Patents by Inventor John D. Holder

John D. Holder 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: 5980629
    Abstract: A method of reinforcing a crucible for the containment of molten semiconductor material in a Czochralski process, and of inhibiting formation of dislocations within a single crystal grown by the process. The crucible includes a body of vitreous silica having a bottom wall and a sidewall formation extending up from the bottom wall and defining a cavity for holding the molten semiconductor material. The sidewall formation and bottom wall each have an inner and an outer surface. A first devitrification promoter is deposited on the inner surface of the sidewall formation at a temperature below about 600.degree. C. The deposit is such that, when the crucible is heated above 600.degree. C., a first layer of substantially devitrified silica forms on the inner surface which is capable of promoting substantially uniform dissolution of the inner surface and reducing the release of crystalline silica particulates into the molten semiconductor material as a crystal is pulled from the molten semiconductor material.
    Type: Grant
    Filed: June 14, 1995
    Date of Patent: November 9, 1999
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Richard L. Hansen, Larry E. Drafall, Robert M. McCutchan, John D. Holder, Leon A. Allen, Robert D. Shelley
  • Patent number: 5976247
    Abstract: A crucible in which a semiconductor material is melted and held during a crystal growing process. The crucible includes a body of vitreous silica having a bottom wall and a sidewall formation extending up from the bottom wall and defining a cavity for holding the molten semiconductor material. The sidewall formation has an inner and an outer surface. A first devitrification promoter on the inner surface of the sidewall formation is distributed such that a first layer of substantially devitrified silica is formed on the inner surface of the crucible which is in contact with the molten semiconductor material when the semiconductor material is melted in the crucible during the crystal growing process. A second devitrification promoter on the outer surface of the sidewall formation is distributed such that a second layer of substantially devitrified silica is formed on the outer surface of the crucible when the semiconductor material is melted in the crucible during the crystal growing process.
    Type: Grant
    Filed: June 14, 1995
    Date of Patent: November 2, 1999
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Richard L. Hansen, Larry E. Drafall, Robert M. McCutchan, John D. Holder, Leon A. Allen, Robert D. Shelley
  • Patent number: 5904768
    Abstract: A process and apparatus for regulating the concentration and distribution of oxygen in a single crystal silicon rod pulled from a silicon melt, optionally doped with antimony or arsenic, in accordance with the Czochralski method wherein an atmosphere is maintained over the melt. In batch embodiments of the process, the gas pressure of the atmosphere over the melt is progressively increased to a value in excess of 100 torr as the fraction of silicon melt solidified increases. In continuous embodiments of the process, the gas pressure of the atmosphere over the melt is maintained at or near a constant value in excess of 100 torr. The process and apparatus are further characterized in that a controlled flow of inert gas is used to remove vapors and particulate away from the surface of the rod and melt, resulting in the production of a single crystal silicon rod having zero dislocations.
    Type: Grant
    Filed: October 15, 1996
    Date of Patent: May 18, 1999
    Assignee: MEMC Electronic Materials, Inc.
    Inventor: John D. Holder
  • Patent number: 5795381
    Abstract: Methods for quantifying, in near real-time, the amount of silicon oxide (SiO) volatilized from a pool of molten silicon such as a Czochralski silicon melt and present in the atmosphere over the melt are disclosed. A preferred method includes reacting a gas sample containing SiO withdrawn from the atmosphere over the molten silicon with a reactant to form a detectable reaction product, determining the amount of reaction product formed, and correlating the determined amount of reaction product to the amount of SiO present in the atmosphere. The quantification of SiO is used for monitoring and/or controlling the amount of oxygen in the molten silicon or the oxygen content in single crystal silicon being drawn from the molten silicon. A SiO reaction probe and a system using the probe for monitoring and/or controlling oxygen are also disclosed.
    Type: Grant
    Filed: September 9, 1996
    Date of Patent: August 18, 1998
    Assignee: MEMC Electrical Materials, Inc.
    Inventor: John D. Holder
  • Patent number: 5588993
    Abstract: A process for preparing a molten silicon melt from polycrystalline silicon for use in producing single crystal silicon by the Czochralski method is disclosed. Polycrystalline silicon is initially loaded into a Czochralski crucible, and melted to form a partially melted charge which includes both molten silicon and unmelted polycrystalline silicon. The molten silicon has an upper surface above which the unmelted polycrystalline silicon is partially exposed. Granular-polycrystalline silicon is fed onto the exposed unmelted polycrystalline silicon in a manner sufficient to allow the granular-polycrystalline silicon to dehydrogenate while it is resident on the surface of the unmelted polycrystalline silicon and before it becomes immersed in the molten silicon. The granular-polycrystalline silicon and the unmelted polycrystalline silicon are then fully melted to form a molten silicon melt.
    Type: Grant
    Filed: July 25, 1995
    Date of Patent: December 31, 1996
    Assignee: MEMC Electronic Materials, Inc.
    Inventor: John D. Holder
  • Patent number: 5373807
    Abstract: A method for growing multiple high-purity single crystals from a replenished melt by maintaining the purity of molten source material in the melt held in a crucible in a furnace of the type used for growing high-purity single crystals. The method includes the steps of growing at least one crystal from the source material in the crucible, extracting a portion of a volume of the melt remaining in the crucible, adding high-purity source material to the melt, and growing at least one more single crystal. Extractor apparatus used in the method includes an insulated receptacle having an inlet tube for conducting molten source material into the receptacle. A vacuum attached to the receptacle is used to draw the source material into the receptacle.
    Type: Grant
    Filed: November 8, 1993
    Date of Patent: December 20, 1994
    Assignee: MEMC Electronic Materials, Inc.
    Inventor: John D. Holder
  • Patent number: 5288366
    Abstract: A method for growing multiple high-purity single crystals from a replenished melt by maintaining the purity of molten source material in the melt held in a crucible in a furnace of the type used for growing high-purity single crystals. The method includes the steps of growing at least one crystal from the source material in the crucible, extracting a portion of a volume of the melt remaining in the crucible, adding high-purity source material to the melt, and growing at least one more single crystal. Extractor apparatus used in the method includes an insulated receptacle having an inlet tube for conducting molten source material into the receptacle. A vacuum attached to the receptacle is used to draw the source material into the receptacle.
    Type: Grant
    Filed: April 24, 1992
    Date of Patent: February 22, 1994
    Assignee: MEMC Electronic Materials, Inc.
    Inventor: John D. Holder
  • Patent number: 4231796
    Abstract: An improved method for preparing a cermet comprises preparing a compact having about 85 to 95 percent theoretical density from a mixture of metal and metal oxide powders from a system containing a eutectic composition, and inductively heating the compact in a radiofrequency field to cause the formation of an internal molten zone. The metal oxide particles in the powder mixture are effectively sized relative to the metal particles to permit direct inductive heating of the compact by radiofrequency from room temperature. Surface melting is prevented by external cooling or by effectively sizing the particles in the powder mixture.
    Type: Grant
    Filed: November 28, 1978
    Date of Patent: November 4, 1980
    Assignee: The United States of America as represented by the United States Department of Energy
    Inventors: Grady W. Clark, John D. Holder, Arvid E. Pasto