Patents by Inventor Yasuhiko Onishi

Yasuhiko Onishi 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: 20050145933
    Abstract: A semiconductor device includes an active region, an alternating conductivity type layer, and an insulation region surrounding the alternating conductivity type layer provided in a periphery section as a voltage withstanding section. The insulation region is made of an insulator with the critical electric field strength higher than that of the semiconductor and reaches an n+-drain layer on the bottom surface side of the device from a surface on the side on which a surface structure section is formed. In the alternating conductivity type layer, the width of the p-type partition region adjacent to the insulation region is made narrower than the width of the p-type partition region not adjacent to the insulation region to ensure a balanced state of charges at the end of the drift section made up of the alternating conductivity type layer. A high breakdown voltage is ensured with the length of the periphery section shortened.
    Type: Application
    Filed: October 26, 2004
    Publication date: July 7, 2005
    Inventors: Yasuhiko Onishi, Takeyoshi Nishimura, Yasushi Niimura, Hitoshi Abe
  • Patent number: 6903418
    Abstract: A semiconductor device facilitates obtaining a higher breakdown voltage in the portion of the semiconductor chip around the drain drift region and improving the avalanche withstanding capability thereof. A vertical MOSFET according to the invention includes a drain layer; a drain drift region on drain layer, drain drift region including a first alternating conductivity type layer; a breakdown withstanding region (the peripheral region of the semiconductor chip) on drain layer and around drain drift region, breakdown withstanding region providing substantially no current path in the ON-state of the MOSFET, breakdown withstanding region being depleted in the OFF-state of the MOSFET, breakdown withstanding region including a second alternating conductivity type layer, and an under region below a gate pad, and the under region including a third alternating conductivity type layer.
    Type: Grant
    Filed: October 3, 2003
    Date of Patent: June 7, 2005
    Assignee: Fuji Electric Device Technology Co., Ltd.
    Inventors: Susumu Iwamoto, Tatsuhiko Fujihira, Katsunori Ueno, Yasuhiko Onishi, Takahiro Sato, Tatsuji Nagaoka
  • Patent number: 6900109
    Abstract: A semiconductor device includes an improved drain drift layer structure of alternating conductivity types, that is easy to manufacture, and that facilitates realizing a high current capacity and a high breakdown voltage and to provide a method of manufacturing the semiconductor device. The vertical MOSFET according to the invention includes an alternating-conductivity-type drain drift layer on an n+-type drain layer as a substrate. The alternating-conductivity-type drain drift layer is formed of n-type drift current path regions and p-type partition regions alternately arranged laterally with each other. The n-type drift current path regions and p-type partition regions extend in perpendicular to n+-type drain layer. Each p-type partition region is formed by vertically connecting p-type buried diffusion unit regions Up. The n-type drift current path regions are residual regions, left after connecting p-type buried diffusion unit regions Up, with the conductivity type thereof unchanged.
    Type: Grant
    Filed: February 28, 2003
    Date of Patent: May 31, 2005
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Yasuhiko Onishi, Tatsuhiko Fujihira, Susumu Iwamoto, Takahiro Sato
  • Publication number: 20050017292
    Abstract: Disclosed is a semiconductor device facilitating a peripheral portion thereof with a breakdown voltage higher than the breakdown voltage in the drain drift layer without employing a guard ring or field plate. A preferred embodiment includes a drain drift region with a first alternating conductivity type layer formed of n drift current path regions and p partition regions arranged alternately with each other, and a breakdown withstanding region with a second alternating conductivity type layer formed of n regions and p regions arranged alternately with each other, the breakdown withstanding region providing no current path in the ON-state of the device and being depleted in the OFF-state of the device. Since depletion layers expand in both directions from multiple pn-junctions into n regions and p regions in the OFF-state of the device, the adjacent areas of p-type base regions, the outer area of the semiconductor chip and the deep area of the semiconductor chip are depleted.
    Type: Application
    Filed: August 25, 2004
    Publication date: January 27, 2005
    Inventors: Yasuhiko Onishi, Tatsuhiko Fujihira, Katsunori Ueno, Susumu Iwamoto, Takahiro Sato, Tatsuji Nagaoka
  • Patent number: 6825565
    Abstract: A semiconductor device includes a drift region, which includes a first alternating conductivity type layer, and a peripheral region, which includes a second alternating conductivity type layer and a third alternating conductivity type layer in the surface portion of the peripheral region. The first layer includes first n-type regions and first p-type regions arranged alternately at a first pitch. The second layer is continuous with the first layer and includes second n-type regions and second p-type regions arranged alternately at the first pitch. The impurity concentration in the second layer is almost the same as the impurity concentration in the first layer. The third layer includes third n-type regions and third p-type regions arranged alternately at a second pitch. The third layer can be doped more lightly than the first and second alternating conductivity type layers. The second pitch can be the same as the first pitch or smaller.
    Type: Grant
    Filed: January 30, 2003
    Date of Patent: November 30, 2004
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Yasuhiko Onishi, Tatsuji Nagaoka, Susumu Iwamoto, Takahiro Sato
  • Patent number: 6825537
    Abstract: In a trench super junction semiconductor element having a parallel p-n junction layer 14 with n-drift regions 12 and p-partition regions 13, both extending in a depth direction, being alternately joined, a part 20 in a shape of a three-dimensional curved surface in the end portion of each of trenches is formed in a p-partition region 13. A section in the p-partition region 13 surrounding the part 20 in a shape of a three-dimensional curved surface of the end portion of each of the trenches is made as a p+-region 21 in which an impurity concentration is higher than that in a section thereunder so that an electric field is increased at a boundary between the p+-region 21 and the n-drift region 12, thereby lessening electric field concentration to the part 20 in a shape of a three-dimensional curved surface of the end portion of the trench.
    Type: Grant
    Filed: October 10, 2003
    Date of Patent: November 30, 2004
    Assignee: Fuji Electric Device Technology Co., Ltd.
    Inventors: Susumu Iwamoto, Yasuhiko Onishi, Takahiro Sato, Tatsuji Nagaoka
  • Publication number: 20040212032
    Abstract: A lateral semiconductor device includes an alternating conductivity type layer for providing a first semiconductor current path in the ON-state of the device and for being depleted in the OFF-state of the device, that has an improved structure for realizing a high breakdown voltage in the curved sections of the alternating conductivity type layer.
    Type: Application
    Filed: May 19, 2004
    Publication date: October 28, 2004
    Applicant: Fuji Electric Co., Ltd.
    Inventors: Yasuhiko Onishi, Tatsuhiko Fujihira, Susumu Iwamoto, Takahiro Sato
  • Patent number: 6768167
    Abstract: A MIS semiconductor device has a greatly improved relation between the on-resistance and the switching time by forming trench completely through a p base region and positioning the trench adjacent to a gate electrode, and then implanting n-type impurity ions using the gate electrode as a mask to form a second drain region, which also serves as a drift region.
    Type: Grant
    Filed: May 21, 2003
    Date of Patent: July 27, 2004
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Tatsuji Nagaoka, Tatsuhiko Fujihira, Yasuhiko Onishi
  • Publication number: 20040135228
    Abstract: In a trench super junction semiconductor element having a parallel p-n junction layer 14 with n-drift regions 12 and p-partition regions 13, both extending in a depth direction, being alternately joined, a part 20 in a shape of a three-dimensional curved surface in the end portion of each of trenches is formed in a p-partition region 13. A section in the p-partition region 13 surrounding the part 20 in a shape of a three-dimensional curved surface of the end portion of each of the trenches is made as a p+-region 21 in which an impurity concentration is higher than that in a section thereunder so that an electric field is increased at a boundary between the p+-region 21 and the n-drift region 12, thereby lessening electric field concentration to the part 20 in a shape of a three-dimensional curved surface of the end portion of the trench.
    Type: Application
    Filed: October 10, 2003
    Publication date: July 15, 2004
    Inventors: Susumu Iwamoto, Yasuhiko Onishi, Takahiro Sato, Tatsuji Nagaoka
  • Publication number: 20040124465
    Abstract: Disclosed is a semiconductor device facilitating a peripheral portion thereof with a breakdown voltage higher than the breakdown voltage in the drain drift layer without employing a guard ring or field plate. A preferred embodiment includes a drain drift region with a first alternating conductivity type layer formed of n drift current path regions and p partition regions arranged alternately with each other, and a breakdown withstanding region with a second alternating conductivity type layer formed of n regions and p regions arranged alternately with each other, the breakdown withstanding region providing no current path in the ON-state of the device and being depleted in the OFF-state of the device. Since depletion layers expand in both directions from multiple pn-junctions into n regions and p regions in the OFF-state of the device, the adjacent areas of p-type base regions, the outer area of the semiconductor chip and the deep area of the semiconductor chip are depleted.
    Type: Application
    Filed: December 12, 2003
    Publication date: July 1, 2004
    Applicant: Fuji Electric Co., Ltd.
    Inventors: Yasuhiko Onishi, Tatsuhiko Fujihira, Katsunori Ueno, Susumu Iwamoto, Takahiro Sato, Tatsuji Nagaoka
  • Patent number: 6756636
    Abstract: A lateral semiconductor device includes an alternating conductivity type layer for providing a first semiconductor current path in the ON-state of the device and for being depleted in the OFF-state of the device, that has an improved structure for realizing a high breakdown voltage in the curved sections of the alternating conductivity type layer.
    Type: Grant
    Filed: April 27, 2001
    Date of Patent: June 29, 2004
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Yasuhiko Onishi, Tatsuhiko Fujihira, Susumu Iwamoto, Takahiro Sato
  • Patent number: 6724042
    Abstract: Disclosed is a semiconductor device facilitating a peripheral portion thereof with a breakdown voltage higher than the breakdown voltage in the drain drift layer without employing a guard ring or field plate. A preferred embodiment includes a drain drift region with a first alternating conductivity type layer formed of n drift current path regions and p partition regions arranged alternately with each other, and a breakdown withstanding region with a second alternating conductivity type layer formed of n regions and p regions arranged alternately with each other, the breakdown withstanding region providing no current path in the ON-state of the device and being depleted in the OFF-state of the device. Since depletion layers expand in both directions from multiple pn-junctions into n regions and p regions in the OFF-state of the device, the adjacent areas of p-type base regions, the outer area of the semiconductor chip and the deep area of the semiconductor chip are depleted.
    Type: Grant
    Filed: February 9, 2001
    Date of Patent: April 20, 2004
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Yasuhiko Onishi, Tatsuhiko Fujihira, Katsunori Ueno, Susumu Iwamoto, Takahiro Sato, Tatsuji Nagaoka
  • Publication number: 20040065921
    Abstract: A semiconductor device facilitates obtaining a higher breakdown voltage in the portion of the semiconductor chip around the drain drift region and improving the avalanche withstanding capability thereof. A vertical MOSFET according to the invention includes a drain layer; a drain drift region on drain layer, drain drift region including a first alternating conductivity type layer; a breakdown withstanding region (the peripheral region of the semiconductor chip) on drain layer and around drain drift region, breakdown withstanding region providing substantially no current path in the ON-state of the MOSFET, breakdown withstanding region being depleted in the OFF-state of the MOSFET, breakdown withstanding region including a second alternating conductivity type layer, and an under region below a gate pad, and the under region including a third alternating conductivity type layer.
    Type: Application
    Filed: October 3, 2003
    Publication date: April 8, 2004
    Applicant: Fuji Electric Co., Ltd.
    Inventors: Susumu Iwamoto, Tatsuhiko Fujihira, Katsunori Ueno, Yasuhiko Onishi, Takahiro Sato, Tatsuji Nagaoka
  • Publication number: 20040056284
    Abstract: A MIS semiconductor device has a greatly improved relation between the on-resistance and the switching time by forming trench completely through a p base region and positioning the trench adjacent to a gate electrode, and then implanting n-type impurity ions using the gate electrode as a mask to form a second drain region, which also serves as a drift region.
    Type: Application
    Filed: May 21, 2003
    Publication date: March 25, 2004
    Inventors: Tatsuji Nagaoka, Tatsuhiko Fujihira, Yasuhiko Onishi
  • Patent number: 6700141
    Abstract: A reliable super-junction semiconductor device is provided that facilitates relaxing the tradeoff relation between the on-resistance and the breakdown voltage and improving the avalanche withstanding capability under an inductive load. The super-junction semiconductor device includes an active region including a thin first alternating conductivity type layer and a heavily doped n+-type intermediate drain layer between first alternating conductivity type layer and an n++-type drain layer, and a breakdown withstanding region including a thick second alternating conductivity type layer. Alternatively, active region includes a first alternating conductivity type layer and a third alternating conductivity type layer between first alternating conductivity type layer and n++-type drain layer, third alternating conductivity type layer being doped more heavily than first alternating conductivity type layer.
    Type: Grant
    Filed: October 17, 2001
    Date of Patent: March 2, 2004
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Susumu Iwamoto, Tatsuhiko Fujihira, Katsunori Ueno, Yasuhiko Onishi, Takahiro Sato
  • Patent number: 6696728
    Abstract: To provide a super-junction MOSFET reducing the tradeoff relation between the on-resistance and the breakdown voltage greatly and having a peripheral structure, which facilitates reducing the leakage current in the OFF-state thereof and stabilizing the breakdown voltage thereof. The vertical MOSFET according to the invention includes a drain drift region including a first alternating conductivity type layer; a breakdown withstanding region (peripheral region) including a second alternating conductivity type layer around drain drift region, second alternating conductivity type layer being formed of layer-shaped vertically-extending n-type regions and layer-shaped vertically-extending p-type regions laminated alternately; an n-type region around second alternating conductivity type layer; and a p-type region formed in the surface portion of n-type region to reduce the leakage current in the OFF-state of the MOSFET.
    Type: Grant
    Filed: March 15, 2002
    Date of Patent: February 24, 2004
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Yasuhiko Onishi, Tatsuhiko Fujihira, Katsunori Ueno, Susumu Iwamoto, Takahiro Sato, Tatsuji Nagaoka
  • Patent number: 6693323
    Abstract: A method of manufacture reduces costs and provides an excellent mass-productivity, a super-junction semiconductor device, that facilitates reducing times of heat treatment of the alternating conductivity type layer subjects, and preventing the characteristics of the alternating conductivity type layer from being impaired. A surface MOSFET structure, including p-type base regions, p+-type contact region in p-type base region, an n+-type source region in p-type base region, a gate electrode layer and a source electrode, is formed in the surface portion of an n-type semiconductor substrate through the usual double diffusion MOSFET manufacturing process. An oxide film is deposited by the CVD method on the back surface of the semiconductor substrate, a resist mask for defining p-type partition regions is formed on the oxide film, oxide film is removed by ion etching, and trenches are dug.
    Type: Grant
    Filed: September 9, 2002
    Date of Patent: February 17, 2004
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Takahiro Sato, Katsunori Ueno, Tatsuhiko Fujihira, Kenji Kunihara, Yasuhiko Onishi, Susumu Iwamoto
  • Patent number: 6677643
    Abstract: A super-junction semiconductor is provided that facilitates easy mass-production thereof, reducing the tradeoff relation between the on-resistance and the breakdown voltage, obtaining a high breakdown voltage and reducing the on-resistance to increase the current capacity thereof. The super-junction semiconductor device includes a semiconductor chip having a first major surface and a second major surface facing in opposite to the first major surface; a layer with low electrical resistance on the side of the second major surface; a first alternating conductivity type layer on low resistance layer, and a second alternating conductivity type layer on the first alternating conductivity type layer. The first alternating conductivity type layer including regions of a first conductivity type and regions of a second conductivity type arranged alternately with each other.
    Type: Grant
    Filed: March 19, 2001
    Date of Patent: January 13, 2004
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Susumu Iwamoto, Tatsuhiko Fujihira, Katsunori Ueno, Yasuhiko Onishi, Takahiro Sato
  • Patent number: 6674126
    Abstract: A semiconductor device facilitates obtaining a higher breakdown voltage in the portion of the semiconductor chip around the drain drift region and improving the avalanche withstanding capability thereof. A vertical MOSFET according to the invention includes a drain layer; a drain drift region on drain layer, drain drift region including a first alternating conductivity type layer; a breakdown withstanding region (the peripheral region of the semiconductor chip) on drain layer and around drain drift region, breakdown withstanding region providing substantially no current path in the ON-state of the MOSFET, breakdown withstanding region being depleted in the OFF-state of the MOSFET, breakdown withstanding region including a second alternating conductivity type layer, and an under region below a gate pad, and the under region including a third alternating conductivity type layer.
    Type: Grant
    Filed: February 11, 2002
    Date of Patent: January 6, 2004
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Susumu Iwamoto, Tatsuhiko Fujihira, Katsunori Ueno, Yasuhiko Onishi, Takahiro Sato, Tatsuji Nagaoka
  • Publication number: 20030176031
    Abstract: A semiconductor device includes a drift region, which includes a first alternating conductivity type layer, and a peripheral region, which includes a second alternating conductivity type layer and a third alternating conductivity type layer in the surface portion of the peripheral region. The first layer includes first n-type regions and first p-type regions arranged alternately at a first pitch. The second layer is continuous with the first layer and includes second n-type regions and second p-type regions arranged alternately at the first pitch. The impurity concentration in the second layer is almost the same as the impurity concentration in the first layer. The third layer includes third n-type regions and third p-type regions arranged alternately at a second pitch. The third layer can be doped more lightly than the first and second alternating conductivity type layers. The second pitch can be the same as the first pitch or smaller.
    Type: Application
    Filed: January 30, 2003
    Publication date: September 18, 2003
    Inventors: Yasuhiko Onishi, Tatsuji Nagaoka, Susumu Iwamoto, Takahiro Sato