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: 6380089
    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-mn thick SOI layer (3) with no crystal defect.
    Type: Grant
    Filed: May 13, 1999
    Date of Patent: April 30, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Takashi Ipposhi, Toshiaki Iwamatsu
  • Publication number: 20020048919
    Abstract: A semiconductor device in which parasitic resistance of source/drain regions can be reduced than the parasitic resistance of the drain region, and manufacturing method thereof, can be obtained. In the semiconductor device, inactivating ions are implanted only to the source region of the semiconductor layer, so as to damage the crystal near the surface of the semiconductor layer, whereby siliciding reaction is promoted. Therefore, in the source region, a titanium silicide film which is thicker can be formed.
    Type: Application
    Filed: October 22, 2001
    Publication date: April 25, 2002
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventors: Toshiaki Iwamatsu, Yasuo Inoue, Yasuo Yamaguchi, Tadashi Nishimura
  • Patent number: 6372599
    Abstract: The invention provides a semiconductor device having the trench-shaped isolator is provided with a portion which is adjacent to the semiconductor element region, of which the width is continuously decreased in the downward direction, and of which the surface is planarized near the semiconductor element region, for relaxing the stress in the silicon layer and being flat the surface of the trench-shaped insulator, and method of manufacturing the same.
    Type: Grant
    Filed: August 10, 1999
    Date of Patent: April 16, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shoichi Miyamoto, Toshiaki Iwamatsu, Takashi Ipposhi
  • Publication number: 20020031881
    Abstract: The invention provides a semiconductor device having the trench-shaped isolator is provided with a portion which is adjacent to the semiconductor element region, of which the width is continuously decreased in the downward direction, and of which the surface is planarized near the semiconductor element region, for relaxing the stress in the silicon layer and being flat the surface of the trench-shaped insulator, and method of manufacturing the same.
    Type: Application
    Filed: November 21, 2001
    Publication date: March 14, 2002
    Applicant: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shoichi Miyamoto, Toshiaki Iwamatsu, Takashi Ipposhi
  • Patent number: 6351014
    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: Grant
    Filed: March 6, 2000
    Date of Patent: February 26, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yasuo Inoue, Tadashi Nishimura, Yasuo Yamaguchi, Toshiaki Iwamatsu
  • Publication number: 20020014663
    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 the 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: Application
    Filed: June 24, 1999
    Publication date: February 7, 2002
    Inventors: TOSHIAKI IWAMATSU, TAKASHI IPPOSHI
  • Publication number: 20020016025
    Abstract: A sidewall oxide layer and a sidewall insulation layer are formed to cover the edge portion of an SOI layer. A channel stopper region is formed in the vicinity of the edge portion of the SOI layer. A protruded insulation layer is formed on the channel stopper region. A gate electrode extends from a region over the SOI layer to the protruded insulation layer and the sidewall insulation layer. In this way, reduction in threshold voltage Vth of a parasitic MOS transistor at the edge portion of the SOI layer can be suppressed.
    Type: Application
    Filed: January 12, 2000
    Publication date: February 7, 2002
    Inventors: Takashi Ipposhi, Toshiaki Iwamatsu, Yasuo Yamaguchi
  • Publication number: 20020009837
    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: Application
    Filed: August 7, 2001
    Publication date: January 24, 2002
    Applicant: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Toshiaki Iwamatsu, Takashi Ipposhi
  • Publication number: 20020005594
    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: Application
    Filed: August 15, 2001
    Publication date: January 17, 2002
    Applicant: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Toshiaki Iwamatsu
  • Publication number: 20020005552
    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: March 6, 2000
    Publication date: January 17, 2002
    Inventors: Yasuo Inoue, Tadashi Nishimura, Yasuo Yamaguchi, Toshiaki Iwamatsu
  • Patent number: 6335267
    Abstract: A semiconductor substrate and a method of fabricating a semiconductor device are provided. An oxide film (13) is formed by oxidizing an edge section and a lower major surface of an SOI substrate (10). This oxidizing step is performed in a manner similar to LOCOS (Local Oxide of Silicon) oxidation by using an oxide film (11) exposed on the edge section and lower major surface of the SOI substrate (10) as an underlying oxide film. Then, the thickness of the oxide film (13) is greater than that of the oxide film (11) on the edge section and lower major surface of the SOI substrate (10). The semiconductor substrate prevents particles of dust from being produced at the edge thereof.
    Type: Grant
    Filed: September 22, 2000
    Date of Patent: January 1, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Toshiaki Iwamatsu, Yasuo Yamaguchi, Takashi Ipposhi, Shigenobu Maeda, Yuichi Hirano
  • Publication number: 20010052620
    Abstract: Formed on an insulator (9) are an N− type semiconductor layer (10) having a partial isolator formed on its surface and a P− type semiconductor layer (20) having a partial isolator formed on its surface. Source/drain (11, 12) being P+ type semiconductor layers are provided on the semiconductor layer (10) to form a PMOS transistor (1). Source/drain (21, 22) being N+ type semiconductor layers are provided on the semiconductor layer (20) to form an NMOS transistor (2). A pn junction (J5) formed by the semiconductor layers (10, 20) is provided in a CMOS transistor (100) made up of the transistors (1, 2). The pn junction (J5) is positioned separately from the partial isolators (41, 42), where the crystal defect is thus very small. Therefore, the leakage current is very low at the pn junction (J5).
    Type: Application
    Filed: March 22, 2001
    Publication date: December 20, 2001
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventors: Takashi Ipposhi, Toshiaki Iwamatsu
  • Publication number: 20010050397
    Abstract: A silicon nitride film is formed between interlayer insulating films covering an upper surface of an element formed on a surface of a semiconductor layer. With this structure, a semiconductor device comprising an isolation insulating film of PTI structure, which suppresses a floating-body effect and improves isolation performance and breakdown voltage, and a method of manufacturing the semiconductor device can be obtained.
    Type: Application
    Filed: December 6, 2000
    Publication date: December 13, 2001
    Inventors: Takuji Matsumoto, Toshiaki Iwamatsu, Yuuichi Hirano
  • Publication number: 20010045601
    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: October 9, 1998
    Publication date: November 29, 2001
    Inventors: SHIGENOBU MAEDA, YASUO YAMAGUCHI, TOSHIAKI IWAMATSU
  • Patent number: 6323527
    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: April 6, 1998
    Date of Patent: November 27, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Toshiaki Iwamatsu, Takashi Ipposhi
  • Patent number: 6319805
    Abstract: A semiconductor device in which parasitic resistance of source/drain regions can be reduced than the parasitic resistance of the drain region, and manufacturing method thereof, can be obtained. In the semiconductor device, inactivating ions are implanted only to the source region of the semiconductor layer, so as to damage the crystal near the surface of the semiconductor layer, whereby siliciding reaction is promoted. Therefore, in the source region, a titanium silicide film which is thicker can be formed.
    Type: Grant
    Filed: February 8, 2000
    Date of Patent: November 20, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Toshiaki Iwamatsu, Yasuo Inoue, Yasuo Yamaguchi, Tadashi Nishimura
  • Publication number: 20010041438
    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: Application
    Filed: July 20, 2001
    Publication date: November 15, 2001
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventors: Shigenobu Maeda, Yasuo Inoue, Hirotada Kuriyama, Shigeto Maegawa, Kyozo Kanamoto, Toshiaki Iwamatsu
  • Patent number: 6303425
    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: September 12, 2000
    Date of Patent: October 16, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shigenobu Maeda, Yasuo Inoue, Hirotada Kuriyama, Shigeto Maegawa, Kyozo Kanamoto, Toshiaki Iwamatsu
  • Patent number: 6303460
    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: February 7, 2000
    Date of Patent: October 16, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Toshiaki Iwamatsu
  • Publication number: 20010025990
    Abstract: An isolation insulating film (5) of partial-trench type is selectively formed in an upper surface of a silicon layer (4). A power supply line (21) is formed above the isolation insulating film (5). Below the power supply line (21), a complete isolation portion (23) reaching an upper surface of an insulating film (3) is formed in the isolation insulating film (5). In other words, a semiconductor device comprises a complete-isolation insulating film which is so formed as to extend from the upper surface of the silicon layer (4) and reach the upper surface of insulating film (3) below the power supply line (21). With this structure, it is possible to obtain the semiconductor device capable of suppressing variation in potential of a body region caused by variation in potential of the power supply line.
    Type: Application
    Filed: March 12, 2001
    Publication date: October 4, 2001
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventors: Yuuichi Hirano, Shigeto Maegawa, Toshiaki Iwamatsu, Takuji Matsumoto, Shigenobu Maeda, Yasuo Yamaguchi