Patents by Inventor Takashi Onizawa

Takashi Onizawa 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: 20190296138
    Abstract: A semiconductor apparatus according to the present embodiment is a semiconductor apparatus including a first nitride semiconductor layer including a first region having a first upper surface, a second region having a second upper surface parallel to the first upper surface, and a third region provided between the first region and the second region and having a third upper surface inclined with respect to the first upper surface and the second upper surface; a second nitride semiconductor layer including a fourth upper surface provided above the first upper surface, a fifth upper surface provided above the second upper surface, and a sixth upper surface provided above the third upper surface and being parallel to the third upper surface, the fourth upper surface being parallel to the first upper surface and being a +c face, the fifth upper surface parallel to the second upper surface and being a +c face, and the second nitride semiconductor having a bandgap larger than that of the first nitride semiconductor l
    Type: Application
    Filed: August 31, 2018
    Publication date: September 26, 2019
    Applicants: Kabushiki Kaisha Toshiba, Toshiba Electronic Devices & Storage Corporation
    Inventors: Hiroaki HAYASHI, Seiji INUMIYA, Takashi ONIZAWA, Emiko INOUE
  • Patent number: 9722067
    Abstract: A semiconductor device includes a first nitride semiconductor layer, a source electrode on the first nitride semiconductor layer, a drain electrode on the first nitride semiconductor layer, a gate electrode on the first nitride semiconductor layer and between the source electrode and the drain electrode, a gate field plate electrode that is separated from the first nitride semiconductor layer, and includes one end in direct contact with the gate electrode, and the other end positioned between the gate electrode and the drain electrode, a first interlayer insulating film that is separated from the gate electrode and is between the gate field plate electrode and the first nitride semiconductor layer, and a second interlayer insulating film that is between the gate electrode and the first interlayer insulating film and has a dielectric constant higher than a dielectric constant of the first interlayer insulating film.
    Type: Grant
    Filed: March 7, 2016
    Date of Patent: August 1, 2017
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventors: Tasuku Ono, Takashi Onizawa, Yoshikazu Suzuki
  • Publication number: 20170077284
    Abstract: A semiconductor device includes a first nitride semiconductor layer, a source electrode on the first nitride semiconductor layer, a drain electrode on the first nitride semiconductor layer, a gate electrode on the first nitride semiconductor layer and between the source electrode and the drain electrode, a gate field plate electrode that is separated from the first nitride semiconductor layer, and includes one end in direct contact with the gate electrode, and the other end positioned between the gate electrode and the drain electrode, a first interlayer insulating film that is separated from the gate electrode and is between the gate field plate electrode and the first nitride semiconductor layer, and a second interlayer insulating film that is between the gate electrode and the first interlayer insulating film and has a dielectric constant higher than a dielectric constant of the first interlayer insulating film.
    Type: Application
    Filed: March 7, 2016
    Publication date: March 16, 2017
    Inventors: Tasuku ONO, Takashi ONIZAWA, Yoshikazu SUZUKI
  • Publication number: 20170077279
    Abstract: A semiconductor device includes a semiconductor substrate which includes a first surface, a second surface, and an end portion, the semiconductor substrate including a first region of a p-type and a second region of an n-type provided in a corner portion of the semiconductor substrate between the first surface and the end surface, a nitride semiconductor layer on the first surface, and an electrode on the nitride semiconductor layer.
    Type: Application
    Filed: March 4, 2016
    Publication date: March 16, 2017
    Inventor: Takashi ONIZAWA
  • Publication number: 20160268410
    Abstract: A semiconductor device includes: a substrate; a first compound semiconductor layer provided on the substrate; a second compound semiconductor layer provided on the first compound semiconductor layer and having a band gap larger than that of the first compound semiconductor layer; a first element isolation region provided in the first compound semiconductor layer and the second compound semiconductor layer; and a first electrode and a second electrode which are electrically connected to a first conductive region formed from the first and second compound semiconductor layers arranged outside the first element isolation region.
    Type: Application
    Filed: September 1, 2015
    Publication date: September 15, 2016
    Inventors: Takashi Onizawa, Yoshiharu Takada
  • Publication number: 20160218067
    Abstract: A semiconductor device includes a substrate, a nitride semiconductor layer formed on the substrate, and a protection layer, comprising carbon, covering a side surface of the nitride semiconductor layer.
    Type: Application
    Filed: August 31, 2015
    Publication date: July 28, 2016
    Inventors: Shingo MASUKO, Yoshiharu TAKADA, Takashi ONIZAWA, Yasuhiro ISOBE, Kohei OASA
  • Patent number: 9362110
    Abstract: A first nitride semiconductor layer contains Ga. The first nitride semiconductor layer is, for example, a GaN layer, an AlGaN layer, or an AlInGaN layer. Then, an aluminum oxide layer has tetra-coordinated Al atoms each surrounded by four ? atoms and hexa-coordinated Al atoms each surrounded by six ? atoms as Al atoms in the interface region with respect to the first nitride semiconductor layer. The interface region is a region apart, for example, by 1.5 nm or less from the interface with respect to the first nitride semiconductor layer. Then, in the interface region, the tetra-coordinated Al atoms are present by 30 at % or more and less than 50 at % based on the total number of Al atoms.
    Type: Grant
    Filed: August 23, 2014
    Date of Patent: June 7, 2016
    Assignee: Renesas Electronics Corporation
    Inventors: Nobuyuki Ikarashi, Takashi Onizawa, Motofumi Saitoh
  • Patent number: 9330905
    Abstract: A semiconductor device, in which the generation of interface states in the interface region between a nitride semiconductor layer and an aluminum oxide layer is suppressed, includes a first nitride semiconductor layer and an aluminum oxide layer. The first nitride semiconductor layer includes Ga. The aluminum oxide layer directly contacts the upper surface of the first nitride semiconductor layer, and includes H (hydrogen) atoms at least within a defined region from the interface with the first nitride semiconductor layer. In addition, the peak value of an H atom concentration in the above region is in a range of 1×1020 cm?3 to 5×1021 cm?3.
    Type: Grant
    Filed: March 18, 2013
    Date of Patent: May 3, 2016
    Assignee: Renesas Electronics Corporation
    Inventor: Takashi Onizawa
  • Publication number: 20160086939
    Abstract: A first contact, a second impurity region, and a second low-concentration impurity region form a Schottky barrier diode. The second impurity region has the same impurity concentration as those of first impurity regions, and thus can be formed in the same process as forming the first impurity regions. In addition, the second low-concentration impurity region has the same impurity concentration as those of first low-concentration impurity regions, and thus can be formed in the same process as forming the first low-concentration impurity regions.
    Type: Application
    Filed: September 23, 2015
    Publication date: March 24, 2016
    Inventors: Hiroshi Takeda, Kiyoshi Takeuchi, Takashi Onizawa, Masayasu Tanaka
  • Publication number: 20160049375
    Abstract: A semiconductor device includes a substrate which includes a first face. The device also includes a buffer layer, a semiconductor layer, source and drain electrodes, and a gate electrode. A trench is formed on the semiconductor layer so that the trench surrounds the source electrode, the drain electrode, and the gate electrode in a plan view, the trench passes through the semiconductor layer and the buffer layer, and a bottom of the trench reaches at least an inside of the substrate. A distance from the first face of the substrate to the bottom of the trench is 100 nm or more in a thickness direction of the substrate.
    Type: Application
    Filed: October 28, 2015
    Publication date: February 18, 2016
    Inventors: Ippei KUME, Takashi ONIZAWA, Takashi HASE, Shigeru HIRAO, Tadatoshi DANNO
  • Patent number: 9196731
    Abstract: Sometimes to warp a group III nitride semiconductor and a silicon by the stress of the group III nitride semiconductor acting on the silicon. A semiconductor device includes a substrate, a buffer layer, and a semiconductor layer. A trench is formed on a sixth face of the semiconductor layer. The trench passes through the semiconductor layer and the buffer layer. The bottom of the trench reaches at least the inside of the substrate.
    Type: Grant
    Filed: August 8, 2014
    Date of Patent: November 24, 2015
    Assignee: Renesas Electronics Corporation
    Inventors: Ippei Kume, Takashi Onizawa, Takashi Hase, Shigeru Hirao, Tadatoshi Danno
  • Patent number: 9178059
    Abstract: A first contact, a second impurity region, and a second low-concentration impurity region form a Schottky barrier diode. The second impurity region has the same impurity concentration as those of first impurity regions, and thus can be formed in the same process as forming the first impurity regions. In addition, the second low-concentration impurity region has the same impurity concentration as those of first low-concentration impurity regions, and thus can be formed in the same process as forming the first low-concentration impurity regions.
    Type: Grant
    Filed: September 26, 2013
    Date of Patent: November 3, 2015
    Assignee: Renesas Electronics Corporation
    Inventors: Hiroshi Takeda, Kiyoshi Takeuchi, Takashi Onizawa, Masayasu Tanaka
  • Publication number: 20150060942
    Abstract: Sometimes to warp a group III nitride semiconductor and a silicon by the stress of the group III nitride semiconductor acting on the silicon. A semiconductor device includes a substrate, a buffer layer, and a semiconductor layer. A trench is formed on a sixth face of the semiconductor layer. The trench passes through the semiconductor layer and the buffer layer. The bottom of the trench reaches at least the inside of the substrate.
    Type: Application
    Filed: August 8, 2014
    Publication date: March 5, 2015
    Inventors: Ippei Kume, Takashi Onizawa, Takashi Hase, Shigeru Hirao, Tadatoshi Danno
  • Publication number: 20140363982
    Abstract: A first nitride semiconductor layer contains Ga. The first nitride semiconductor layer is, for example, a GaN layer, an AlGaN layer, or an AlInGaN layer. Then, an aluminum oxide layer has tetra-coordinated Al atoms each surrounded by four ? atoms and hexa-coordinated Al atoms each surrounded by six ? atoms as Al atoms in the interface region with respect to the first nitride semiconductor layer. The interface region is a region apart, for example, by 1.5 nm or less from the interface with respect to the first nitride semiconductor layer. Then, in the interface region, the tetra-coordinated Al atoms are present by 30 at % or more and less than 50 at % based on the total number of Al atoms.
    Type: Application
    Filed: August 23, 2014
    Publication date: December 11, 2014
    Inventors: Nobuyuki Ikarashi, Takashi Onizawa, Motofumi Saitoh
  • Patent number: 8872234
    Abstract: A first nitride semiconductor layer contains Ga. The first nitride semiconductor layer is, for example, a GaN layer, an AlGaN layer, or an AlInGaN layer. Then, an aluminum oxide layer has tetra-coordinated Al atoms each surrounded by four O atoms and hexa-coordinated Al atoms each surrounded by six O atoms as Al atoms in the interface region with respect to the first nitride semiconductor layer. The interface region is a region apart, for example, by 1.5 nm or less from the interface with respect to the first nitride semiconductor layer. Then, in the interface region, the tetra-coordinated Al atoms are present by 30 at % or more and less than 50 at % based on the total number of Al atoms.
    Type: Grant
    Filed: January 4, 2013
    Date of Patent: October 28, 2014
    Assignee: Renesas Electronics Corporation
    Inventors: Nobuyuki Ikarashi, Takashi Onizawa, Motofumi Saitoh
  • Publication number: 20140084386
    Abstract: A first contact, a second impurity region, and a second low-concentration impurity region form a Schottky barrier diode. The second impurity region has the same impurity concentration as those of first impurity regions, and thus can be formed in the same process as forming the first impurity regions. In addition, the second low-concentration impurity region has the same impurity concentration as those of first low-concentration impurity regions, and thus can be formed in the same process as forming the first low-concentration impurity regions.
    Type: Application
    Filed: September 26, 2013
    Publication date: March 27, 2014
    Applicant: Renesas Electronics Corporation
    Inventors: Hiroshi Takeda, Kiyoshi Takeuchi, Takashi Onizawa, Masayasu Tanaka
  • Publication number: 20130264576
    Abstract: A semiconductor device, in which the generation of interface states in the interface region between a nitride semiconductor layer and an aluminum oxide layer is suppressed, includes a first nitride semiconductor layer and an aluminum oxide layer. The first nitride semiconductor layer includes Ga. The aluminum oxide layer directly contacts the upper surface of the first nitride semiconductor layer, and includes H (hydrogen) atoms at least within a defined region from the interface with the first nitride semiconductor layer. In addition, the peak value of an H atom concentration in the above region is in a range of 1×1020 cm?3 to 5×1021 cm?3.
    Type: Application
    Filed: March 18, 2013
    Publication date: October 10, 2013
    Applicant: Renesas Electronics Corporation
    Inventor: Takashi Onizawa
  • Patent number: 8551842
    Abstract: A method of manufacturing a semiconductor device includes performing heat treatment for activating impurities of a transistor having a gate electrode over a gate insulating film with a higher relative permittivity than a silicon oxynitride film or a silicon oxide film. In the heat treatment, a first heat treatment, in which a wafer surface is heated at a temperature of 800 to 1000° C. in 5 to 50 milliseconds by low-output flash lamp annealing or laser annealing, and a second heat treatment, in which the wafer surface is heated at a temperature equal to or more than of 1100° C. in 0.1 to 10 milliseconds by flash lamp annealing or laser annealing with a higher output than in the first heat treatment, are performed in this order.
    Type: Grant
    Filed: May 27, 2010
    Date of Patent: October 8, 2013
    Assignee: Renesas Electronics Corporation
    Inventor: Takashi Onizawa
  • Publication number: 20100317200
    Abstract: A method of manufacturing a semiconductor device includes performing heat treatment for activating impurities of a transistor having a gate electrode over a gate insulating film with a higher relative permittivity than a silicon oxynitride film or a silicon oxide film. In the heat treatment, a first heat treatment, in which a wafer surface is heated at a temperature of 800 to 1000° C. in 5 to 50 milliseconds by low-output flash lamp annealing or laser annealing, and a second heat treatment, in which the wafer surface is heated at a temperature equal to or more than of 1100° C. in 0.1 to 10 milliseconds by flash lamp annealing or laser annealing with a higher output than in the first heat treatment, are performed in this order.
    Type: Application
    Filed: May 27, 2010
    Publication date: December 16, 2010
    Applicant: NEC Electronics Corporation
    Inventor: Takashi Onizawa
  • Publication number: 20090311840
    Abstract: A method of manufacturing a semiconductor device includes forming, over a substrate, a gate insulating film containing a high-k insulating film which is composed of a material having a dielectric constant larger than that of silicon dioxide film; forming a gate electrode containing a metal over the gate insulating film; forming extension regions by implanting an dopant into the substrate using the gate electrode as a mask; and annealing the substrate, having the dopant implanted therein, by flash lamp annealing or laser annealing; wherein the annealing further includes: a first step irradiating a substrate with a light pulse having a predetermined peak intensity; and a second step irradiating a substrate with light pulses having peak intensities lower than that of the light pulse used in the first step.
    Type: Application
    Filed: June 15, 2009
    Publication date: December 17, 2009
    Applicant: NEC ELECTRONICS CORPORATION
    Inventor: Takashi ONIZAWA