than that of a transistor provided in the logic block, and uses the same diffusion layer structure as that of the logic block.
    Type: Grant
    Filed: June 21, 2005
    Date of Patent: May 20, 2008
    Assignee: Renesas Technology Corp.
    Inventors: Tomoyuki Ishii, Toshiyuki Mine, Toshiaki Sano, Norifumi Kameshiro
  • Publication number: 20070063287
    Abstract: To achieve a stable reading operation in a memory cell having a gain-cell structure, a write transistor is configured, which has a source and a drain that are formed on the insulating layer, a channel formed on the insulating layer and between the source and the drain and made of a semiconductor, and a gate formed on an upper portion of the insulating layer and between the source and the drain and electrically insulated from the channel by a gate insulating film and controlling the potential of the channel. The channel electrically connects the source and the drain on the side surfaces of the source and the drain.
    Type: Application
    Filed: July 27, 2006
    Publication date: March 22, 2007
    Inventors: Toshiaki Sano, Tomoyuki Ishii, Norifumi Kameshiro, Toshiyuki Mine
  • Publication number: 20060227648
    Abstract: In a two-transistor gain cell structure, a semiconductor memory device capable of stable reading without malfunction and having small-area memory cells is provided. In a two-transistor gain cell memory having a write transistor and a read transistor, a write word line, a read word line, a write bit line, and a read bit line are separately provided, and voltages to be applied are independently set. Furthermore, a memory cell is connected to the same read word line and write bit line as those of an adjacent memory cell.
    Type: Application
    Filed: April 7, 2006
    Publication date: October 12, 2006
    Inventors: Norifumi Kameshiro, Riichiro Takemura, Tomoyuki Ishii
  • Publication number: 20050280000
    Abstract: The present invention is a semiconductor memory device having a logic block and a memory block on the same chip. In the memory device, unit memory cells each include at least two transistors, one of which is a write transistor for storing an electric charge into and releasing it from an electric charge storage node, and the other is a read transistor whose conductance in a channel region provided between a source and drain of the read transistor is modulated dependently on the amount of electric charge stored into or released from the electric charge storage node by the write transistor. The read transistor has a gate-insulating film thicker than that of a transistor provided in the logic block, and uses the same diffusion layer structure as that of the logic block.
    Type: Application
    Filed: June 21, 2005
    Publication date: December 22, 2005
    Inventors: Tomoyuki Ishii, Toshiyuki Mine, Toshiaki Sano, Norifumi Kameshiro
  • Patent number: 6888867
    Abstract: A semiconductor laser device includes a substrate and an n-GaN layer composed of a nitride semiconductor formed on the substrate. The substrate includes a trench having as a slope a plane inclined 62 degrees from the main plane of the substrate, or a plane inclined within 3 degrees in an arbitrary direction from the inclined plane. The n-GaN layer is formed on the slope. On the n-GaN layer are formed a lower clad layer, an active layer, and an upper clad layer, each composed of a nitride semiconductor. The active layer has a plane orientation substantially matching the plane orientation of the main plane.
    Type: Grant
    Filed: March 26, 2002
    Date of Patent: May 3, 2005
    Assignees: Sharp Kabushiki Kaisha
    Inventors: Nobuhiko Sawaki, Yoshio Honda, Norifumi Kameshiro, Masahito Yamaguchi, Norikatsu Koide, Shigetoshi Ito, Tomoki Ono, Katsuki Furukawa
  • Publication number: 20030031219
    Abstract: A semiconductor laser device includes a substrate and an n-GaN layer composed of a nitride semiconductor formed on the substrate. The substrate includes a trench having as a slope a plane inclined 62 degrees from the main plane of the substrate, or a plane inclined within 3 degrees in an arbitrary direction from the inclined plane. The n-GaN layer is formed on the slope. On the n-GaN layer are formed a lower clad layer, an active layer, and an upper clad layer, each composed of a nitride semiconductor. The active layer has a plane orientation substantially matching the plane orientation of the main plane.
    Type: Application
    Filed: March 26, 2002
    Publication date: February 13, 2003
    Inventors: Nobuhiko Sawaki, Yoshio Honda, Norifumi Kameshiro, Masahito Yamaguchi, Norikatsu Koide, Shigetoshi Ito, Tomoki Ono, Katsuki Furukawa