Patents by Inventor Tatsuhiko Fujihira

Tatsuhiko Fujihira 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: 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
  • Publication number: 20040113200
    Abstract: A MOS semiconductor device includes n−-type surface regions, which are extended portions of an n−-type drift layer 12 extended to the surface of the semiconductor chip. Each n−-type surface region 14 is shaped with a stripe surrounded by a p-type well region. The surface area ratio between n−-type surface regions 14 and p-type well region 13 including an n+-type region 15 is from 0.01 to 0.2. The MOS semiconductor device further includes, in the breakdown withstanding region thereof, a plurality of guard rings, the number of which is equal to or more than the number n calculated from the following equation n=(Breakdown voltage Vbr (V))/100, and the spacing between the adjacent guard rings is set at 1 &mgr;m or less.
    Type: Application
    Filed: August 22, 2003
    Publication date: June 17, 2004
    Applicant: Fuji Electric Co., Ltd.
    Inventors: Takashi Kobayashi, Tatsuhiko Fujihira, Hitoshi Abe, Yasushi Niimura, Masanori Inoue
  • Patent number: 6734496
    Abstract: A semiconductor device has a drift region in which a drift current flows if it is in the ON mode and which is depleted if it is in the OFF mode. The drift region is formed as a structure having a plurality of first conductive type divided drift regions and a plurality of second conductive type compartment regions in which each of the compartment regions is positioned among the adjacent drift regions in parallel to make p-n junctions, respectively.
    Type: Grant
    Filed: April 5, 2002
    Date of Patent: May 11, 2004
    Assignee: Fuji Electric Co., Ltd.
    Inventor: Tatsuhiko Fujihira
  • 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
  • Patent number: 6724040
    Abstract: A semiconductor device has a drift region in which a drift current flows if it is in the ON mode and which is depleted if it is in the OFF mode. The drift region is formed as a structure having a plurality of first conductive type divided drift regions and a plurality of second conductive type compartment regions in which each of the compartment regions is positioned among the adjacent drift regions in parallel to make p-n junctions, respectively.
    Type: Grant
    Filed: April 5, 2002
    Date of Patent: April 20, 2004
    Assignee: Fuji Electric Co., Ltd.
    Inventor: Tatsuhiko Fujihira
  • Patent number: 6720615
    Abstract: A semiconductor device has a drift region in which a drift current flows if it is in the ON mode and which is depleted if it is in the OFF mode. The drift region is formed as a structure having a plurality of first conductive type divided drift regions and a plurality of second conductive type compartment regions in which each of the compartment regions is positioned among the adjacent drift regions in parallel to make p-n junctions, respectively.
    Type: Grant
    Filed: April 5, 2002
    Date of Patent: April 13, 2004
    Assignee: Fuji Electric Co., Ltd.
    Inventor: Tatsuhiko Fujihira
  • 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: 6700157
    Abstract: A semiconductor device has a drift region in which a drift current flows if it is in the ON mode and which is depleted if it is in the OFF mode. The drift region is formed as a structure having a plurality of first conductive type divided drift regions and a plurality of second conductive type compartment regions in which each of the compartment regions is positioned among the adjacent drift regions in parallel to make p-n junctions, respectively.
    Type: Grant
    Filed: April 5, 2002
    Date of Patent: March 2, 2004
    Assignee: Fuji Electric Co., Ltd.
    Inventor: Tatsuhiko Fujihira
  • 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
  • Publication number: 20040026728
    Abstract: A semiconductor device realizes a high electrostatic discharge withstanding capability and a high surge withstanding capability within the narrow chip area of a lateral MOSFET used in integrated intelligent switching devices, double-integration-type signal input and transfer IC's, and combined power IC's. The semiconductor device includes a vertical bipolar transistor in which a base is electrically connected to an emitter and a collector, and a lateral MOSFET including a drain electrode connected to a surface electrode. The vertical bipolar transistor absorbs electrostatic discharge or surge energy when a high electrostatic discharge voltage or a high surge voltage is applied and limits the electrostatic discharge voltage or the surge voltage to be lower than the breakdown voltage of the lateral MOSFET.
    Type: Application
    Filed: May 21, 2003
    Publication date: February 12, 2004
    Inventors: Kazuhiko Yoshida, Takeshi Ichimura, Tatsuhiko Fujihira, Naoki Kumagai
  • Patent number: 6683347
    Abstract: A semiconductor device having an alternating conductivity type layer improves the tradeoff between the on-resistance and the breakdown voltage and facilitates increasing the current capacity by reducing the on- resistance while maintaining a high breakdown voltage. The semiconductor device includes a semiconductive substrate region, through which a current flows in the ON-state of the device and that is depleted in the OFF-state. The semiconductive substrate region includes a plurality of vertical alignments of n-type buried regions 32 and a plurality of vertical alignments of p-type buried regions. The vertically aligned n-type buried regions and the vertically aligned p-type buried regions are alternately arranged horizontally. The n-type buried regions and p-type buried regions are formed by diffusing respective impurities into highly resistive n-type layers 32a laminated one by one epitaxially.
    Type: Grant
    Filed: July 7, 1999
    Date of Patent: January 27, 2004
    Assignee: Fuji Electric Co., Ltd.
    Inventor: Tatsuhiko Fujihira
  • 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: 6677626
    Abstract: This invention achieves a high inverse voltage of a super-junction semiconductor device, which has a drift layer composed of a parallel pn layer that conducts electricity in the ON state and is depleted in the OFF state. An n− high resistance region is formed at the periphery of a drift layer composed of a parallel pn layer of n drift regions and p partition regions. The impurity density ND of the n− high resistance region is 5.62×1017×VDSS−1.36(cm−3) or less. VDSS denotes the withstand voltage (V). An n low resistance region is arranged adjacent to the n− high resistance region.
    Type: Grant
    Filed: November 10, 1999
    Date of Patent: January 13, 2004
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Youichi Shindou, Yasushi Miyasaka, Tatsuhiko Fujihira, Manabu Takei
  • Patent number: 6673679
    Abstract: A semiconductor device has an alternating conductivity type layer that improves the tradeoff relation between the ON-resistance and the breakdown voltage and a method of manufacturing such a semiconductor device. The alternating conductivity type layer is formed of n-type drift regions and p-type partition regions alternately arranged with each other. At least the n-type drift regions or p-type partition regions are formed by ion implantation under an acceleration voltage changed continuously. The p-type partition regions or n-type drift regions are formed by epitaxial growth or by diffusing impurities from the surface of a substrate or a layer for the layer.
    Type: Grant
    Filed: January 11, 2000
    Date of Patent: January 6, 2004
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Yasushi Miyasaka, Tatsuhiko Fujihira
  • 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: 20030211694
    Abstract: A semiconductor device is provided which can be manufactured even by using an inexpensive FZ wafer in a wafer process and still has a sharp inclination of a high impurity concentration in a high impurity concentration layer at the outermost portion of the reverse side and at the boundary between the high impurity concentration and a low impurity concentration drift layer, thus achieving both low cost and a high performance. A method for manufacturing a semiconductor device is also provided which can form a high impurity concentration buffer layer and a high impurity concentration layer at the outermost portion of the reverse side without any significant trouble, even after the formation of an active region and an electrode thereof at the right side, to thereby achieve both low cost and high performance.
    Type: Application
    Filed: June 13, 2003
    Publication date: November 13, 2003
    Applicant: Fuji Electric, Co., Ltd.
    Inventors: Manabu Takei, Tatsuhiko Fujihira