Patents by Inventor Tadahiro Imada

Tadahiro Imada 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: 20130334540
    Abstract: A first electrode, an intrinsic first compound semiconductor layer over the first electrode, a second compound semiconductor layer whose band gap is smaller than that of the first compound semiconductor layer on the first compound semiconductor layer, and a second electrode over the second compound semiconductor layer are provided.
    Type: Application
    Filed: August 21, 2013
    Publication date: December 19, 2013
    Applicant: FUJITSU LIMITED
    Inventor: Tadahiro Imada
  • Publication number: 20130256684
    Abstract: An embodiment of a compound semiconductor device includes: a substrate; an electron transport layer formed over the substrate; an electron supply layer formed over the electron transport layer; a source electrode and a drain electrode formed over the electron supply layer; a gate electrode formed over the electron supply layer between the source electrode and the drain electrode; a p-type compound semiconductor layer formed between the electron supply layer and the gate electrode; and a compound semiconductor layer containing an n-type impurity formed between the electron supply layer and the p-type compound semiconductor layer.
    Type: Application
    Filed: December 21, 2012
    Publication date: October 3, 2013
    Inventors: Masato NISHIMORI, Toshihide Kikkawa, Tadahiro Imada
  • Publication number: 20130240953
    Abstract: A semiconductor device, that has a transistor region and a surge-protector region, includes: a substrate; a first semiconductor layer formed on the substrate; a second semiconductor layer formed on the first semiconductor layer; a gate electrode, a source electrode, and a drain electrode formed on the second semiconductor layer in the transistor region; and a surge-protector first electrode, a surge-protector second electrode, and a surge-protector third electrode formed on the second semiconductor layer in the surge-protector region, wherein the source electrode and the surge-protector second electrode are connected to each other, wherein the drain electrode and the surge-protector third electrode are connected to each other, wherein the surge-protector first electrode is formed between the surge-protector second electrode and the surge-protector third electrode, and wherein a distance between the surge-protector first electrode and the surge-protector third electrode is smaller than a distance between the g
    Type: Application
    Filed: February 28, 2013
    Publication date: September 19, 2013
    Applicant: FUJITSU LIMITED
    Inventor: Tadahiro IMADA
  • Publication number: 20130240897
    Abstract: A semiconductor device includes a first semiconductor layer formed over a substrate; a second semiconductor layer formed over the first semiconductor layer; electrodes formed over the second semiconductor layer; and a third semiconductor layer formed on the second semiconductor layer; wherein the third semiconductor layer is formed so as to surround each element, in which the electrodes are formed, and wherein the third semiconductor layer is a semiconductor layer of a conductivity type whose polarity is opposite to that of carriers produced in the first semiconductor layer.
    Type: Application
    Filed: February 4, 2013
    Publication date: September 19, 2013
    Applicant: FUJITSU LIMITED
    Inventor: Tadahiro IMADA
  • Publication number: 20130233489
    Abstract: A wet etching method that includes forming an insulating film on a substrate, and irradiating laser light to the insulating film during wet etching of the insulating film using an etching solution.
    Type: Application
    Filed: April 30, 2013
    Publication date: September 12, 2013
    Applicant: FUJITSU LIMITED
    Inventors: Tadahiro Imada, Yoshihiro Nakata, Koji Nozaki
  • Publication number: 20130228795
    Abstract: A semiconductor device includes a first semiconductor layer of a first conductivity type formed on one side of a semiconductor substrate; a second semiconductor layer of a second conductivity type formed on the first semiconductor layer; a third semiconductor layer of the first conductivity type formed on the second semiconductor layer; an opening part formed by removing part of the first to third semiconductor layers; a gate insulating film formed so as to cover an inner wall of the opening part; a gate electrode formed inside the opening part via the gate insulating film; a source electrode formed on a surface of the third semiconductor layer; a drain electrode connected to a part corresponding to the gate electrode on another side of the semiconductor substrate; and a fourth electrode formed on the another side of the semiconductor substrate at a part corresponding to the source electrode.
    Type: Application
    Filed: April 24, 2013
    Publication date: September 5, 2013
    Applicant: Fujitsu Limited
    Inventors: Toshihiro Ohki, Masato Nishimori, Tadahiro Imada
  • Patent number: 8492784
    Abstract: A semiconductor device includes: a semiconductor chip including a nitride semiconductor layered structure including a carrier transit layer and a carrier supply layer; a first resin layer on the semiconductor chip, the first resin layer including a coupling agent; a second resin layer on the first resin layer, the second resin layer including a surfactant; and a sealing resin layer to seal the semiconductor chip with the first resin layer and the second resin layer.
    Type: Grant
    Filed: December 20, 2011
    Date of Patent: July 23, 2013
    Assignee: Fujitsu Limited
    Inventors: Keishiro Okamoto, Tadahiro Imada, Nobuhiro Imaizumi, Keiji Watanabe
  • Patent number: 8449787
    Abstract: A wet etching method that includes forming an insulating film on a substrate, and irradiating laser light to the insulating film during wet etching of the insulating film using an etching solution.
    Type: Grant
    Filed: February 22, 2008
    Date of Patent: May 28, 2013
    Assignee: Fujitsu Limited
    Inventors: Tadahiro Imada, Yoshihiro Nakata, Koji Nozaki
  • Patent number: 8431464
    Abstract: A silicic coating of 2.4 g/cm3 or higher density, obtained by forming a silicic coating precursor with the use of at least one type of silane compound having a photosensitive functional group and thereafter irradiating the silicic coating precursor with at least one type of light. This silicic coating can be used as a novel barrier film or stopper film for semiconductor device.
    Type: Grant
    Filed: February 4, 2010
    Date of Patent: April 30, 2013
    Assignee: Fujitsu Limited
    Inventors: Yasushi Kobayashi, Kouta Yoshikawa, Yoshihiro Nakata, Tadahiro Imada, Shirou Ozaki
  • Publication number: 20130099286
    Abstract: A first GaN layer, a first AlGaN layer, a second GaN layer and a third GaN layer are formed in layers on a substrate. A second AlGaN layer is formed on the sidewall of an opening formed in the multilayer structure. A gate electrode is formed to fill an electrode trench in an insulating film. A portion of the insulating film between the gate electrode and the second AlGaN layer functions as a gate insulating film. A source electrode is formed above the gate electrode and a drain electrode is formed below the gate electrode. This configuration enables implementation of a miniatuarizable, reliable vertical HEMT that has a sufficiently high withstand voltage and high output power and is capable of a normally-off operation without problems that could otherwise result from the use of a p-type compound semiconductor.
    Type: Application
    Filed: September 14, 2012
    Publication date: April 25, 2013
    Applicant: FUJITSU LIMITED
    Inventor: Tadahiro Imada
  • Publication number: 20130083567
    Abstract: A compound semiconductor device includes an electron transit layer having a first polarity, a p-type cap layer which is formed above the electron transit layer and has a second polarity, and an n-type cap layer which is formed on the p-type cap layer and has the first polarity. The n-type cap layer includes portions having different thicknesses.
    Type: Application
    Filed: July 18, 2012
    Publication date: April 4, 2013
    Applicant: FUJITSU LIMITED
    Inventor: Tadahiro Imada
  • Publication number: 20130083570
    Abstract: A semiconductor device includes a first element structure that includes a charge supply layer of first polarity; a charge channel layer of second polarity, the charge channel layer being formed above the charge supply layer and including a recess portion; and a first electrode formed in the recess portion above the charge channel layer.
    Type: Application
    Filed: August 29, 2012
    Publication date: April 4, 2013
    Applicant: FUJITSU LIMITED
    Inventor: Tadahiro Imada
  • Publication number: 20130082336
    Abstract: An AlGaN/GaN HEMT includes a compound semiconductor multilayer structure, an insertion metal layer in contact with a surface of the compound semiconductor multilayer structure, a gate insulating film formed on the insertion metal layer, and a gate electrode formed above the insertion metal layer with the gate insulating film between the gate electrode and the insertion metal layer.
    Type: Application
    Filed: July 19, 2012
    Publication date: April 4, 2013
    Applicant: FUJITSU LIMITED
    Inventor: Tadahiro IMADA
  • Patent number: 8404584
    Abstract: The method of manufacturing the semiconductor device includes forming an insulating film above a semiconductor substrate, forming an opening in the insulating film, forming a conductive film above the insulating film with the opening formed, removing the conductive film above the insulating film to bury the conductive film in the opening, and processing a surface of the insulating film with a silicon compound including Si—N or Si—Cl.
    Type: Grant
    Filed: May 2, 2011
    Date of Patent: March 26, 2013
    Assignee: Fujitsu Limited
    Inventors: Tadahiro Imada, Kouta Yoshikawa
  • Publication number: 20130062666
    Abstract: A compound semiconductor device includes a substrate; and a compound semiconductor layer disposed over the substrate, wherein the compound semiconductor layer includes a first region having first conductivity-type carriers generated by activating a first impurity and also includes a second region having carriers at lower concentration as compared to the first region, the carriers being generated by activating a second impurity which is the same type as the first impurity.
    Type: Application
    Filed: July 25, 2012
    Publication date: March 14, 2013
    Applicant: FUJITSU LIMITED
    Inventor: Tadahiro IMADA
  • Patent number: 8390099
    Abstract: An interconnection substrate including: a first insulating film made of a silicon compound, an adhesion enhancing layer formed on the first insulating film, and a second insulting film made of a silicon compound and formed on the adhesion enhancing layer, wherein the first insulating film and the second insulating film are combined together with a component having a structure represented by General Formula (1) described below: Si—CXHY—Si??General Formula (1) where y is equal to 2x and is an even integer.
    Type: Grant
    Filed: August 24, 2010
    Date of Patent: March 5, 2013
    Assignee: Fujitsu Limited
    Inventors: Shirou Ozaki, Yoshihiro Nakata, Tadahiro Imada, Yasushi Kobayashi
  • Publication number: 20120217626
    Abstract: A method for manufacturing a semiconductor device, includes: placing a seal layer including a connection conductive film on the surface so that the connection conductive film is in contact with an electrode of a semiconductor element and a lead; electrically coupling the electrode and the lead through the connection conductive film; and sealing the semiconductor element by the seal layer.
    Type: Application
    Filed: January 19, 2012
    Publication date: August 30, 2012
    Applicant: FUJITSU LIMITED
    Inventors: Taiji SAKAI, Kazukiyo Joshin, Tadahiro Imada, Nobuhiro Imaizumi, Keishiro Okamoto
  • Publication number: 20120220089
    Abstract: A gate electrode is formed so as to embed an electrode material in a recess for an electrode, which has been formed in a structure of stacked compound semiconductors, through a gate insulation film, and also a field plate electrode that comes in Schottky contact with the structure of the stacked compound semiconductors is formed by embedding an electrode material in a recess for an electrode, which has been formed in the structure of the stacked compound semiconductors so that the field plate electrode directly comes in contact with the structure of the stacked compound semiconductors at least on the bottom face of the recess for the electrode.
    Type: Application
    Filed: December 14, 2011
    Publication date: August 30, 2012
    Applicant: FUJITSU LIMITED
    Inventors: Tadahiro IMADA, Toshihide Kikkawa
  • Publication number: 20120218783
    Abstract: There is embodied a high-reliability high-voltage resistance compound semiconductor device capable of improving the speed of device operation, being high in avalanche resistance, being resistant to surges, eliminating the need to connect any external diodes when applied to, for example, an inverter circuit, and achieving stable operation even if holes are produced, in addition to alleviating the concentration of electric fields on a gate electrode and thereby realizing a further improvement in voltage resistance. A gate electrode is formed so as to fill an electrode recess formed in a structure of stacked compound semiconductors with an electrode material through a gate insulation film, and a field plate recess formed in the structure of stacked compound semiconductors is filled with a p-type semiconductor, thereby forming a field plate the p-type semiconductor layer of which has contact with the structure of stacked compound semiconductors.
    Type: Application
    Filed: December 15, 2011
    Publication date: August 30, 2012
    Applicant: FUJITSU LIMITED
    Inventor: Tadahiro IMADA
  • Publication number: 20120211901
    Abstract: A manufacturing of a semiconductor device includes forming one of a layer with a first metal and the layer with a second metal on one of a semiconductor chip mounting area of a support plate and a back surface of the semiconductor chip; forming the other of the layer with the first metal and the layer with the second metal on an area corresponding to a part of the area, in which one of the layer with the first metal and the layer with the second metal, of the other one of the semiconductor chip mounting area and the back surface of the semiconductor chip; and forming a layer which includes an alloy with the first metal and the second metal after positioning the semiconductor chip in the semiconductor chip mounting area to bond the semiconductor chip with the semiconductor chip mounting area.
    Type: Application
    Filed: January 23, 2012
    Publication date: August 23, 2012
    Applicant: FUJITSU LIMITED
    Inventors: Kozo SHIMIZU, Keishiro Okamoto, Nobuhiro Imaizumi, Tadahiro Imada, Keiji Watanabe