Patents by Inventor Yasuhito Narushima

Yasuhito Narushima 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: 8852340
    Abstract: In consideration of influence of segregation, an evaporation area of a volatile dopant and influence of pulling-up speed at the time of manufacturing a monocrystal using a monocrystal pulling-up device, an evaporation speed formula for calculating evaporation speed of the dopant is derived. At predetermined timing during pulling-up, gas flow volume and inner pressure in a chamber are controlled such that a cumulative evaporation amount of the dopant, calculated based on the evaporation speed formula, becomes a predetermined amount. A difference between a resistivity profile of the monocrystal predicted based on the evaporation speed formula and an actual resistivity profile is made small. Since no volatile dopant is subsequently added, increase in workload on an operator, increase of manufacturing time, an increase in amorphous adhering to the inside of the chamber, and an increase in workload at the time of cleaning the inside of the chamber can be prevented.
    Type: Grant
    Filed: October 4, 2013
    Date of Patent: October 7, 2014
    Assignee: Sumco Techxiv Corporation
    Inventors: Yasuhito Narushima, Fukuo Ogawa, Shinichi Kawazoe, Toshimichi Kubota
  • Patent number: 8840721
    Abstract: The present invention provides a method of producing low-resistivity silicon single crystal containing a dopant at a relatively high concentration by adding a large amount of the dopant to silicon melt when the silicon single crystal is pulled up, with suppressing occurrence of dislocation in the crystal. Specifically, the present invention provides a method of manufacturing silicon single crystal by bringing silicon seed crystal into contact with silicon melt and pulling up the silicon seed crystal while rotating the crystal to grow silicon single crystal whose straight body section has a diameter of ? mm below the silicon seed crystal, the method comprising: the dopant-adding step of adding a dopant to the silicon melt during growth of the straight body section of the silicon single crystal, while rotating the silicon single crystal at a rotational speed of ? rpm (where ??24?(?/25)).
    Type: Grant
    Filed: November 11, 2010
    Date of Patent: September 23, 2014
    Assignee: Sumco Techxiv Corporation
    Inventors: Yasuhito Narushima, Fukuo Ogawa, Toshimichi Kubota
  • Patent number: 8747551
    Abstract: After adding phosphorus (P) and germanium (Ge) into a silicon melt or adding phosphorus into a silicon/germanium melt, a silicon monocrystal is grown from the silicon melt by a Czochralski method, where a phosphorus concentration [P]L(atoms/cm3) in the silicon melt, a Ge concentration in the silicon monocrystal, an average temperature gradient Gave (K/mm) and a pull speed V (mm/min) are controlled to satisfy a formula (1) as follows, a phosphorus concentration [P](atoms/cm3) and the Ge concentration [Ge](atoms/cm3) in the silicon monocrystal satisfy a relationship according to a formula (2) as follows while growing the silicon monocrystal, where dSi(?) represents a lattice constant of silicon, rSi(?) represents a covalent radius of silicon, rP(?) represents a covalent radius of phosphorus, and rGe(?) represents a covalent radius of Ge: [ P ] L + ( 0.3151 × [ Ge ] + 3.806 × 10 18 ) / 1.5 < 0.
    Type: Grant
    Filed: September 26, 2013
    Date of Patent: June 10, 2014
    Assignee: Sumco Techxiv Corporation
    Inventors: Shinichi Kawazoe, Yasuhito Narushima, Toshimichi Kubota, Fukuo Ogawa
  • Patent number: 8715416
    Abstract: A doping device includes a first dopant accommodating portion including an opening on an upper portion to accommodate a first dopant that is evaporated near a surface of a semiconductor melt; a second dopant accommodating portion including a dopant holder that holds a second dopant that is liquefied near the surface of the semiconductor melt while including a communicating hole for delivering the liquefied dopant downwardly, and a conduit tube provided on a lower portion of the dopant holder for delivering the liquefied dopant flowed from the communicating hole to the surface of the semiconductor melt; and a guide provided by a cylinder body of which a lower end is opened and an upper end is closed for guiding dopant gas generated by evaporation of the first dopant to the surface of the semiconductor melt.
    Type: Grant
    Filed: May 23, 2008
    Date of Patent: May 6, 2014
    Assignee: Sumco Techxiv Corporation
    Inventors: Yasuhito Narushima, Shinichi Kawazoe, Fukuo Ogawa, Toshimichi Kubota
  • Publication number: 20140033967
    Abstract: In consideration of influence of segregation, an evaporation area of a volatile dopant and influence of pulling-up speed at the time of manufacturing a monocrystal using a monocrystal pulling-up device, an evaporation speed formula for calculating evaporation speed of the dopant is derived. At predetermined timing during pulling-up, gas flow volume and inner pressure in a chamber are controlled such that a cumulative evaporation amount of the dopant, calculated based on the evaporation speed formula, becomes a predetermined amount. A difference between a resistivity profile of the monocrystal predicted based on the evaporation speed formula and an actual resistivity profile is made small. Since no volatile dopant is subsequently added, increase in workload on an operator, increase of manufacturing time, an increase in amorphous adhering to the inside of the chamber, and an increase in workload at the time of cleaning the inside of the chamber can be prevented.
    Type: Application
    Filed: October 4, 2013
    Publication date: February 6, 2014
    Applicant: SUMCO TECHXIV CORPORATION
    Inventors: Yasuhito NARUSHIMA, Fukuo OGAWA, Shinichi KAWAZOE, Toshimichi KUBOTA
  • Publication number: 20140020617
    Abstract: After adding phosphorus (P) and germanium (Ge) into a silicon melt or adding phosphorus into a silicon/germanium melt, a silicon monocrystal is grown from the silicon melt by a Czochralski method, where a phosphorus concentration [P]L(atoms/cm3) in the silicon melt, a Ge concentration in the silicon monocrystal, an average temperature gradient Gave (K/mm) and a pull speed V (mm/min) are controlled to satisfy a formula (1) as follows, a phosphorus concentration [P](atoms/cm3) and the Ge concentration [Ge](atoms/cm3) in the silicon monocrystal satisfy a relationship according to a formula (2) as follows while growing the silicon monocrystal, where dSi(?) represents a lattice constant of silicon, rSi(?) represents a covalent radius of silicon, rP(?) represents a covalent radius of phosphorus, and rGe(?) represents a covalent radius of Ge: [ P ] L + ( 0.3151 × [ Ge ] + 3.806 × 10 18 ) / 1.5 < 0.
    Type: Application
    Filed: September 26, 2013
    Publication date: January 23, 2014
    Applicant: SUMCO TECHXIV CORPORATION
    Inventors: Shinichi KAWAZOE, Yasuhito NARUSHIMA, Toshimichi KUBOTA, Fukuo OGAWA
  • Patent number: 8580032
    Abstract: In consideration of influence of segregation, an evaporation area of a volatile dopant and influence of a pulling-up speed at the time of manufacturing a monocrystal by use of a monocrystal pulling-up device, an evaporation speed formula for calculating an evaporation speed of the dopant is derived. At a predetermined timing during pulling-up, gas flow volume and inner pressure in a chamber are controlled such that a cumulative evaporation amount of the dopant, calculated based on the evaporation speed formula, becomes a predetermined amount. A difference between a resistivity profile of the monocrystal predicted based on the evaporation speed formula and an actual resistivity profile is made small. Since no volatile dopant is subsequently added, increase in workload on an operator, increase of manufacturing time, an increase in amorphous adhering to the inside of the chamber, and an increase in workload at the time of cleaning the inside of the chamber can be prevented.
    Type: Grant
    Filed: May 7, 2008
    Date of Patent: November 12, 2013
    Assignee: Sumco Techxiv Corporation
    Inventors: Yasuhito Narushima, Fukuo Ogawa, Shinichi Kawazoe, Toshimichi Kubota
  • Patent number: 8574363
    Abstract: After adding phosphorus (P) and germanium (Ge) into a silicon melt or adding phosphorus into a silicon/germanium melt, a silicon monocrystal is grown from the silicon melt by a Czochralski method, where a phosphorus concentration [P]L (atoms/cm3) in the silicon melt, a Ge concentration in the silicon monocrystal, an average temperature gradient Gave (K/mm) and a pull speed V (mm/min) are controlled to satisfy a formula (1) as follows, the phosphorus concentration [P] (atoms/cm3) in the silicon monocrystal is 4.84×1019 atoms/cm3 or more and 8.49×1019 atoms/cm3 or less, and the phosphorus concentration [P] (atoms/cm3) and the Ge concentration [Ge] (atoms/cm3) in the silicon monocrystal satisfy a relationship according to a formula (2) as follows while growing the silicon monocrystal. [P]L+(0.3151×[Ge]+3.806×1019)/1.5<0.5×(Gave/V+43)×1019??(1) [Ge]?6.95×[P]+5.90×1020??(2).
    Type: Grant
    Filed: May 23, 2008
    Date of Patent: November 5, 2013
    Assignee: Sumco Techxiv Corporation
    Inventors: Shinichi Kawazoe, Yasuhito Narushima, Toshimichi Kubota, Fukuo Ogawa
  • Patent number: 8535439
    Abstract: To provide a manufacturing method for a silicon single crystal that can reduce introduction of dislocation thereinto even if a required amount of dopant is added to a melt while growing a straight body portion of a silicon ingot. In a manufacturing method for a silicon single crystal according to the present invention that includes a dopant addition step of adding a dopant to a melt while a straight body portion of a silicon single crystal is growing in a growth step of growing the silicon single crystal by dipping a seed crystal into a silicon melt and then pulling the seed crystal therefrom, in the dopant addition step, a remaining mass of the melt is calculated at the beginning thereof, and the dopant is added to the melt at a rate of 0.01 to 0.035 g/min·kg per minute per 1 kg of the calculated remaining mass of the melt.
    Type: Grant
    Filed: January 8, 2010
    Date of Patent: September 17, 2013
    Assignee: Sumco Techxiv Corporation
    Inventors: Yasuhito Narushima, Toshimichi Kubota, Shinichi Kawazoe, Fukuo Ogawa, Tomohiro Fukuda
  • Patent number: 8518180
    Abstract: A silicon single crystal pull-up apparatus is used to pull up a doped silicon single crystal from a melt by means of the Czochralski process and includes a pull-up furnace, a sample chamber which is externally mounted on the pull-up furnace and houses a sublimable dopant, a shielding means for thermally isolating the interior of the pull-up furnace and the interior of the sample chamber, a sample tube which can be raised and lowered between the interior of the sample chamber and the interior of the pull-up furnace, and a raising and lowering means which is provided with guide rails on which the sample tube can slide and a wire mechanism by which the sample tube is raised and lowered along the guide rails.
    Type: Grant
    Filed: July 28, 2009
    Date of Patent: August 27, 2013
    Assignee: Sumco Techxiv Corporation
    Inventors: Yasuhito Narushima, Shinichi Kawazoe, Fukuo Ogawa, Toshimichi Kubota, Tomohiro Fukuda
  • Patent number: 8409347
    Abstract: In a dopant-injecting method for injecting a volatile dopant into a semiconductor melt, a doping device having an accommodating portion for accommodating a solid dopant and a cylindrical portion into which a gas ejected from the accommodating portion is introduced, a lower end surface of the cylindrical portion being opened to guide the gas to the melt, is used. The sublimation rate of the dopant in the accommodating portion is set in a range from 10 g/min to 50 g/min. Since a flow volume of the volatilized dopant gas is controlled by setting the sublimation rate of the dopant gas in the accommodating portion in the range from 10 g/min to 50 g/min, the melt is not blown off when the gas is blown onto the melt.
    Type: Grant
    Filed: July 20, 2007
    Date of Patent: April 2, 2013
    Assignee: Sumco TechXIV Corporation
    Inventors: Shinichi Kawazoe, Yasuhito Narushima, Toshimichi Kubota
  • Patent number: 8283241
    Abstract: A dopant device includes: a dopant holder that holds Ge which is solid at normal temperature and liquefies the Ge near a surface of the semiconductor melt, the dopant holder including a communicating hole for delivering the liquefied Ge downwardly; a cover portion for covering the Ge held by the dopant holder; and a vent provided on the cover portion for communicating with the outside. A dopant injecting method is carried out using such a dopant device, the dopant injecting method including: loading Ge dopant in a solid state into the doping device; liquefying the solid Ge dopant loaded into the doping device while holding the doping device at a predetermined height from a surface of a semiconductor melt; and doping the semiconductor melt with the liquefied Ge that is flowed from the communicating hole.
    Type: Grant
    Filed: May 23, 2008
    Date of Patent: October 9, 2012
    Assignee: Sumco Techxiv Corporation
    Inventors: Yasuhito Narushima, Shinichi Kawazoe, Fukuo Ogawa, Toshimichi Kubota
  • Patent number: 8110042
    Abstract: Using a pulling-up apparatus, an oxygen concentration of the monocrystal at a predetermined position in a pulling-up direction is controlled based on a relationship in which the oxygen concentration of the monocrystal is decreased as a flow rate of the inactive gas at a position directly above a free surface of the dopant-added melt is increased when the monocrystal is manufactured with a gas flow volume in the chamber being in the range of 40 L/min to 400 L/min and an inner pressure in the chamber being in the range of 5332 Pa to 79980 Pa. Based on the relationship, oxygen concentration is elevated to manufacture the monocrystal having a desirable oxygen concentration. Because the oxygen concentration is controlled under a condition corresponding to a condition where the gas flow rate is rather slow, the difference between a desirable oxygen concentration profile of the monocrystal and an actual oxygen concentration profile is reduced.
    Type: Grant
    Filed: May 7, 2008
    Date of Patent: February 7, 2012
    Assignee: Sumco Techxiv Corporation
    Inventors: Yasuhito Narushima, Shinichi Kawazoe, Fukuo Ogawa, Tsuneaki Tomonaga, Yasuyuki Ohta, Toshimichi Kubota, Shinsuke Nishihara
  • Publication number: 20110259260
    Abstract: A silicon single crystal pull-up apparatus is provided with a chamber into which an inert gas is introduced; a crucible that supports a silicon melt within the chamber; a heater that heats the silicon melt in the crucible; a lifting device for lifting and lowering the crucible; a thermal radiation shield disposed above the crucible; a cylindrical purging tube that is provided inside the thermal radiation shield so as to straighten the inert gas; a CCD camera that photographs the mirror image of the thermal radiation shield reflected on the liquid surface of the silicon melt through the purging tube; a liquid surface level calculator that calculates the liquid surface level of the silicon melt from the position of the mirror image photographed by the camera; and a conversion table creator that creates a conversion table representing a relationship between the liquid surface level of the silicon melt and the mirror image position obtained.
    Type: Application
    Filed: April 11, 2011
    Publication date: October 27, 2011
    Applicant: SUMCO CORPORATION
    Inventors: Keiichi TAKANASHI, Kengo HAYASHI, Yasuhito NARUSHIMA
  • Patent number: 8043428
    Abstract: In growing a silicon monocrystal from a silicon melt added with an N-type dopant by Czochralski method, the monocrystal is grown such that a relationship represented by a formula (1) as follows is satisfied. In the formula (1): a dopant concentration in the silicon melt is represented by C (atoms/cm3); an average temperature gradient of the grown monocrystal is represented by Gave(K/mm); a pulling-up speed is represented by V (mm/min); and a coefficient corresponding to a kind of the dopant is represented by A. By growing the silicon monocrystal under a condition shown in the left to a critical line G1, occurrence of abnormal growth due to compositional supercooling can be prevented.
    Type: Grant
    Filed: May 23, 2008
    Date of Patent: October 25, 2011
    Assignee: Sumco Techxiv Corporation
    Inventors: Shinichi Kawazoe, Toshimichi Kubota, Yasuhito Narushima, Fukuo Ogawa
  • Publication number: 20110140241
    Abstract: A process for production of a silicon ingot, by which a silicon ingot exhibiting a low resistivity even in the top portion can be produced. The process for the production of a silicon ingot comprises includes withdrawing a silicon seed crystal (13) from a silicon melt (11) to grow a silicon single crystal (12), with the silicon seed crystal (13) and the silicon melt (11) containing dopants of the same kind.
    Type: Application
    Filed: August 11, 2009
    Publication date: June 16, 2011
    Applicants: SUMCO TECHXIV CORPORATION, SUMCO CORPORATION
    Inventors: Shinichi Kawazoe, Toshimichi Kubota, Fukuo Ogawa, Yasuhito Narushima
  • Publication number: 20110132257
    Abstract: A silicon single crystal pull-up apparatus is used to pull up a doped silicon single crystal from a melt by means of the Czochralski process and includes a pull-up furnace, a sample chamber which is externally mounted on the pull-up furnace and houses a sublimable dopant, a shielding means for thermally isolating the interior of the pull-up furnace and the interior of the sample chamber, a sample tube which can be raised and lowered between the interior of the sample chamber and the interior of the pull-up furnace, and a raising and lowering means which is provided with guide rails on which the sample tube can slide and a wire mechanism by which the sample tube is raised and lowered along the guide rails.
    Type: Application
    Filed: July 28, 2009
    Publication date: June 9, 2011
    Applicant: SUMCO TECHXIV CORPORATION
    Inventors: Yasuhito Narushima, Shinichi Kawazoe, Fukuo Ogawa, Toshimichi Kubota, Tomohiro Fukuda
  • Publication number: 20110120367
    Abstract: A silicon single crystal pull-up apparatus includes a pull-up furnace, a sample chamber in which a sublimable dopant is housed, a sample tube which can be raised and lowered between the interior of the sample chamber and the interior of the pull-up furnace, a raising and lowering means for raising and lowering the sample tube, a supply pipe which is installed inside the pull-up furnace and supplies the sublimable dopant to a melt, and a connection means for connecting the sample tube and the supply pipe. The connection means is constructed from a ball joint structure comprising a convex member which projects from one end of the sample tube and a concave member which is provided at one end of the supply pipe and is formed to be engageable with the convex member. The contact surfaces of the convex member and the concave member are formed to be curved surfaces.
    Type: Application
    Filed: July 28, 2009
    Publication date: May 26, 2011
    Applicant: SUMCO TECHXIV CORPORATION
    Inventors: Yasuhito Narushima, Shinichi Kawazoe, Fukuo Ogawa, Toshimichi Kubota, Tomohiro Fukuda
  • Publication number: 20110114011
    Abstract: The present invention provides a method of producing low-resistivity silicon single crystal containing a dopant at a relatively high concentration by adding a large amount of the dopant to silicon melt when the silicon single crystal is pulled up, with suppressing occurrence of dislocation in the crystal. Specifically, the present invention provides a method of manufacturing silicon single crystal by bringing silicon seed crystal into contact with silicon melt and pulling up the silicon seed crystal while rotating the crystal to grow silicon single crystal whose straight body section has a diameter of ? mm below the silicon seed crystal, the method comprising: the dopant-adding step of adding a dopant to the silicon melt during growth of the straight body section of the silicon single crystal, while rotating the silicon single crystal at a rotational speed of ? rpm (where ??24?(?/25)).
    Type: Application
    Filed: November 11, 2010
    Publication date: May 19, 2011
    Applicant: SUMCO CORPORATION
    Inventors: Yasuhito NARUSHIMA, Fukuo OGAWA, Toshimichi KUBOTA
  • Publication number: 20110056428
    Abstract: The present invention provides a technique which enables production of single crystal silicon having relatively low resistivity by preventing cell growth during crystal growth from occurring, especially in a case where a relatively large amount of dopant is added to a molten silicon raw material. Specifically, the present invention provides a method of producing single crystal silicon by the Czochralski process, comprising producing single crystal silicon having relatively low resistivity by controlling a height of a solid-liquid interface when the single crystal silicon is pulled up.
    Type: Application
    Filed: September 3, 2010
    Publication date: March 10, 2011
    Applicant: SUMCO CORPORATION
    Inventors: Masayuki Uto, Tuneaki Tomonaga, Toshimichi Kubota, Fukuo Ogawa, Yasuhito Narushima