Patents by Inventor Yoshiro Baba

Yoshiro Baba 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: 9966441
    Abstract: A semiconductor device, including a first nitride semiconductor layer, a second nitride semiconductor layer provided on the first nitride semiconductor layer and having a band gap width larger than or equal to a band gap width of the first nitride semiconductor layer, first, second, and third electrodes provided on the second nitride semiconductor layer, an insulation layer provided on the second nitride semiconductor layer and between the first and second electrodes, and a conductor provided within the insulation layer between the second and third electrodes and connecting the second and third electrodes to each other, or the conductor provided within the insulation layer between the first and second electrodes and connecting the first and second electrodes to each other, the conductor including a plurality of conductive regions arranged in a first direction from the first electrode toward the second electrode, the conductive regions being electrically connected to one another.
    Type: Grant
    Filed: September 8, 2016
    Date of Patent: May 8, 2018
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takuo Kikuchi, Yoshiro Baba, Masahiko Yamamoto
  • Publication number: 20170084704
    Abstract: A semiconductor device, including a first nitride semiconductor layer, a second nitride semiconductor layer provided on the first nitride semiconductor layer and having a band gap width larger than or equal to a band gap width of the first nitride semiconductor layer, first, second, and third electrodes provided on the second nitride semiconductor layer, an insulation layer provided on the second nitride semiconductor layer and between the first and second electrodes, and a conductor provided within the insulation layer between the second and third electrodes and connecting the second and third electrodes to each other, or the conductor provided within the insulation layer between the first and second electrodes and connecting the first and second electrodes to each other, the conductor including-a plurality of conductive regions arranged in a first direction from the first electrode toward the second electrode, the conductive regions being electrically connected to one another.
    Type: Application
    Filed: September 8, 2016
    Publication date: March 23, 2017
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Takuo KIKUCHI, Yoshiro BABA, Masahiko YAMAMOTO
  • Patent number: 8058693
    Abstract: There is provided a semiconductor device having a switching element, including a first semiconductor layer including a first, second and third surfaces, a first electrode connected to the first semiconductor layer, a plurality of second semiconductor layers selectively configured on the first surface, a third semiconductor layer configured on the second semiconductor layer, a second electrode configured to be contacted with the second semiconductor layer and the third semiconductor layer, a gate electrode formed over the first semiconductor layer, a first region including a first tale region, a density distribution of crystalline defects being gradually increased therein, a peak region crossing a current path applying to a forward direction in a p-n junction, a second tale region continued from the peak region, and a second region including a third tale region, the density distribution of the crystalline defects being gradually increased therein.
    Type: Grant
    Filed: December 18, 2009
    Date of Patent: November 15, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Koichi Endo, Masaru Izumisawa, Takuma Hara, Syotaro Ono, Yoshiro Baba
  • Publication number: 20100187598
    Abstract: There is provided a semiconductor device having a switching element, including a first semiconductor layer including a first, second and third surfaces, a first electrode connected to the first semiconductor layer, a plurality of second semiconductor layers selectively configured on the first surface, a third semiconductor layer configured on the second semiconductor layer, a second electrode configured to be contacted with the second semiconductor layer and the third semiconductor layer, a gate electrode formed over the first semiconductor layer, a first region including a first tale region, a density distribution of crystalline defects being gradually increased therein, a peak region crossing a current path applying to a forward direction in a p-n junction, a second tale region continued from the peak region, and a second region including a third tale region, the density distribution of the crystalline defects being gradually increased therein.
    Type: Application
    Filed: December 18, 2009
    Publication date: July 29, 2010
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Koichi ENDO, Masaru IZUMISAWA, Takuma HARA, Syotaro ONO, Yoshiro BABA
  • Publication number: 20080242067
    Abstract: A semiconductor substrate is disclosed, which comprises a lightly doped substrate that contains impurities at a low concentration, a heavily doped diffusion layer which is formed over a top of the lightly doped substrate and is higher in impurity concentration than the lightly doped substrate, and an epitaxial layer which is formed over a top of the heavily doped diffusion layer and contains impurities at a lower concentration than the heavily doped diffusion layer.
    Type: Application
    Filed: April 29, 2008
    Publication date: October 2, 2008
    Inventors: Masanobu OGINO, Yoshikatsu Suto, Yoshiro Baba
  • Publication number: 20040124445
    Abstract: A semiconductor substrate is disclosed, which comprises a lightly doped substrate that contains impurities at a low concentration, a heavily doped diffusion layer which is formed over a top of the lightly doped substrate and is higher in impurity concentration than the lightly doped substrate, and an epitaxial layer which is formed over a top of the heavily doped diffusion layer and contains impurities at a lower concentration than the heavily doped diffusion layer.
    Type: Application
    Filed: November 17, 2003
    Publication date: July 1, 2004
    Inventors: Masanobu Ogino, Yoshikatsu Suto, Yoshiro Baba
  • Patent number: 6524894
    Abstract: An N+ buffer layer formed on the underside of an N− layer includes an inactive region having incompletely activated ions and an active region having highly activated ions. The carrier concentration of the active region is higher than that of the inactive region. In the inactive region, the electrical activation rate X of the ions is expressed as 1%≦X≦30%. It is thus possible to achieve a PT structure using a Raw wafer, which reduces manufacturing costs and suppresses power consumption.
    Type: Grant
    Filed: February 15, 2001
    Date of Patent: February 25, 2003
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hideki Nozaki, Yoshiro Baba, Motoshige Kobayashi
  • Patent number: 6476429
    Abstract: A power MOSFET includes an n−-drain layer, a drain contact layer disposed on a first side of the drain layer, a p-type base layer disposed on a second side of the drain layer, and an n-source layer disposed on the base layer. A gate electrode faces, through a gate insulating film, a channel region, which is part of the base layer between the drain and source layers. Source and drain electrodes are electrically connected to the source and drain contact layers, respectively. A plurality of hetero regions having a dielectric constant higher than that of the drain layer is disposed in the drain layer between the source and drain electrodes.
    Type: Grant
    Filed: April 11, 2001
    Date of Patent: November 5, 2002
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Yoshiro Baba
  • Publication number: 20020008258
    Abstract: A power MOSFET includes an n−-drain layer, a drain contact layer disposed on a first side of the drain layer, a p-type base layer disposed on a second side of the drain layer, and an n-source layer disposed on the base layer. A gate electrode faces, through a gate insulating film, a channel region, which is part of the base layer between the drain and source layers. Source and drain electrodes are electrically connected to the source and drain contact layers, respectively. A plurality of hetero regions having a dielectric constant higher than that of the drain layer is disposed in the drain layer between the source and drain electrodes.
    Type: Application
    Filed: April 11, 2001
    Publication date: January 24, 2002
    Inventor: Yoshiro Baba
  • Patent number: 6337498
    Abstract: A semiconductor device such as an IGBT having trench gates in a form of stripes, and manufacturing method, wherein concentration of stresses in only a single direction is relieved and the generation of a leakage current and crystal defects in the IGBT is prevented. In one embodiment, the inside of a terminal area of an IGBT is divided into a single gate pad area and plural element areas by a wiring area. The respective element areas are arranged in such a manner that the directions of trench gates formed in the respective element areas cross at right angles with respect to the directions of trench gates of respective adjacent element areas.
    Type: Grant
    Filed: February 12, 1999
    Date of Patent: January 8, 2002
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Shigeru Hasegawa, Hideo Matsuda, Yoshiro Baba, Masanobu Tsuchitani
  • Patent number: 6239464
    Abstract: A semiconductor device, which can have a uniform film on open ends of trenches by using materials having a different oxidation rate, and a fabrication method thereof are provided. The semiconductor device having trenches configured to have open ends covered with an oxidation film made of a material having an oxidation rate faster than that of a semiconductor substrate and a fabrication method thereof are provided.
    Type: Grant
    Filed: January 7, 1999
    Date of Patent: May 29, 2001
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masanobu Tsuchitani, Keita Suzuki, Akihiko Osawa, Yoshiro Baba
  • Patent number: 6060747
    Abstract: A semiconductor device is characterized in that source electrode contact regions, each of which is formed of a first conductivity type source layer and a second conductivity type base layer in a surface of a semiconductor surface, are formed at respective intersectional points of a diagonally-arranged lattice, and in that a trench having a gate electrode buried therein is formed so as to snake through the contact regions alternately. By virtue of the structure, the trench arrangement and source/base simultaneous contact quality are improved, to thereby increase a trench density (channel density) per unit area.
    Type: Grant
    Filed: September 23, 1998
    Date of Patent: May 9, 2000
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hideki Okumura, Akihiko Osawa, Yoshiro Baba, Noboru Matsuda, Masanobu Tsuchitani
  • Patent number: 6031276
    Abstract: A semiconductor device includes a plurality of defect layers separated from one another in the semiconductor layer. A distance separating any adjacent ones of the defect layers is kept such that they are prevented from contacting each other and those regions having effect of shortening a carrier lifetime overlap each other.
    Type: Grant
    Filed: October 15, 1997
    Date of Patent: February 29, 2000
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Akihiko Osawa, Yoshiro Baba, Masanobu Tsuchitani, Shizue Hori
  • Patent number: 6010950
    Abstract: The most distinctive feature of the present invention lies in that a warp and crystal defects can be prevented from occurring and a processing margin for forming an isolation groove can be improved in an intelligent power device including a power element section and an IC control section within one chip. A bonded wafer is obtained by bonding an active-layer substrate and a supporting substrate with an epitaxially grown silicon layer interposed therebetween so as to cover an oxide film selectively formed at the interface of the active-layer substrate. Isolation trenches are then formed in the bonded wafer to such a depth as to reach the oxide film from the element forming surface of the active-layer substrate. Thus, an IC controller is formed within a dielectric isolation region surrounded with the isolation trenches and the oxide film and accordingly the IC controller can effectively be isolated by a dielectric.
    Type: Grant
    Filed: February 19, 1998
    Date of Patent: January 4, 2000
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hideki Okumura, Akihiko Osawa, Yoshiro Baba
  • Patent number: 5917228
    Abstract: The present invention relates to a schottky-barrier diode capable of decreasing a leakage current due to damage generated on inner walls of trenches, and securing a large operation region for itself. In the device, an N.sup.- -type epitaxial layer is formed on a N.sup.+ -type silicon substrate. In a predetermined region in the epitaxial layer, a P.sup.+ -type base diffusion layer having high impurity concentration is formed. Trenches are formed through from the surface of the base diffusion layer to the epitaxial layer. In each of the trenches, an N.sup.- -type selective epitaxial growth region is formed. A schottky metal is formed on a surface comprising the surfaces of the base diffusion layer, which includes the selective epitaxial growth regions, and the epitaxial layer. Surface regions as the surfaces of the selective epitaxial growth regions filling the trenches function as diode operation regions.
    Type: Grant
    Filed: February 13, 1997
    Date of Patent: June 29, 1999
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Noboru Matsuda, Yoshiro Baba
  • Patent number: 5877540
    Abstract: A semiconductor device. A semiconductor substrate has a first conductivity. A first insulating layer is on the semiconductor substrate and has an opening so that a portion of the semiconductor substrate is exposed. A semiconductor layer has a second conductivity on the portion. A region in said semiconductor layer prevents a leakage current caused by a minute defect and faceting.
    Type: Grant
    Filed: December 13, 1996
    Date of Patent: March 2, 1999
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi Naruse, Hiroyuki Sugaya, Hidenori Saihara, Yoshiro Baba
  • Patent number: 5864180
    Abstract: A semiconductor device and a method for manufacturing the same, in which a leak current generated in a pn junction formed between a silicon substrate and an epitaxial layer can be reduced. A silicon oxide film is formed on a silicon substrate having a (100) crystal plane. The silicon oxide film is patterned to form an opened portion and an inclined surface on a pattern edge of the silicon oxide film. The inclined surface forms an angle of 54.74.+-.5.degree. with the silicon substrate. An epitaxial layer is formed in the opened portion by selective epitaxial growth.
    Type: Grant
    Filed: February 24, 1998
    Date of Patent: January 26, 1999
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Shizue Hori, Yoshiro Baba, Hiroyuki Sugaya, Hiroshi Naruse
  • Patent number: 5770514
    Abstract: In a vertical field effect transistor having a trench gate and a method of manufacturing the same according to the present invention, p-type base and n.sup.+ -type source diffusion layers are formed in this order in a surface region of an n.sup.31 -type epitaxial layer on an n.sup.+ -type semiconductor substrate. A trench is then provided to such a depth as to penetrate the diffusion layers. A dope polysilicon layer is deposited and buried into the trench with a gate insulation film interposed between them. The polysilicon layer is etched to have the same level as that of the entrance of the trench, and a dope polysilicon layer 18 is selectively grown thereon, thereby forming a trench gate in which an upper corner portion of the trench is not covered with a gate electrode. Consequently, the concentration of electric fields at the corner portion can be mitigated thereby to increase an absolute withstand voltage of the gate and the variations in threshold voltage can be suppressed in a BT test.
    Type: Grant
    Filed: January 22, 1997
    Date of Patent: June 23, 1998
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Noboru Matsuda, Yoshiro Baba, Satoshi Yanagiya, Masanobu Tsuchitani
  • Patent number: 5733810
    Abstract: A groove is formed on a semiconductor substrate. A mask material layer is so formed on the surface of the semiconductor substrate as to open a groove region. With the mask material layer used as a mask, a semiconductor layer is selectively formed on the semiconductor substrate exposed with the inner wall surface of the groove. Then, the mask material layer is removed. An insulating film is formed on the semiconductor layer formed on the inner wall surface of the groove and the surface of the semiconductor substrate. The groove is buried with a conductor.
    Type: Grant
    Filed: March 19, 1997
    Date of Patent: March 31, 1998
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yoshiro Baba, Hiroshi Naruse
  • Patent number: 5731637
    Abstract: The object of the present invention is to provide a method of manufacturing high-performance, high-breakdown-voltage semiconductor devices which suppresses an increase in the junction leakage current due to heavy metal contamination without increasing the number of manufacturing steps. A method of manufacturing semiconductor devices according to the invention, comprises the steps of ion-implanting one or more elements selected from a group of silicon, carbon, nitrogen, oxygen, hydrogen, argon, helium, and xenon into at least one surface of a semiconductor substrate of a first conductivity type at a dose of 1.times.10.sup.15 cm.sup.-2 or more to form a distortion layer, oxidizing the surface of the substrate to form an oxide film, ion-implanting impurities of a second conductivity type at a low concentration (a dose of less than 1.times.10.sup.15 cm.sup.-2) via the oxide film into the one surface of the substrate, ion-implanting impurities of the second conductivity type at a high concentration (a dose of 1.
    Type: Grant
    Filed: July 25, 1996
    Date of Patent: March 24, 1998
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Shizue Hori, Akihiko Osawa, Yoshiro Baba, Shigeo Yawata