Patents by Inventor Toshiaki Iwamatsu

Toshiaki Iwamatsu 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: 6495898
    Abstract: In a combined isolation oxide film (BT1), a part closer to a gate electrode (GT13) reaches a buried oxide film (2) through an SOI layer (3) while a part closer to another gate electrode (GT12) has a sectional shape provided with a well region on its lower portion. The shape of an edge portion of the combined isolation oxide film (BT1) is in the form of a bird's beak in a LOCOS isolation oxide film. Consequently, the thicknesses of portions defining edge portions of the gate oxide films (GO12, GO13) are locally increased. Thus provided are a semiconductor device including a MOS transistor having a gate oxide film prevented from dielectric breakdown without increasing its thickness and a method of manufacturing the same.
    Type: Grant
    Filed: August 17, 2000
    Date of Patent: December 17, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Toshiaki Iwamatsu, Takashi Ipposhi, Takuji Matsumoto
  • Publication number: 20020171120
    Abstract: A semiconductor device with a spiral inductor is provided, which determines the area of an insulation layer to be provided in the surface of a wiring board thereunder. A trench isolation oxide film (19), which is a complete isolation oxide film including in part the structure of a partial isolation oxide film, is provided in a larger area of the surface of an SOI layer (3) than that corresponding to the area of a spiral inductor (SI). The trench isolation oxide film (19) is comprised of a first portion (191) having a first width and extending in a direction approximately perpendicular the surface of a buried oxide film (2), and a second portion (192) having a second width smaller than the first width and being continuously formed under the first portion (191), extending approximately perpendicular to the surface of the buried oxide film (2).
    Type: Application
    Filed: June 7, 2002
    Publication date: November 21, 2002
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventors: Shigenobu Maeda, Shigeto Maegawa, Takashi Ipposhi, Toshiaki Iwamatsu
  • Patent number: 6479330
    Abstract: At an edge portion of an FS gate electrode (10) beneath a side wall oxide film (106), an FS gate oxide film (101) is thicker. Relative to a surface of a silicon substrate (SB) beneath the FS gate oxide film (101), other surface of the silicon substrate (SB) is retracted. Thus, a MOS transistor with field-shield isolation structure and a method for manufacturing the same can be provided with higher reliability of the gate oxide film.
    Type: Grant
    Filed: August 7, 2001
    Date of Patent: November 12, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Toshiaki Iwamatsu, Takashi Ipposhi
  • Patent number: 6465292
    Abstract: An SOI layer is formed on a silicon substrate with a buried insulating layer therebetween. An SOI-MOSFET is formed including a drain region and a source region that are formed to define a channel formation region at the SOI layer and including a gate electrode layer opposite to the channel formation region with an insulating layer therebetween. An FS isolation structure is formed to have an FS plate opposite to a region of the SOI layer in the vicinity of the edge portion of the drain region and the source region, and to electrically isolate the SOI-MOSFET from other elements by applying a prescribed potential to the FS plate to fix the potential of the region of the SOI layer opposite to the FS plate. The channel formation region includes two edge portions on both sides and a central portion between the edge portions in a direction of a channel width, and a channel length at the edge of a prescribed region is smaller than a channel length at the central portion.
    Type: Grant
    Filed: February 4, 2002
    Date of Patent: October 15, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shigenobu Maeda, Yasuo Yamaguchi, Toshiaki Iwamatsu
  • Patent number: 6461935
    Abstract: A semiconductor device having a trench-shaped isolator, adjacent to the semiconductor element region is formed having a width which is continuously decreased in the downward direction for relaxing the stress in the silicon layer. Embodiments include forming a patterned dielectric layer on an SOI substrate, forming sidewall spacers thereon, and etching the underlying silicon layer followed by oxidation or controlled etching to form the trench with downwardly decreasing side surfaces.
    Type: Grant
    Filed: November 21, 2001
    Date of Patent: October 8, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shoichi Miyamoto, Toshiaki Iwamatsu, Takashi Ipposhi
  • Patent number: 6462428
    Abstract: A resist pattern (51) is formed only on buried silicon oxide films (2) on the whole surface of an alignment mark area (11A) and a trench (10C). With the resist pattern (51), preetching is performed by dry etching, to remove the silicon oxide film (2) on the whole of a memory cell area (11B) and part of a peripheral circuit area (11C) by a predetermined thickness. After removing the resist pattern (51), a silicon oxide film (3) and a silicon nitride film (4) are removed by CMP polishing, to provide a height difference between the highest portion and the lowest portion of the silicon oxide film (2A) which serves as an alignment mark. Thus, a semiconductor device with trench isolation structure which achieves a highly accurate alignment without deterioration of device performance and a method for manufacturing the semiconductor device can be provided.
    Type: Grant
    Filed: August 15, 2001
    Date of Patent: October 8, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Toshiaki Iwamatsu
  • Patent number: 6455894
    Abstract: Provided are a semiconductor device capable of satisfactorily solving a floating-body problem and a hot carrier problem which often arise in an SOI device and of causing a widely distributed partial isolating film to generate a crystal defect for peripheral structures with difficulty and a method of manufacturing the semiconductor device. A dummy region DM1 having no function as an element is formed at almost regular intervals in a partial isolating film 5b provided between MOS transistors TR1. Consequently, the occupation rate of the dummy region DM1 having a lower resistance value than that of a silicon layer 3b provided under the partial isolating film 5b is increased so that the floating-body problem and the hot carrier problem can be solved.
    Type: Grant
    Filed: October 3, 2000
    Date of Patent: September 24, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Takuji Matsumoto, Toshiaki Iwamatsu, Yuuichi Hirano
  • Publication number: 20020123205
    Abstract: In a combined isolation oxide film (BT1), a part closer to a gate electrode (GT13) reaches a buried oxide film (2) through an SOI layer (3) while a part closer to another gate electrode (GT12) has a sectional shape provided with a well region on its lower portion. The shape of an edge portion of the combined isolation oxide film (BT1) is in the form of a bird's beak in a LOCOS isolation oxide film. Consequently, the thicknesses of portions defining edge portions of the gate oxide films (GO12, GO13) are locally increased. Thus provided are a semiconductor device including a MOS transistor having a gate oxide film prevented from dielectric breakdown without increasing its thickness and a method of manufacturing the same.
    Type: Application
    Filed: April 16, 2002
    Publication date: September 5, 2002
    Inventors: Toshiaki Iwamatsu, Takashi Ipposhi, Takuji Matsumoto
  • Publication number: 20020110989
    Abstract: A partial oxide film (31) with well regions formed therebeneath isolates transistor formation regions in an SOI layer (3) from each other. A p-type well region (11) is formed beneath part of the partial oxide film (31) which isolates NMOS transistors from each other, and an n-type well region (12) is formed beneath part of the partial oxide film (31) which isolates PMOS transistors from each other. The p-type well region (11) and the n-type well region (12) are formed in side-by-side relation beneath part of the partial oxide film (31) which provides isolation between the NMOS and PMOS transistors. A body region is in contact with the well region (11) adjacent thereto. An interconnect layer formed on an interlayer insulation film (4) is electrically connected to the body region through a body contact provided in the interlayer insulation film (4). A semiconductor device having an SOI structure reduces a floating-substrate effect.
    Type: Application
    Filed: April 12, 2002
    Publication date: August 15, 2002
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventors: Yasuo Yamaguchi, Shigeto Maegawa, Takashi Ipposhi, Toshiaki Iwamatsu, Shigenobu Maeda, Yuuichi Hirano, Takuji Matsumoto, Shoichi Miyamoto
  • Publication number: 20020109187
    Abstract: It is an object to provide a semiconductor device having an SOI structure in which an electric potential of a body region in an element formation region isolated by a partial isolation region can be fixed with a high stability. A MOS transistor comprising a source region (51), a drain region (61) and an H gate electrode (71) is formed in an element formation region isolated by a partial oxide film (31). The H gate electrode (71) electrically isolates a body region (13) formed in a gate width W direction adjacently to the source region (51) and the drain region (61) from the drain region (61) and the source region (51) through “I” in a transverse direction (a vertical direction in the drawing), a central “-” functions as a gate electrode of an original MOS transistor.
    Type: Application
    Filed: November 7, 2001
    Publication date: August 15, 2002
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventors: Takuji Matsumoto, Shigenobu Maeda, Toshiaki Iwamatsu, Takashi Ipposhi
  • Publication number: 20020105031
    Abstract: According to a semiconductor device of the present invention, a field oxide film is formed so as to cover the main surface of an SOI layer and to reach the main surface of a buried oxide film. As a result, a pMOS active region of the SOI and an nMOS active region of the SOI can be electrically isolated completely. Therefore, latchup can be prevented completely. As a result, it is possible to provide a semiconductor device using an SOI substrate which can implement high integration by eliminating reduction of the breakdown voltage between source and drain, which was a problem of a conventional SOI field effect transistor, as well as by efficiently disposing a body contact region, which hampers high integration, and a method of manufacturing the same.
    Type: Application
    Filed: February 5, 2002
    Publication date: August 8, 2002
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventors: Yasuo Inoue, Tadashi Nishimura, Yasuo Yamaguchi, Toshiaki Iwamatsu
  • Publication number: 20020100939
    Abstract: In a combined isolation oxide film (BT1), a part closer to a gate electrode (GT13) reaches a buried oxide film (2) through an SOI layer (3) while a part closer to another gate electrode (GT12) has a sectional shape provided with a well region on its lower portion. The shape of an edge portion of the combined isolation oxide film (BT1) is in the form of a bird's beak in a LOCOS isolation oxide film. Consequently, the thicknesses of portions defining edge portions of the gate oxide films (GO12, GO13) are locally increased. Thus provided are a semiconductor device including a MOS transistor having a gate oxide film prevented from dielectric breakdown without increasing its thickness and a method of manufacturing the same.
    Type: Application
    Filed: March 6, 2002
    Publication date: August 1, 2002
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventors: Toshiaki Iwamatsu, Takashi Ipposhi, Takuji Matsumoto
  • Patent number: 6426543
    Abstract: A semiconductor device with a spiral inductor is provided, which determines the area of an insulation layer to be provided in the surface of a wiring board thereunder. A trench isolation oxide film, which is a complete isolation oxide film including in part the structure of a partial isolation oxide film, is provided in a larger area of the surface of an SOI layer than that corresponding to the area of a spiral inductor. The trench isolation oxide film includes a first portion having a first width and extending in a direction approximately perpendicular the surface of a buried oxide film, and a second portion having a second width smaller than the first width and being continuously formed under the first portion, extending approximately perpendicular to the surface of the buried oxide film. The trench isolation oxide film is provided such that a horizontal distance between each end surface of the second portion and a corresponding end surface of the spiral inductor makes a predetermined distance or more.
    Type: Grant
    Filed: November 22, 2000
    Date of Patent: July 30, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shigenobu Maeda, Shigeto Maegawa, Takashi Ipposhi, Toshiaki Iwamatsu
  • Patent number: 6424010
    Abstract: An SOI layer is formed on a silicon substrate with a buried insulating layer therebetween. An SOI-MOSFET is formed including a drain region and a source region that are formed to define a channel formation region at the SOI layer and including a gate electrode layer opposite to the channel formation region with an insulating layer therebetween. A field-shield (FS) isolation structure is formed to have an FS plate opposite to a region of the SOI layer in the vicinity of the edge portion of the drain region and the source region, and to electrically isolate the SOI-MOSFET from other elements by applying a prescribed potential to the FS plate to fix the potential of the region of the SOI layer opposite to the FS plate. The channel formation region includes the edge portions on both sides and a central portion between the edge portions in a direction of a channel width, and a channel length at the edge of prescribed region is smaller than a channel length at the central portion.
    Type: Grant
    Filed: October 9, 1998
    Date of Patent: July 23, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shigenobu Maeda, Yasuo Yamaguchi, Toshiaki Iwamatsu
  • Publication number: 20020094614
    Abstract: An SOI layer is formed on a silicon substrate with a buried insulating layer therebetween. An SOI-MOSFET is formed including a drain region and a source region that are formed to define a channel formation region at the SOI layer and including a gate electrode layer opposite to the channel formation region with an insulating layer therebetween. An FS isolation structure is formed to have an FS plate opposite to a region of the SOI layer in the vicinity of the edge portion of the drain region and the source region, and to electrically isolate the SOI-MOSFET from other elements by applying a prescribed potential to the FS plate to fix the potential of the region of the SOI layer opposite to the FS plate. The channel formation region includes two edge portions on both sides and a central portion between the edge portions in a direction of a channel width, and a channel length at the edge of a prescribed region is smaller than a channel length at the central portion.
    Type: Application
    Filed: February 4, 2002
    Publication date: July 18, 2002
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventors: Shigenobu Maeda, Yasuo Yamaguchi, Toshiaki Iwamatsu
  • Publication number: 20020090764
    Abstract: In formation of a source/drain region of an NMOS transistor, a gate-directional extension region <41a> of an N+ block region <41> in an N+ block resist film <51> prevents a well region <11> located under the gate-directional extension region <41a> from implantation of an N-type impurity. A high resistance forming region, which is the well region <11> having a possibility for implantation of an N-type impurity on a longitudinal extension of a gate electrode <9>, can be formed as a high resistance forming region <A2> narrower than a conventional high resistance forming region <A1>. Thus, a semiconductor device having a partially isolated body fixed SOI structure capable of reducing body resistance and a method of manufacturing the same are obtained.
    Type: Application
    Filed: November 20, 2001
    Publication date: July 11, 2002
    Applicant: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shigenobu Maeda, Toshiaki Iwamatsu, Takashi Ipposhi
  • Patent number: 6410973
    Abstract: A semiconductor integrated circuit is formed by MESA isolation of a thin film silicon layer, in which transistor characteristics are free from influence depending on pattern density of transistor forming regions. The thin film silicon layer on an insulating substrate is isolated by MESA isolation, and element forming regions are formed. In the middle part of a large distance between adjacent element forming regions, a LOCOS oxide film is thickly formed, and an oxide film is buried between the LOCOS oxide film and the element forming regions contiguously at the same surface level so that there is no step-like level difference therebetween.
    Type: Grant
    Filed: June 24, 1999
    Date of Patent: June 25, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Toshiaki Iwamatsu, Takashi Ipposhi
  • Publication number: 20020060320
    Abstract: To provide a semiconductor device capable of preventing drawbacks from being caused by metal pollution and a method of manufacturing the semiconductor device. A region (NR) and a region (PR) are defined by a trench isolation oxide film (ST21), a polysilicon film (PS21) is selectively provided on the trench isolation oxide film (ST21), a silicon layer (S22) is provided on the polysilicon film (PS21), and a side wall spacer (SW2) is provided on a side surface of the polysilicon film (PS21). The polysilicon film (PS21) is provided in a position corresponding to a top of a PN junction portion JP of a P-type well region (WR11) and an N-type well region (WR12) in an SOI layer 3 across the two well regions.
    Type: Application
    Filed: November 1, 2001
    Publication date: May 23, 2002
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventors: Toshiaki Iwamatsu, Takashi Ipposhi, Hideki Naruoka, Nobuyoshi Hattori, Shigeto Maegawa, Yasuo Yamaguchi, Takuji Matsumoto
  • Patent number: 6383860
    Abstract: A first impurity diffusion layer forms one of source/drain regions and also forms a bit line. A first semiconductor layer, a channel semiconductor layer and a second semiconductor layer, which forms the other of source/drain regions and also forms a storage node, are disposed on the first impurity diffusion layer. A capacitor insulating film is disposed on a second conductive layer. A cell plate is disposed on a storage node with the capacitor insulating film therebetween. A capacitance of the bit line is reduced, and a dynamic random access memory thus constructed performs a high-speed operation.
    Type: Grant
    Filed: July 20, 2001
    Date of Patent: May 7, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shigenobu Maeda, Yasuo Inoue, Hirotada Kuriyama, Shigeto Maegawa, Kyozo Kanamoto, Toshiaki Iwamatsu
  • Publication number: 20020052066
    Abstract: An SOI layer is thinned without a thermal oxidation process. An SOI substrate (10) is immersed in an etching bath filled with an NH3—H2O2—H2O solution to be isotropically etched. This produces a 100-nm thick SOI layer (3) with no crystal defect.
    Type: Application
    Filed: May 13, 1999
    Publication date: May 2, 2002
    Inventors: TAKASHI IPPOSHI, TOSHIAKI IWAMATSU