Patents by Inventor Shinsuke Sadamitsu

Shinsuke Sadamitsu 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: 8252404
    Abstract: Disclosed are high resistivity silicon wafers, wherein the interstitial oxygen concentration thereof is 8×1017 atoms/cm3 (ASTM F121-1979) or less, BMD (Bulk Micro Defect) density—oxygen precipitate within wafer—is 5×107 pieces/cm3 or less, and an electric resistivity thereof is 100 ?·cm or more. And further disclosed are high resistivity silicon wafers having an electric resistivity of 100 ?·cm or more, which are cut from crystal region where no COP (Crystal Originated Particle) exist, and in which neither COP (Crystal Originated Particle) nor oxygen precipitate exist at the area from wafer surface to the depth of 5 ?m or more owing to high temperature treatment. It is preferable that, in said high resistivity wafers, carbon concentration in wafers is 1×1016 atoms/cm3 or more (ASTM F123-1981), and/or nitrogen concentration is 1×1013 atoms/cm3 or more.
    Type: Grant
    Filed: November 12, 2004
    Date of Patent: August 28, 2012
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventors: Shinsuke Sadamitsu, Masataka Hourai
  • Publication number: 20110171814
    Abstract: A method for preparing a silicon epitaxial wafer that includes a silicon single crystal wafer sliced from a CZ silicon ingot doped with carbon in a concentration range of not less than 5×1015 atoms/cm3 and not more than 5×1017 atoms/cm3 and an epitaxial layer consisting of a silicon single crystal epitaxially grown on a front surface of the silicon single crystal wafer. A polycrystalline silicon layer having a thickness of not less than 0.5 ?m and not more than 1.5 ?m is formed on a back surface of the silicon single crystal wafer.
    Type: Application
    Filed: March 18, 2011
    Publication date: July 14, 2011
    Applicant: SUMCO CORPORATION
    Inventors: Shinsuke Sadamitsu, Masataka Hourai
  • Patent number: 7803228
    Abstract: By using oxygen-containing silicon wafers obtained by the CZ method and by combining the first heat treatment comprising controlled heat-up operation (ramping) with the second heat treatment comprising high-temperature heat treatment and medium temperature heat treatment in accordance with the process for producing high-resistance silicon wafers according to the present invention, it is possible to obtain high-resistance silicon wafers capable of maintaining their high resistance even after heat treatment in the process of device manufacture while efficiently inhibiting the formation of oxygen donors and preventing changes in resistivity. Further, excellent epitaxial wafers and SOI wafers can be produced using those high-resistance silicon wafers and, therefore, they can be applied in a wide field including high-frequency communication devices and analog/digital hybrid devices, among others.
    Type: Grant
    Filed: August 2, 2004
    Date of Patent: September 28, 2010
    Assignee: Sumco Corporation
    Inventors: Kazunari Kurita, Shinsuke Sadamitsu, Hiroyuki Takao, Masataka Hourai
  • Patent number: 7700394
    Abstract: There is obtained a silicon wafer which has a large diameter, where no slip generated therein in a wide range of a density of oxygen precipitates even though a heat treatment such as SLA or FLA is applied thereto, and which has high strength. First, by inputting as input parameters combinations of a plurality of types of oxygen concentrations and thermal histories set for manufacture of a silicon wafer, a Fokker-Planck equation is solved to calculate each of a diagonal length L and a density D of oxygen precipitates in the wafer after a heat treatment step to form the oxygen precipitates (11) and immediately before a heat treatment step of a device manufacturing process is calculated.
    Type: Grant
    Filed: June 21, 2005
    Date of Patent: April 20, 2010
    Assignee: Sumco Corporation
    Inventors: Shinsuke Sadamitsu, Wataru Sugimura, Masanori Akatsuka, Masataka Hourai
  • Publication number: 20090017291
    Abstract: A silicon epitaxial wafer of the invention comprises a silicon single crystal wafer sliced from a CZ silicon ingot doped with carbon in a concentration range of not less than 5×1015 atoms/cm3 and not more than 5×1017 atoms/cm3 and an epitaxial layer consisting of a silicon single crystal epitaxially grown on a front surface of the silicon single crystal wafer. A polycrystalline silicon layer having a thickness of not less than 0.5 ?m and not more than 1.5 ?m is formed on a back surface of the silicon single crystal wafer.
    Type: Application
    Filed: August 30, 2005
    Publication date: January 15, 2009
    Inventors: Shinsuke Sadamitsu, Masataka Hourai
  • Patent number: 7397110
    Abstract: A high-resistance silicon wafer is manufactured in which a gettering ability, mechanical strength, and economical efficiency are excellent and an oxygen thermal donor is effectively prevented from being generated in a heat treatment for forming a circuit, which is implemented on the side of a device maker. A heat treatment for forming an oxygen precipitate nucleus is performed at 500 to 900° C. for 5 hours or more in a non-oxidizing atmosphere and a heat treatment for growing an oxygen precipitate is performed at 950 to 1050° C. for 10 hours or more on a high-oxygen and carbon-doped high-resistance silicon wafer in which resistivity is 100 ?cm or more, an oxygen concentration is 14×1017 atoms/cm3 (ASTM F-121, 1979) or more and a carbon concentration is 0.5×1016 atoms/cm3 or more. By these heat treatments, a remaining oxygen concentration in the wafer is controlled to be 12×1017 atoms/cm3 (ASTM F-121, 1979) or less.
    Type: Grant
    Filed: April 16, 2003
    Date of Patent: July 8, 2008
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventors: Nobumitsu Takase, Hideshi Nishikawa, Makoto Ito, Koji Sueoka, Shinsuke Sadamitsu
  • Publication number: 20080118424
    Abstract: There is obtained a silicon wafer which has a large diameter, where no slip generated therein in a wide range of a density of oxygen precipitates even though a heat treatment such as SLA or FLA is applied thereto, and which has high strength. First, by inputting as input parameters combinations of a plurality of types of oxygen concentrations and thermal histories set for manufacture of a silicon wafer a Fokker-Planck equation is solved to calculate each of a diagonal length L and a density D of oxygen precipitates in the wafer after a heat treatment step to form the oxygen precipitates (11) and immediately before a heat treatment step of a device manufacturing process is calculated.
    Type: Application
    Filed: June 21, 2005
    Publication date: May 22, 2008
    Inventors: Shinsuke Sadamitsu, Wataru Sugimura, Masanori Akatsuka, Masataka Hourai
  • Patent number: 7316745
    Abstract: A high-resistance silicon wafer is manufactured, in which a gettering ability and economical efficiency is excellent and an oxygen thermal donor is effectively prevented from being generated in a heat treatment for forming a circuit, which is to be implemented on the side of a device manufacturer. In order to implement the above, a high-temperature heat treatment at 1100° C. or higher is performed on a carbon doped high-resistance and high-oxygen silicon wafer in which specific resistivity is 100 ?cm or more and a carbon concentration is 5×1015 to 5×1017 atoms/cm3 so that a remaining oxygen concentration becomes 6.5×1017 atoms/cm3 or more (Old-ASTM). As this high-temperature treatment, an OD treatment for forming a DZ layer on a wafer surface, a high-temperature annealing treatment for eliminating a COP on the surface layer, a high-temperature heat treatment for forming a BOX layer in a SIMOX wafer manufacturing process and the like can be used.
    Type: Grant
    Filed: June 30, 2003
    Date of Patent: January 8, 2008
    Assignee: Sumco Corporation
    Inventors: Shinsuke Sadamitsu, Nobumitsu Takase, Hiroyuki Takao, Koji Sueoka, Masataka Horai
  • Patent number: 7226571
    Abstract: A high resistivity p type silicon wafer with a resistivity of 100 ?cm or more, in the vicinity of the surface being formed denuded zone, wherein when a heat treatment in the device fabrication process is performed, a p/n type conversion layer due to thermal donor generation is located at a depth to be brought into contact with neither any device active region nor depletion layer region formed in contact therewith or at a depth more than 8 ?m from the surface, and a method for fabricating the same. The high resistivity silicon wafer can cause the influence of thermal donors to disappear without reducing the soluble oxygen concentration in the wafer, whereby even if various heat treatments are performed in the device fabrication process, devices such as CMOS that offer superior characteristics can be fabricated. The wafer has wide application as a substrate for a high-frequency integrated circuit device.
    Type: Grant
    Filed: October 15, 2004
    Date of Patent: June 5, 2007
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventors: Nobumitsu Takase, Shinsuke Sadamitsu, Takayuki Kihara, Masataka Hourai
  • Patent number: 7220308
    Abstract: To suppress a fluctuation in resistivity around a target value to thereby stably manufacture high resistivity silicon single crystals having almost the same resistivity values in a manufacturing method wherein a silicon raw material is molten to manufacture a high resistivity silicon single crystal in the range of from 100 to 2000 ? cm with a CZ method. In a case where poly-silicon produced with a Siemens method using trichlorosilane as raw material is used as the silicon raw material, an impurity concentration in the silicon raw material is selected so as to be controlled in the range of from ?5 to 50 ppta method in terms of (a donor concentration—an acceptor concentration) and the selected poly-silicon is used. In a case of a MCZ method, the poly-silicon is selected in the range of from ?25 to 20 ppta and the selected poly-silicon is used. Instead of the raw material, poly-silicon produced with a Siemens method using monosilane as raw material is used.
    Type: Grant
    Filed: April 21, 2004
    Date of Patent: May 22, 2007
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventors: Nobumitsu Takase, Hideshi Nishikawa, Makoto Ito, Koujl Sueoka, Shinsuke Sadamitsu
  • Publication number: 20070066033
    Abstract: By using oxygen-containing silicon wafers obtained by the CZ method and by combining the first heat treatment comprising controlled heat-up operation (ramping) with the second heat treatment comprising high-temperature heat treatment and medium temperature heat treatment in accordance with the process for producing high-resistance silicon wafers according to the present invention, it is possible to obtain high-resistance silicon wafers capable of maintaining their high resistance even after heat treatment in the process of device manufacture while efficiently inhibiting the formation of oxygen donors and preventing changes in resistivity. Further, excellent epitaxial wafers and SOI wafers can be produced using those high-resistance silicon wafers and, therefore, they can be applied in a wide field including high-frequency communication devices and analog/digital hybrid devices, among others.
    Type: Application
    Filed: August 2, 2004
    Publication date: March 22, 2007
    Inventors: Kazunari Kurita, Shinsuke Sadamitsu, Hiroyuki Takao, Masataka Hourai
  • Publication number: 20050253221
    Abstract: A high-resistance silicon wafer is manufactured in which a gettering ability, mechanical strength, and economical efficiency are excellent and an oxygen thermal donor is effectively prevented from being generated in a heat treatment for forming a circuit, which is implemented on the side of a device maker. A heat treatment for forming an oxygen precipitate nucleus is performed at 500 to 900° C. for 5 hours or more in a non-oxidizing atmosphere and a heat treatment for growing an oxygen precipitate is performed at 950 to 1050° C. for 10 hours or more on a high-oxygen and carbon-doped high-resistance silicon wafer in which resistivity is 100 ?cm or more, an oxygen concentration is 14×1017 atoms/cm3 (ASTM F-121, 1979) or more and a carbon concentration is 0.5×1016 atoms/cm3 or more. By these heat treatments, a remaining oxygen concentration in the wafer is controlled to be 12×1017 atoms/cm3 (ASTM F-121, 1979) or less.
    Type: Application
    Filed: April 16, 2003
    Publication date: November 17, 2005
    Applicant: SUMITOMO MITSUBISHI SILICON CORPORATION
    Inventors: Nobumitsu Takase, Hideshi Nishikawa, Makoto Ito, Koji Sueoka, Shinsuke Sadamitsu
  • Publication number: 20050250349
    Abstract: A high-resistance silicon wafer is manufactured, in which a gettering ability and economical efficiency is excellent and an oxygen thermal donor is effectively prevented from being generated in a heat treatment for forming a circuit, which is to be implemented on the side of a device manufacturer. In order to implement the above, a high-temperature heat treatment at 1100° C. or higher is performed on a carbon doped high-resistance and high-oxygen silicon wafer in which specific resistivity is 100 ?cm or more and a carbon concentration is 5×1015 to 5×1017 atoms/cm3 so that a remaining oxygen concentration becomes 6.5×1017 atoms/cm3 or more (Old-ASTM). As this high-temperature treatment, an OD treatment for forming a DZ layer on a wafer surface, a high-temperature annealing treatment for eliminating a COP on the surface layer, a high-temperature heat treatment for forming a BOX layer in a SIMOX wafer manufacturing process and the like can be used.
    Type: Application
    Filed: June 30, 2003
    Publication date: November 10, 2005
    Applicant: SUMITOMO MITSUBISHI SILICON CORPORATION
    Inventors: Shinsuke Sadamitsu, Nobumitsu Takase, Hiroyuki Takao, Koji Sueoka, Masataka Horai
  • Publication number: 20050127477
    Abstract: A high resistivity p type silicon wafer with a resistivity of 100 ?cm or more, in the vicinity of the surface being formed denuded zone, wherein when a heat treatment in the device fabrication process is performed, a p/n type conversion layer due to thermal donor generation is located at a depth to be brought into contact with neither any device active region nor depletion layer region formed in contact therewith or at a depth more than 8 ?m from the surface, and a method for fabricating the same. The high resistivity silicon wafer can cause the influence of thermal donors to disappear without reducing the soluble oxygen concentration in the wafer, whereby even if various heat treatments are performed in the device fabrication process, devices such as CMOS that offer superior characteristics can be fabricated. The wafer has wide application as a substrate for a high-frequency integrated circuit device.
    Type: Application
    Filed: October 15, 2004
    Publication date: June 16, 2005
    Inventors: Nobumitsu Takase, Shinsuke Sadamitsu, Takayuki Kihara, Masataka Hourai
  • Publication number: 20050103256
    Abstract: Disclosed are high resistivity silicon wafers, wherein the interstitial oxygen concentration thereof is 8×1017 atoms/cm3 (ASTM F121-1979) or less, BMD (Bulk Micro Defect) density—oxygen precipitate within wafer—is 5×107 pieces/cm3 or less, and an electric resistivity thereof is 100?·cm or more. And further disclosed are high resistivity silicon wafers having an electric resistivity of 100?·cm or more, which are cut from crystal region where no COP (Crystal Originated Particle) exist, and in which neither COP (Crystal Originated Particle) nor oxygen precipitate exist at the area from wafer surface to the depth of 5 ?m or more owing to high temperature treatment. It is preferable that, in said high resistivity wafers, carbon concentration in wafers is 1×1016 atoms/cm3 or more (ASTM F123-1981), and/or nitrogen concentration is 1×1013 atoms/cm3 or more.
    Type: Application
    Filed: November 12, 2004
    Publication date: May 19, 2005
    Inventors: Shinsuke Sadamitsu, Masataka Hourai
  • Publication number: 20050000410
    Abstract: To suppress a fluctuation in resistivity around a target value to thereby stably manufacture high resistivity silicon single crystals having almost the same resistivity values in a manufacturing method wherein a silicon raw material is molten to manufacture a high resistivity silicon single crystal in the range of from 100 to 2000 ? cm with a CZ method. In a case where poly-silicon produced with a Siemens method using trichlorosilane as raw material is used as the silicon raw material, an impurity concentration in the silicon raw material is selected so as to be controlled in the range of from ?5 to 50 ppta method in terms of (a donor concentration—an acceptor concentration) and the selected poly-silicon is used. In a case of a MCZ method, the poly-silicon is selected in the range of from ?25 to 20 ppta and the selected poly-silicon is used. Instead of the raw material, poly-silicon produced with a Siemens method using monosilane as raw material is used.
    Type: Application
    Filed: April 21, 2004
    Publication date: January 6, 2005
    Inventors: Nobumitsu Takase, Hideshi Nishikawa, Makoto Ito, Kouji Sueoka, Shinsuke Sadamitsu
  • Patent number: 6803242
    Abstract: In a conventional evaluation method of IG effectivity on Cu in semiconductor silicon substrates, it is required to actually conduct the device process, or a great deal of time, manpower and expenses for manufacturing a MOS device for dielectric breakdown estimation and the like are needed, but in the present invention, the problem was solved by experimentally finding in advance the optimum ranges of the diagonal length and density of oxygen precipitates which make the IG effectivity on Cu favorable, and conducting a heat treatment for the addition of IG effectivity based on a simulation by calculations using Fokker-Planck equations so that the diagonal length and density of plate-like precipitates fall within the optimum ranges.
    Type: Grant
    Filed: April 25, 2003
    Date of Patent: October 12, 2004
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventors: Takayuki Kihara, Shinsuke Sadamitsu, Koji Sueoka
  • Patent number: 6641888
    Abstract: There are provided silicon single crystal, silicon wafer, and epitaxial wafer having a sufficient gettering effect suitable for a large-scale integrated device. The silicon single crystal which is suitable for an epitaxial wafer is grown with nitrogen doping at a concentration of 1×1013 atoms/cm3 or more, or with nitrogen doping at a concentration of 1×1012 atoms/cm3 and carbon doping at a concentration of 0.1×1016−5×1016 atoms/cm3 and/or boron doping at a concentration of 1×1017 atoms/cm3 or more. The silicon wafer is produced by slicing from the silicon single crystal, and an epitaxial layer is grown on a surface of the silicon wafer to produce the epitaxial wafer. The present invention provides an epitaxial wafer for a large-scale integrated device having no defects in a device-active region and having an excellent gettering effect without performance of an extrinsic or intrinsic gettering treatment.
    Type: Grant
    Filed: January 25, 2002
    Date of Patent: November 4, 2003
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventors: Eiichi Asayama, Masataka Horai, Shigeru Umeno, Shinsuke Sadamitsu, Yasuo Koike, Kouji Sueoka, Hisashi Katahama
  • Publication number: 20030203519
    Abstract: In a conventional evaluation method of IG effectivity on Cu in semiconductor silicon substrates, it is required to actually conduct the device process, or a great deal of time, manpower and expenses for manufacturing a MOS device for dielectric breakdown estimation and the like are needed, but in the present invention, the problem was solved by experimentally finding in advance the optimum ranges of the diagonal length and density of oxygen precipitates which make the IG effectivity on Cu favorable, and conducting a heat treatment for the addition of IG effectivity based on a simulation by calculations using Fokker-Planck equations so that the diagonal length and density of plate-like precipitates fall within the optimum ranges.
    Type: Application
    Filed: April 25, 2003
    Publication date: October 30, 2003
    Inventors: Takayuki Kihara, Shinsuke Sadamitsu, Koji Sueoka
  • Publication number: 20020142171
    Abstract: There are provided silicon single crystal, silicon wafer, and epitaxial wafer having a sufficient gettering effect suitable for a large-scale integrated device. The silicon single crystal which is suitable for an epitaxial wafer is grown with nitrogen doping at a concentration of 1×1013 atoms/cm3 or more, or with nitrogen doping at a concentration of 1×1012 atoms/cm3 and carbon doping at a concentration of 0.1×1016-5×1016 atoms/cm3 and/or boron doping at a concentration of 1×1017 atoms/cm3 or more. The silicon wafer is produced by slicing from the silicon single crystal, and an epitaxial layer is grown on a surface of the silicon wafer to produce the epitaxial wafer.
    Type: Application
    Filed: January 25, 2002
    Publication date: October 3, 2002
    Applicant: SUMITOMO METAL INDUSTRIES, LTD.
    Inventors: Eiichi Asayama, Masataka Horai, Hiroki Murakami, Takayuki Kubo, Shigeru Umeno, Shinsuke Sadamitsu, Yasuo Koike, Kouji Sueoka, Hisashi Katahama