Patents by Inventor Kaoru Kuramochi
Kaoru Kuramochi 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).
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Patent number: 5683505Abstract: A process for producing single crystals with little OSF generation and excellent dielectric strength of gate oxide films by adjusting the temperature gradient of the silicon single crystal in the direction of pulling. The process is carried out with an apparatus including a crucible which contains the melt of the single crystal material, a heating element which heats the melt, a pulling shaft to grow the single crystal, a protective gas inlet pipe, and a chamber which contains all above mentioned components. In addition, the apparatus is provided with a circular cylinder or a conical shaped heat resistant and heat insulating component below the protective gas inlet pipe.Type: GrantFiled: February 27, 1996Date of Patent: November 4, 1997Assignee: Sumitomo Sitix CorporationInventors: Kaoru Kuramochi, Setsuo Okamoto
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Patent number: 5611857Abstract: A process and apparatus for producing silicon single crystals with excellent dielectric strength of gate oxide films by adjusting the temperature gradient of the pulled-up silicon single crystal without loss of its rate of pulling. The process of producing silicon single crystals by pulling up the single crystal from a melt of material of the single crystal imposes a certain average temperature gradient on the grown single crystal while it is still at high temperature. The apparatus is provided with a heating element outside a crucible and pulling shaft with which a single crystal is pulled up from the melt of the material in the crucible. The ratio of length h of the heating element to the inside diameter .phi. of the crucible is adjusted so as to be between 0.2 and 0.8 whereby the temperature gradient can be maintained below 2.5.degree. C./mm.Type: GrantFiled: June 7, 1995Date of Patent: March 18, 1997Assignee: Sumitomo Sitix CorporationInventors: Yoshihiro Akashi, Kaoru Kuramochi, Setsuo Okamoto, Yasuji Tsujimoto, Makoto Ito
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Patent number: 5575847Abstract: This invention relates to the apparatus and the process for producing single crystals with little OSF generation and excellent dielectric strength of gate oxide films by adjusting the temperature gradient of the silicon single crystal in the direction of pulling. The apparatus is provided with a crucible which contains the melt of the single crystal material, a heating element which heats the melt, a pulling shaft to grow the single crystal, a protective gas inlet pipe, and a chamber which contains all above mentioned components. In addition, the apparatus is provided with a circular cylinder or a cylindrical shaped heat resistant and heat insulating component below the protective gas inlet pipe noted above.Type: GrantFiled: November 8, 1994Date of Patent: November 19, 1996Assignee: Sumitomo Sitix CorporationInventors: Kaoru Kuramochi, Setsuo Okamoto
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Patent number: 5477806Abstract: A solid layer is melted from the upper part thereof by the heat of a heater while the contact area between a molten liquid layer and an inner wall of a crucible is adjusted in a Double Layered CZ method, so that the eluting amount of oxygen from the crucible to the molten liquid layer is controlled. Accordingly, silicon single crystals of the low concentration of oxygen are produced.Type: GrantFiled: March 21, 1994Date of Patent: December 26, 1995Assignee: Sumitomo Sitix CorporationInventors: Yoshihiro Akashi, Setsuo Okamoto, Kaoru Kuramochi, Takayuki Kubo
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Patent number: 5474019Abstract: A process and apparatus for producing silicon single crystals with excellent dielectric strength of gate oxide films by adjusting the temperature gradient of the pulled-up silicon single crystal without loss of its rate of pulling. The process of producing silicon single crystals by pulling up the single crystal from a melt of material of the single crystal imposes a certain average temperature gradient on the grown single crystal while it is still at high temperature. The apparatus is provided with a heating element outside a crucible and pulling shaft with which a single crystal is pulled up from the melt of the material in the crucible. The ratio of length h of the heating element to the inside diameter .phi. of the crucible is adjusted so as to be between 0.2 and 0.8 whereby the temperature gradient can be maintained below 2.5.degree. C./mm.Type: GrantFiled: October 13, 1994Date of Patent: December 12, 1995Assignee: Sumitomo Sitix CorporationInventors: Yoshihiro Akashi, Kaoru Kuramochi, Setsuo Okamoto, Yasuji Tsujimoto, Makoto Ito
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Patent number: 5471949Abstract: A method of producing a silicon single crystal, in which a cylindrical partition is immersed in a molten pure silicon liquid or molten silicon liquid containing a Sb dopant within a crucible and the molten liquid inside the partition is pulled up from the crucible to produce the silicon single crystal, wherein an interval between a lower end of the partition and a crucible bottom is changed to control an oxygen concentration in the pulling-up silicon single crystal. The interval is reduced in the case where the oxygen concentration in the pulling-up silicon single crystal is to be increased while the interval is increased in the case where the oxygen concentration is to be reduced.Type: GrantFiled: October 28, 1994Date of Patent: December 5, 1995Assignee: Sumitomo Sitix CorporationInventors: Kaoru Kuramochi, Makoto Ito, Kiichiro Kitaura
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Patent number: 5392729Abstract: A method of producing a silicon single crystal, in which a cylindrical partition is immersed in a molten pure silicon liquid or molten silicon liquid containing a Sb dopant within a crucible and the molten liquid inside the partition is pulled up from the crucible to produce the silicon single crystal, wherein an interval between a lower end of the partition and a crucible bottom is changed to control an oxygen concentration in the pulling-up silicon single crystal. The interval is reduced in the case where the oxygen concentration in the pulling-up silicon single crystal is to be increased while the interval is increased in the case where the oxygen concentration is to be reduced.Type: GrantFiled: September 26, 1990Date of Patent: February 28, 1995Assignees: Osaka Titanium Co., Ltd., Kyushu Electronic Metal Co., Ltd.Inventors: Kaoru Kuramochi, Makoto Ito, Kiichiro Kitaura
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Patent number: 5260037Abstract: An apparatus and a method for producing a silicon single crystal by Czochralski method, whereby the silicon single crystal is pulled up from a crucible while the crucible is heated by a side heater in the lateral periphery of the crucible and a bottom heater facing the bottom of the crucible. The outputs of the side heater and bottom heater are controlled independently each other so that an oxygen concentration in the pull-up direction of the pulled-up silicon single crystal is rendered uniform. In addition to the output control of the heaters, a magnetic field is applied to a molten liquid in the crucible, so that, a dopant concentration in a radial direction of the pulled-up silicon single crystal is rendered uniform.Type: GrantFiled: June 26, 1992Date of Patent: November 9, 1993Assignees: Osaka Titanium Co., Ltd., Kyushu Electronic Metal Co., Ltd.Inventors: Kiichiro Kitaura, Makoto Ito, Kaoru Kuramochi
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Patent number: 5152867Abstract: An apparatus and a method for producing a silicon single crystal by the Czochralski method, whereby the silicon single crystal is pulled up from a crucible while the crucible is heated by a side heater in the lateral periphery of the crucible and a bottom heater facing the bottom of the crucible. The outputs of the side heater and bottom heater are controlled independently of each other so that an oxygen concentration in the pull-up direction of the pulled-up silicon single crystal is rendered uniform. In addition to the output control of the heaters, a magnetic field is applied to a molten liquid in the crucible, so that, a dopant concentration in a radial direction of the pulled-up silicon single crystal is rendered uniform.Type: GrantFiled: July 19, 1990Date of Patent: October 6, 1992Assignees: Osaka Titanium Co., Ltd., Kyushu Electronic Metal Co., Ltd.Inventors: Kiichiro Kitaura, Makoto Ito, Kaoru Kuramochi