Patents by Inventor Steven Jack Keltner

Steven Jack Keltner 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).

  • Barium doping of molten silicon for use in crystal growing process
    Patent number: 6461427
    Abstract: A process for preparing doped molten silicon for use in a single silicon crystal growing process is disclosed. Polysilicon is doped with barium and melted in a silica crucible containing less than about 0.5% gases insoluble in silicon. During melting and throughout the crystal growing process the barium acts as a devitrification promoter and creates a layer of devitrified silica on the inside crucible surface in contact with the melt resulting in a lower level of contaminants in the melt and grown crystal.
    Type: Grant
    Filed: May 17, 2001
    Date of Patent: October 8, 2002
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Richard Joseph Phillips, Steven Jack Keltner, John Davis Holder
  • Strontium doping of molten silicon for use in crystal growing process
    Patent number: 6350312
    Abstract: A process for preparing strontium doped molten silicon for use in a single silicon crystal growing process is disclosed. Polysilicon is doped strontium and melted in a silica crucible. During melting and throughout the crystal growing process the strontium acts as a devitrification promoter and creates a layer of devitrified silica on the inside crucible surface in contact with the melt resulting in a lower level of contaminants in the melt and grown crystal.
    Type: Grant
    Filed: March 8, 2000
    Date of Patent: February 26, 2002
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Richard Joseph Phillips, Steven Jack Keltner, John Davis Holder
  • Barium doping of molten silicon for use in crystal growing process
    Patent number: 6319313
    Abstract: A process for preparing doped molten silicon for use in a single silicon crystal growing process is disclosed. Polysilicon is doped with barium and melted in a silica crucible containing less than about 0.5% gases insoluble in silicon. During melting and throughout the crystal growing process the barium acts as a devitrification promoter and creates a layer of devitrified silica on the inside crucible surface in contact with the melt resulting in a lower level of contaminants in the melt and grown crystal.
    Type: Grant
    Filed: March 8, 2000
    Date of Patent: November 20, 2001
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Richard Joseph Phillips, Steven Jack Keltner, John Davis Holder
  • Tungsten doped crucible and method for preparing same
    Patent number: 6187089
    Abstract: A process for preparing a quartz crucible having a tungsten doped layer on the inside surface, outside surface, or both the inside surface and the outside surface is disclosed. One or more surfaces of the crucible is exposed to a vaporous tungsten source to anneal the tungsten into the crucible surface and create a tungsten doped layer which behaves similarly to a bubble free layer upon use in a crystal pulling process.
    Type: Grant
    Filed: February 5, 1999
    Date of Patent: February 13, 2001
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Richard Joseph Phillips, Steven Jack Keltner