Patents by Inventor Makoto Iwai

Makoto Iwai 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: 9287453
    Abstract: In the case that a functional layer, made of a nitride of a group 13 element, is formed on a composite substrate including a sapphire body and a gallium nitride crystal layer disposed over the sapphire body, the deviation of the function is prevented. The composite substrate 4 includes a sapphire body 1A and a gallium nitride crystal layer 3 disposed over the sapphire body. Aa warpage of the composite substrate is in a range of not less than +40 ?m and not more than +80 ?m per 5.08 cm in length.
    Type: Grant
    Filed: September 14, 2015
    Date of Patent: March 15, 2016
    Assignee: NGK INSULATORS, LTD.
    Inventors: Makoto Iwai, Katsuhiro Imai, Masahiro Sakai
  • Publication number: 20160049554
    Abstract: The maximum value of peak intensities of cathode luminescence of a wavelength corresponding to a band gap of gallium nitride and in a measured visual field of 0.1 mm×0.1 mm is 140 percent or higher of an average value of the peak intensities of the cathode luminescence, provided that the peak intensities of the cathode luminescence are measured on a surface of the gallium nitride substrate.
    Type: Application
    Filed: October 27, 2015
    Publication date: February 18, 2016
    Applicant: NGK INSULATORS, LTD.
    Inventors: Makoto Iwai, Masahiro Sakai, Katsuhiro Imai, Yoshitaka Kuraoka
  • Publication number: 20160042801
    Abstract: A memory includes first and second select gate transistors, memory cells, a source line, a bit line, a selected word line which is connected to a selected memory cell as a target of a verify reading, a non-selected word line which is connected to a non-selected memory cell except the selected memory cell, a potential generating circuit for generating a selected read potential which is supplied to the selected word line, and generating a non-selected read potential larger than the selected read potential, which is supplied to the non-selected word line, and a control circuit which classifies a threshold voltage of the selected memory cell to one of three groups by verifying which area among three area which are isolated by two values does a cell current of the selected memory cell belong, when the selected read potential is a first value.
    Type: Application
    Filed: October 19, 2015
    Publication date: February 11, 2016
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Makoto IWAI, Hiroshi NAKAMURA
  • Publication number: 20160005924
    Abstract: In the case that a functional layer, made of a nitride of a group 13 element, is formed on a composite substrate including a sapphire body and a gallium nitride crystal layer disposed over the sapphire body, the deviation of the function is prevented. The composite substrate 4 includes a sapphire body 1A and a gallium nitride crystal layer 3 disposed over the sapphire body. Aa warpage of the composite substrate is in a range of not less than +40 ?m and not more than +80 ?m per 5.08 cm in length.
    Type: Application
    Filed: September 14, 2015
    Publication date: January 7, 2016
    Applicant: NGK INSULATORS, LTD.
    Inventors: Makoto Iwai, Katsuhiro Imai, Masahiro Sakai
  • Patent number: 9231155
    Abstract: A composite substrate 10 includes a sapphire body 1A, a seed crystal film 4 composed of gallium nitride crystal and provided on a surface of the sapphire body, and a gallium nitride crystal layer 7 grown on the seed crystal film 4 and having a thickness of 200 ?m or smaller. Voids 5 are provided along an interface between the sapphire body 1A and the seed crystal film 4 in a void ratio of 4.5 to 12.5 percent.
    Type: Grant
    Filed: December 24, 2013
    Date of Patent: January 5, 2016
    Assignee: NGK INSULATORS, LTD.
    Inventors: Yoshitaka Kuraoka, Makoto Iwai
  • Publication number: 20150303066
    Abstract: In a substrate having a gallium nitride layer, surface damage after surface treatment of the gallium nitride layer is reduced and quality of a functional device formed thereon is improved. A substrate 4 having at least a gallium nitride layer 4 is provided. A plasma etching system equipped with an inductively coupled plasma generating system is used and a fluorine-based gas is introduced at a standardized direct current bias potential of ?10V/cm2 or higher to subject a surface 3a of the gallium nitride layer to dry etching treatment.
    Type: Application
    Filed: June 30, 2015
    Publication date: October 22, 2015
    Applicant: NGK INSULATORS, LTD.
    Inventors: Shuhei Higashihara, Makoto Iwai, Katsuhiro Imai
  • Publication number: 20150287884
    Abstract: A seed crystal substrate 8 includes a base body 1 and a plurality of rows of stripe-shaped seed crystal layers 3 formed on the base body 1. An upper face 3a of the seed crystal layer 3 is (11-22) plane, a groove 4 is formed between the adjacent seed crystal layers 3, and a longitudinal direction of the groove 4 is a direction in which a c-axis of a crystal forming the seed crystal layer is projected on the upper face. A nitride of a group 13 element is formed on the seed crystal substrate.
    Type: Application
    Filed: June 18, 2015
    Publication date: October 8, 2015
    Applicant: NGK INSULATORS, LTD.
    Inventors: Shuuhei Higashihara, Makoto Iwai
  • Patent number: 9090988
    Abstract: It is provided a method of producing a crystal of a nitride of a group 13 element in a melt by flux method. The melt is generated by heating a composition including a material for the group 13 element, a material for at least one of an alkali metal and an alkaline earth metal and a liquid material for germanium. Upon producing a crystal of a nitride of a group 13 element in a melt by flux method, it is thereby possible to reduce in-plane distribution of a property such as carrier density of the thus obtained crystal of a nitride of a group 13 element.
    Type: Grant
    Filed: June 25, 2014
    Date of Patent: July 28, 2015
    Assignee: NGK INSULATORS, LTD.
    Inventors: Masahiro Sakai, Makoto Iwai
  • Publication number: 20150187926
    Abstract: Provided are a group 13 nitride composite substrate allowing for the production of a semiconductor device suitable for high-frequency applications while including a conductive GaN substrate, and a semiconductor device produced using this substrate. The group 13 nitride composite substrate includes a base material of an n-conductivity type formed of GaN, a base layer located on the base material, being a group 13 nitride layer having a resistivity of 1×106 ?·cm or more, a channel layer located on the base layer, being a GaN layer having a total impurity density of 1×1017/cm3 or less, and a barrier layer that is located on the channel layer and is formed of a group 13 nitride having a composition AlxInyGa1-x-yN (0?x?1, 0?y?1).
    Type: Application
    Filed: March 13, 2015
    Publication date: July 2, 2015
    Applicant: NGK INSULATORS, LTD.
    Inventors: Yoshitaka Kuraoka, Mikiya Ichimura, Makoto Iwai
  • Patent number: 9065012
    Abstract: Protrusions 2 each having a shape of a pyramid or a truncated pyramid are regularly arranged on a growing face 1a of a seed crystal 1 composed of gallium nitride single crystal. It is formed a gallium nitride crystal layer 4 having a thickness of 100 ?m or smaller by flux method directly on the growing face 1a of the seed crystal.
    Type: Grant
    Filed: May 28, 2014
    Date of Patent: June 23, 2015
    Assignee: NGK INSULATORS, LTD.
    Inventors: Shuuhei Higashihara, Makoto Iwai
  • Patent number: 9045844
    Abstract: A film 3 of a nitride of a group 13 element is grown on a seed crystal substrate 11 by flux process from a melt containing a flux and the group 13 element under nitrogen containing atmosphere. The film 3 of the nitride of the group 13 element includes an inclusion distributed layer 3a in a region distant from an interface 11a of the film 3 of the nitride of the group 13 element on the side of the seed crystal substrate 11 and containing inclusions derived from components of the melt, and an inclusion depleted layer 3b, with the inclusion depleted. provided on the layer 3a. Laser light A is irradiated from the side of the back face 1b of the seed crystal substrate 11 to peel the single crystal 3 of the nitride of the group 13 element from the seed crystal substrate 11 by laser lift-off method.
    Type: Grant
    Filed: January 29, 2014
    Date of Patent: June 2, 2015
    Assignee: NGK INSULATORS, LTD.
    Inventors: Makoto Iwai, Takayuki Hirao, Takashi Yoshino
  • Patent number: 9041004
    Abstract: A film 3 of a nitride of a group 13 element is grown on a seed crystal substrate 11 by flux process from a melt containing a flux and a group 13 element under nitrogen containing atmosphere. The film 3 of a nitride of a group 13 element includes an inclusion distributed layer 3a in a region distant from an interface of the film of a nitride of group 13 element on the side of the seed crystal substrate 11 and containing inclusions derived from components of the melt, and an inclusion depleted layer 3b, with the inclusion depleted. provided on the layer 3a.
    Type: Grant
    Filed: January 29, 2014
    Date of Patent: May 26, 2015
    Assignee: NGK Insulators, Ltd.
    Inventors: Makoto Iwai, Takayuki Hirao, Takashi Yoshino
  • Patent number: 9030880
    Abstract: According to one embodiment, a nonvolatile semiconductor storage device includes a memory cell array where memory cells are arranged in a cell well in a row direction and a column direction in a matrix; word lines which select the memory cell in the row direction; bit lines which select the memory cell in the column direction; a sense amplifier which determines a value stored in the memory cell based on a potential of the bit line; a peripheral transistor in the memory cell array which is arranged in the periphery of the memory cell array; and an enhancement type transistor which drives a gate of the peripheral transistor.
    Type: Grant
    Filed: March 19, 2013
    Date of Patent: May 12, 2015
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Makoto Iwai
  • Patent number: 9017479
    Abstract: The apparatus has a crucible for storing a solution; an inner container for storing a crucible; a heating container for storing the inner container, the heating container including heating elements, a container body provided with the heating elements and a lid combined with the container body; and a pressure vessel for storing the heating container and for charging an atmosphere comprising at least nitrogen gas. The lid also has a fitting surface to the container body that is inclined to a horizontal plane.
    Type: Grant
    Filed: July 29, 2008
    Date of Patent: April 28, 2015
    Assignees: NGK Insulators, Ltd., Osaka University, Toyoda Gosei Co., Ltd.
    Inventors: Makoto Iwai, Takanao Shimodaira, Takatomo Sasaki, Yusuke Mori, Fumio Kawamura, Shiro Yamasaki
  • Patent number: 8999059
    Abstract: A growth apparatus is used having a plurality of crucibles each for containing the solution, a heating element for heating the crucible, and a pressure vessel for containing at least the crucibles and the heating element and for filling an atmosphere comprising at least nitrogen gas. One seed crystal is put in each of the crucibles to grow the nitride single crystal on the seed crystal.
    Type: Grant
    Filed: September 22, 2008
    Date of Patent: April 7, 2015
    Assignees: NGK Insulators, Ltd., Osaka University
    Inventors: Katsuhiro Imai, Makoto Iwai, Takanao Shimodaira, Takatomo Sasaki, Yusuke Mori, Fumio Kawamura
  • Publication number: 20140305369
    Abstract: It is provided a method of producing a crystal of a nitride of a group 13 element in a melt by flux method. The melt is generated by heating a composition including a material for the group 13 element, a material for at least one of an alkali metal and an alkaline earth metal and a liquid material for germanium. Upon producing a crystal of a nitride of a group 13 element in a melt by flux method, it is thereby possible to reduce in-plane distribution of a property such as carrier density of the thus obtained crystal of a nitride of a group 13 element.
    Type: Application
    Filed: June 25, 2014
    Publication date: October 16, 2014
    Applicant: NGK INSULATORS, LTD.
    Inventors: Masahiro Sakai, Makoto Iwai
  • Patent number: 8848446
    Abstract: A nonvolatile semiconductor memory device includes bit lines, word lines, NAND strings, source lines, first and second select gate transistors, and a controller. After giving a first potential to the second select gate transistors, the controller gives a second potential lower than the first potential to the second select gate transistors, gives a third potential to the memory cells which are insufficient in the writing, gives a fourth potential higher than the third potential to the memory cells which are just before completion of the writing, and gives a fifth potential higher than the fourth potential to the memory cells which are completed in the writing. The first potential is capable of turning on the second select gate transistors. The second potential is capable of turning off the second select gate transistors.
    Type: Grant
    Filed: April 18, 2012
    Date of Patent: September 30, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Makoto Iwai
  • Publication number: 20140264429
    Abstract: Protrusions 2 each having a shape of a pyramid or a truncated pyramid are regularly arranged on a growing face 1a of a seed crystal 1 composed of gallium nitride single crystal. It is formed a gallium nitride crystal layer 4 having a thickness of 100 ?m or smaller by flux method directly on the growing face 1a of the seed crystal.
    Type: Application
    Filed: May 28, 2014
    Publication date: September 18, 2014
    Applicant: NGK INSULATORS, LTD.
    Inventors: Shuuhei Higashihara, Makoto Iwai
  • Publication number: 20140233311
    Abstract: A memory includes first and second select gate transistors, memory cells, a source line, a bit line, a selected word line which is connected to a selected memory cell as a target of a verify reading, a non-selected word line which is connected to a non-selected memory cell except the selected memory cell, a potential generating circuit for generating a selected read potential which is supplied to the selected word line, and generating a non-selected read potential larger than the selected read potential, which is supplied to the non-selected word line, and a control circuit which classifies a threshold voltage of the selected memory cell to one of three groups by verifying which area among three area which are isolated by two values does a cell current of the selected memory cell belong, when the selected read potential is a first value.
    Type: Application
    Filed: April 28, 2014
    Publication date: August 21, 2014
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Makoto IWAI, Hiroshi NAKAMURA
  • Publication number: 20140197420
    Abstract: A film 3 of a nitride of a group 13 element is grown on a seed crystal substrate 11 by flux process from a melt containing a flux and a group 13 element under nitrogen containing atmosphere. The film 3 of a nitride of a group 13 element includes an inclusion distributed layer 3a in a region distant from an interface of the film of a nitride of group 13 element on the side of the seed crystal substrate 11 and containing inclusions derived from components of the melt, and an inclusion depleted layer 3b, with the inclusion depleted. provided on the layer 3a.
    Type: Application
    Filed: January 29, 2014
    Publication date: July 17, 2014
    Applicant: NGK INSULATORS, LTD.
    Inventors: Makoto Iwai, Takayuki Hirao, Takashi Yoshino