Patents by Inventor Masakazu Kakumu

Masakazu Kakumu 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: 20230145678
    Abstract: A dynamic flash memory is formed by stacking, on a first impurity layer on a P-layer substrate, a first insulating layer, a first material layer, a second insulating layer, a second material layer, a third insulating layer, a third material layer, and a fourth material layer, forming a first hole penetrating these layers on the P-layer substrate, forming a semiconductor pillar by embedding the first hole with a semiconductor, removing the first, second, and third material layers to form second, third, and fourth holes, by oxidizing an outermost surface of the semiconductor pillar exposing in the second, third, and fourth holes to form first, second, and third gate insulating layers, and forming first, second, and third gate conductor layers embedded in the second, third, and fourth holes.
    Type: Application
    Filed: November 7, 2022
    Publication date: May 11, 2023
    Inventors: Riichiro SHIROTA, Nozomu HARADA, Koji SAKUI, Masakazu KAKUMU
  • Publication number: 20230115447
    Abstract: A groove is formed in a first semiconductor layer 1, a sidewall of the groove is coated with a first insulating film 2, a first impurity layer 3 and a second impurity layer 4 thereon are disposed in the groove, a second semiconductor layer 7 is disposed on the second impurity layer, a first semiconductor is disposed at the other part, an n+ layer 6a and an n+ layer 6c are positioned at respective ends of the second semiconductor layer 7 and connected to a source line SL and a bit line BL, respectively, a first gate insulating layer 8 is formed on the second semiconductor layer 7, and a first gate conductor layer 9 is connected to a word line WL.
    Type: Application
    Filed: September 6, 2022
    Publication date: April 13, 2023
    Inventors: Masakazu KAKUMU, Koji SAKUI, Nozomu HARADA
  • Publication number: 20230108227
    Abstract: First and second impurity layers are formed on a first semiconductor layer on a substrate. A third gate insulating layer covers side walls of the impurity layers and the first semiconductor layer. First and second gate conductor layers and a second insulating layer are formed in a groove, and n+-layers connected to source and bit lines are formed at ends of a second semiconductor layer formed on the second impurity layer and covered with a second gate insulating layer, on which a third gate conductor layer connected to a word line is formed. An operation of maintaining holes generated in a channel region of the second semiconductor layer by impact ionization or a GIDL current near the gate insulating layer and an operation of discharging the holes from the channel region are performed by controlling voltages applied to the source, bit, and word lines and first and second plate lines.
    Type: Application
    Filed: October 5, 2022
    Publication date: April 6, 2023
    Inventors: Masakazu KAKUMU, Koji SAKUI, Nozomu HARADA
  • Publication number: 20230077140
    Abstract: A first semiconductor layer 1 is formed on a substrate, a first impurity layer 3 and a second impurity layer 4 extending in a vertical direction are sequentially disposed on part of the first semiconductor layer 1, their sidewalls and the semiconductor layer 1 are covered by a second gate insulating layer 2, a gate conductor layer 22 and a second insulating layer are disposed in a groove formed there, and a second semiconductor layer 7, n+ layers 6a and 6c positioned at respective ends of the layer 7 and connected to a source line SL and a bit line BL, respectively, a second gate insulating layer 8 formed to cover the second semiconductor layer 7, and a second gate conductor layer 9 connected to a word line WL are disposed on the second impurity layer.
    Type: Application
    Filed: September 2, 2022
    Publication date: March 9, 2023
    Inventors: Masakazu KAKUMU, Koji SAKUI, Nozomu HARADA
  • Publication number: 20230046352
    Abstract: Material layers including first and second poly-Si layer are formed on a P-layer substrate. Holes which are parallel to each other and each of which is continuous in a first direction are formed in the material layers. The first and second poly-Si layers are each divided by the holes in a second direction orthogonal to the first direction in plan view. Gate insulating layers and P-layer Si pillars are formed in the holes. The P-layer Si pillars are isolated from one another by the gate insulating layers. A dynamic flash memory is formed in which a first gate conductor layer is connected to a plate line, a second gate conductor layer is connected to a word line, the P-layer Si pillars serve as channels, and one of the N+ layers below and above the P-layer Si pillars is connected to a source line.
    Type: Application
    Filed: August 9, 2022
    Publication date: February 16, 2023
    Inventors: Nozomu HARADA, Koji SAKUI, Masakazu KAKUMU
  • Publication number: 20230039991
    Abstract: An n+ layer 3a connected to a source line SL at both ends, an n+ layer 3b connected to a bit line BL, a first gate insulating layer 4a formed on a semiconductor substrate 1 existing on an insulating film 2, a gate conductor layer 16a connected to a plate line PL, a gate insulating layer 4b formed on the semiconductor substrate, and a second gate conductor layer 5b connected to a word line WL and having a work function different from a work function of the gate conductor layer 16a are disposed on the semiconductor substrate, and data hold operation of holding, near a gate insulating film, holes generated by an impact ionization phenomenon or gate-induced drain leakage current inside a channel region 12 of the semiconductor substrate 1 and data erase operation of removing the holes from inside the substrate 1 and the channel region 12 are performed by controlling voltage applied to the source line SL, the plate line PL, the word line WL, and the bit line BL.
    Type: Application
    Filed: August 1, 2022
    Publication date: February 9, 2023
    Inventors: Masakazu KAKUMU, Koji SAKUI, Nozomu HARADA
  • Patent number: 5847412
    Abstract: A plurality of silicon insulating films are formed to separate regions to be formed with elements from each other on a silicon semiconductor substrate. Silicon layers are formed by an epitaxially growing method on the regions to be formed with the elements and the silicon insulating film. An MOS transistor is formed on the monocrystalline silicon layer formed on the regions to be formed with the elements of the silicon layer, and the polysilicon layer formed on the silicon insulating film is used as a high resistance element or doped with an impurity as a conductor line.
    Type: Grant
    Filed: June 3, 1997
    Date of Patent: December 8, 1998
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masakazu Kakumu, Masaaki Kinugawa
  • Patent number: 5756365
    Abstract: In a semiconductor device, an n.sup.+ -type polysilicon layer is formed on a substrate through a gate oxide layer. A p.sup.+ -type source or drain diffusion layer is formed on both sides of an impurity layer in the substrate. The n.sup.+ -type polysilicon layer is positioned over an intermediate portion of a channel formation layer, and has an oxide layer on an upper surface thereof. The n.sup.+ -type polysilicon layer has at its side portions a p.sup.+ -type polysilicon layer to make a gate electrode together with the n.sup.+ -type polysilicon layer. The gate electrode semiconductor layer is formed on the channel formation layer through the gate insulation layer in such a manner that in a portion contacting with the gate insulation layer, the nearer the portion approaches the impurity layers of the source and drain regions, the larger the work function of the portion becomes.
    Type: Grant
    Filed: September 25, 1996
    Date of Patent: May 26, 1998
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Masakazu Kakumu
  • Patent number: 5654241
    Abstract: In a method for manufacturing a semiconductor device, metal ions are doped into the surface regions of diffusion layers or a diffusion layer forming region, thereby forming metal silicide layers of low resistance on only the diffusion layers. In a further method for manufacturing a semiconductor device, metal ions are doped into the surface regions of diffusion layers or a diffusion layer forming region and the upper surface of a gate electrode. Then, the structure is subjected to a process to make a silicide, thereby forming metal silicide layers of low resistance on only the diffusion layers and the gate electrode.
    Type: Grant
    Filed: December 21, 1989
    Date of Patent: August 5, 1997
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Masakazu Kakumu
  • Patent number: 5592010
    Abstract: A semiconductor device comprising a main circuit having a p-channel MOSFET formed on the surface off the substrate and an n-channel MOSFET formed on the p-type well region which is formed on the n-type Si substrate chip), an input/output (I/O) circuit formed on the substrate, and a substrate bias generating circuit formed on the substrate, characterized by controlling the substrate bias generating circuit via the I/O circuit, and varying a bias supplied to the substrate and the p-type well region, in accordance with the operation mode of the main circuit.
    Type: Grant
    Filed: November 22, 1994
    Date of Patent: January 7, 1997
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masakazu Kakumu, Kazutaka Nogami, Yuki Satoh
  • Patent number: 5489795
    Abstract: A semiconductor device has a first P type well region (11) formed on an N type semiconductor substrate (10) and a second N type well region (12) formed so as to enclose the first well region. A third N type well region (13) formed on the semiconductor substrate is enclosed by a fourth P type well region (14). The first well region adjoins and is electrically connected to the fourth well region. Contact regions (15, 16) are formed on the first and third well regions to apply a bias voltage to the PN junction between the first and third well regions. An NMOS FET is formed in the first well region and a PMOS FET is formed in the third well region. The drain currents of the NMOS FET and PMOS FET are controlled by changing the reverse bias voltage applied to the two contact regions (15, 16). The depth of the first well region (11) is such that a depletion layer extending below the NMOS FET gate electrode (50) can be connected to a depletion layer formed at an interface between the first and second well regions.
    Type: Grant
    Filed: October 4, 1994
    Date of Patent: February 6, 1996
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hisao Yoshimura, Takeo Maeda, Masakazu Kakumu
  • Patent number: 5466958
    Abstract: In a semiconductor device, an n.sup.+ polysilicon layer is formed on a substrate through a gateoxide layer. A p.sup.+ source or drain diffusion layer is formed on both sides of an impurity layer in the substrate. The silicon layer positions over an intermediate portion of a channel formation layer, and has an oxide layer on upper surface thereof. The silicon layers have their side portions a p.sup.+ type polysilicon layer to be a gate electrode together with the silicon layer. The gate electrode semiconductor layer is formed on the channel formation layer through the gate insulation layer in the manner that, in a portion contacting with the gate insulation layer, the nearer portions approaches to the impurity layers of the source and drain regions, the larger a work function increases.
    Type: Grant
    Filed: November 1, 1993
    Date of Patent: November 14, 1995
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Masakazu Kakumu
  • Patent number: 5300462
    Abstract: A method is disclosed for alloying a sputtered metal film by forming a sputtered metal film of first metal atoms over a semiconductor substrate through a first mask and implanting a first impurity of second metal atoms into the sputtered film. Then a second mask having at least one window is formed on the sputtered film by removing said first mask and a second impurity of third metal atoms is then implanted. The substrate and film are then heat treated to form a first alloy area in which the first metal atoms and the second metal atoms are mixed and a second alloy area in which the first metal atoms and the third metal atoms are mixed.
    Type: Grant
    Filed: July 8, 1992
    Date of Patent: April 5, 1994
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Masakazu Kakumu
  • Patent number: 5278430
    Abstract: A complementary semiconductor device incorporating semiconductor composed of diamond. Substantially, diamond is insulative. When both III group elementary atoms and V group elementary atoms are doped into diamond, the doped regions respectively turn into p-type and n-type semiconductors. The embodiment discretely dopes both III group elementary atoms and V group elementary atoms into a layer of diamond thin film to eventually form a complementary semiconductor device. The embodiment forms wiring system inside of the diamond thin film by selectively doping either III group elementary atoms or V group elementary atoms therein without forming wiring system only on the inter-layer insulation film.
    Type: Grant
    Filed: February 18, 1992
    Date of Patent: January 11, 1994
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Masakazu Kakumu
  • Patent number: 5073813
    Abstract: A MOS structure is formed on a silicon semiconductor substrate surface using a first gate electrode film made of polysilicon, an element isolation groove reaching the inside of the silicon semiconductor substrate is formed, and an insulating film is filled in the groove. In addition, a second gate electrode film made of a refractory metal such as molybdenum silicide is formed to be connected to the first gate electrode film, and the first and second gate electrode films are simultaneously removed to form a MOS gate electrode and a wiring layer.
    Type: Grant
    Filed: July 26, 1990
    Date of Patent: December 17, 1991
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Shigeru Morita, Kikuo Yamabe, Masakazu Kakumu
  • Patent number: 4812889
    Abstract: A semiconductor device comprises a semiconductor substrate of a first conductivity type, a first impurity region of second conductivity which is formed in the substrate, a second impurity region of the second conductivity type which is formed in the substrate and spaced apart from the first semiconductor region, a channel region located between the first and second impurity regions, an insulation layer on the channel region, and a gate electrode on the insulation layer including conductive layer means for decreasing the temperature dependence of the semiconductor device, the layer means including a conductive layer and a semiconductive layer for reducing energy level degeneration.
    Type: Grant
    Filed: September 16, 1986
    Date of Patent: March 14, 1989
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Masakazu Kakumu
  • Patent number: 4800176
    Abstract: A method of manufacturing semiconductor devices according to the present invention includes the steps of forming an element isolation region on the main surface of a semiconductor substrate of a first conductivity type, forming a high impurity concentration layer of a second conductivity type in the surface area of a portion of the semiconductor substrate defined by the element isolation region, and forming a first insulation film on the entire surface of the resultant semiconductor structure. Thereafter, a contact hole is formed in the first insulation film which is formed on the high impurity concentration layer, a semiconductor layer containing an impurity of the same conductivity type as the high impurity concentration layer is formed on the first insulation film, and a second insulation film is formed on the semiconductor layer.
    Type: Grant
    Filed: April 19, 1988
    Date of Patent: January 24, 1989
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masakazu Kakumu, Tetsuya Asami
  • Patent number: 4746625
    Abstract: A semiconductor manufacturing method which comprises the steps of forming a polycrystalline silicon layer on a semiconductor substrate; depositing a silicon oxide layer on the polycrystalline silicon layer; mounting an acidproof layer on the silicon oxide layer; selectively eliminating the acidproof layer deposited on a semiconductor element-isolating region by the photoetching process; selectively eliminating the silicon oxide layer with the retained acidproof layer used as a mask; ion implanting a channel stopper impurity in the semiconductor substrate through the masks formed of a photoresist coated on the acidproof layer the acidproof layer, and silicon oxide layer; eliminating the photoresist; selectively depositing a silicon layer on the exposed polycrystalline silicon; carrying out thermal oxidation with the acidproof layer used as a mask; eliminating the acidproof layer; filling an oxide in the cavities of the side walls of the semiconductor element-isolating insulation layer; and exposing by etching
    Type: Grant
    Filed: February 17, 1987
    Date of Patent: May 24, 1988
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Sigeru Morita, Masakazu Kakumu
  • Patent number: 4721687
    Abstract: A method of manufacturing a semiconductor substrate, and, in particular, a technique of electrically isolating a semiconductor element formed on a semiconductor substrate. The method comprises the steps of depositing a silicon oxide layer on the surface of a silicon substrate, for its protection; forming a silicon nitride layer on the silicon oxide layer; selectively eliminating the silicon nitride layer; oxidizing the silicon substrate, with the retained silicon nitride layer being used as a mask, thereby providing an oxide layer; depositing a polycrystalline silicon layer on the oxide layer and the retained acid-resisting layer; oxidizing the polycrystalline silicon layer to provide an insulation layer; eliminating the insulation layer until the silicon nitride layer is exposed; and removing all the silicon nitride layer.
    Type: Grant
    Filed: February 6, 1987
    Date of Patent: January 26, 1988
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masakazu Kakumu, Sigeru Morita
  • Patent number: 4536943
    Abstract: In a method of forming electrodes or wiring structures in a semiconductor device, metal and metal silicide are used for electrodes and lead wires, impurities are doped into the interface of a semiconductor substrate from the surface by gas diffusion or solid diffusion irrespective of the thickness, and in the case where the base material is an insulating material, the impurities are not doped into the semiconductor region side by self-alignment.
    Type: Grant
    Filed: May 20, 1983
    Date of Patent: August 27, 1985
    Assignee: Tokyo Shibaura Denki Kabushiki Kaisha
    Inventor: Masakazu Kakumu