Patents by Inventor Steve A. Markgraf

Steve A. Markgraf 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: 7442253
    Abstract: The present invention is directed to a process for producing a silicon wafer which, during the heat treatment cycles of essentially any arbitrary electronic device manufacturing process, may form an ideal, non-uniform depth distribution of oxygen precipitates and may additionally contain an axially symmetric region which is substantially free of agglomerated intrinsic point defects. The process either comprises exposing the wafer's front and back surfaces to different atmospheres, or thermally annealing two wafers in a face-to-face arrangement.
    Type: Grant
    Filed: May 24, 2007
    Date of Patent: October 28, 2008
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Robert J. Falster, Joseph C. Holzer, Marco Cornara, Daniela Gambaro, Massimiliano Olmo, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
  • Publication number: 20070224783
    Abstract: The present invention is directed to a process for producing a silicon wafer which, during the heat treatment cycles of essentially any arbitrary electronic device manufacturing process, may form an ideal, non-uniform depth distribution of oxygen precipitates and may additionally contain an axially symmetric region which is substantially free of agglomerated intrinsic point defects. The process either comprises exposing the wafer's front and back surfaces to different atmospheres, or thermally annealing two wafers in a face-to-face arrangement.
    Type: Application
    Filed: May 24, 2007
    Publication date: September 27, 2007
    Applicant: MEMC ELECTRONIC MATERIALS, INC.
    Inventors: Robert Falster, Joseph Holzer, Marco Cornara, Daniela Gambaro, Massimiliano Olmo, Steve Markgraf, Paolo Mutti, Seamus McQuaid, Bayard Johnson
  • Patent number: 7229693
    Abstract: The present invention is directed to a silicon wafer which, during the heat treatment cycles of essentially any arbitrary electronic device manufacturing process, may form an ideal, non-uniform depth distribution of oxygen precipitates and may additionally contain an axially symmetric region which is substantially free of agglomerated intrinsic point defects.
    Type: Grant
    Filed: February 16, 2005
    Date of Patent: June 12, 2007
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Robert J. Falster, Joseph C. Holzer, Marco Cornara, Daniela Gambaro, Massimiliano Olmo, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
  • Publication number: 20050238905
    Abstract: The present invention relates to single crystal silicon, in ingot or wafer form, having an axially symmetric vacancy dominated region and an axially symmetric silicon self-interstitial dominated region. Both the vacancy dominated and the silicon self-interstitial dominated regions are substantially free of agglomerated intrinsic point defects. The vacancy dominated region has a radial width of at least 15 mm and/or includes the central axis and the silicon self-interstitial dominated region is annular in shape and extends radially outward from the vacancy dominated region to the peripheral edge of the ingot or wafer. In ingot form, the axially symmetric regions have an axial length which is at least 20% of the length of the constant diameter portion of the ingot.
    Type: Application
    Filed: April 8, 2005
    Publication date: October 27, 2005
    Applicant: MEMC Electronic Materials, Inc.
    Inventors: Robert Falster, Joseph Holzer, Steve Markgraf, Paolo Mutti, Seamus McQuaid, Bayard Johnson
  • Publication number: 20050170610
    Abstract: The present invention is directed to a silicon wafer which, during the heat treatment cycles of essentially any arbitrary electronic device manufacturing process, may form an ideal, non-uniform depth distribution of oxygen precipitates and may additionally contain an axially symmetric region which is substantially free of agglomerated intrinsic point defects.
    Type: Application
    Filed: February 16, 2005
    Publication date: August 4, 2005
    Applicant: MEMC Electronic Materials, Inc.
    Inventors: Robert Falster, Joseph Holzer, Marco Cornara, Daniela Gambaro, Massimiliano Olmo, Steve Markgraf, Paolo Mutti, Seamus McQuaid, Bayard Johnson
  • Patent number: 6896728
    Abstract: The present invention is directed to a process for producing a silicon wafer which, during the heat treatment cycles of essentially any arbitrary electronic device manufacturing process, may form an ideal, non-uniform depth distribution of oxygen precipitates and may additionally contain an axially symmetric region which is substantially free of agglomerated intrinsic point defects. The process including growing a single crystal silicon ingot from molten silicon, and as part of the growth process, controlling (i) a growth velocity, v, (ii) an average axial temperature gradient, G0, during the growth of a constant diameter portion of the crystal over a temperature range from solidification to a temperature of no less than about 1325° C., and (iii) a cooling rate of the crystal from a solidification temperature to about 1,050° C., in order to cause the formation of an axially symmetrical segment which is substantially free of agglomerated intrinsic point defects.
    Type: Grant
    Filed: February 25, 2003
    Date of Patent: May 24, 2005
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Robert J. Falster, Joseph C. Holzer, Marco Cornara, Daniela Gambaro, Massimiliano Olmo, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
  • Patent number: 6840997
    Abstract: The present invention relates to a process for growing a single crystal silicon. The process including controlling a growth velocity, v, and an average axial temperature gradient, G0, during the growth of the constant diameter portion of the crystal over the temperature range from solidification to a temperature of no less than about 1325° C., to cause the formation of a first axially symmetrical region in which vacancies, upon cooling of the ingot from the solidification temperature, are the predominant intrinsic point defect and which is substantially free of agglomerated intrinsic point defects, wherein the first axially symmetric region has a width of at least about 50% of the radius of the constant diameter portion of the ingot.
    Type: Grant
    Filed: October 24, 2001
    Date of Patent: January 11, 2005
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Robert A. Falster, Joseph C. Holzer, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
  • Publication number: 20040089224
    Abstract: The present invention relates to single crystal silicon, in ingot or wafer form, which contains an axially symmetric region which is free of agglomerated intrinsic point defects, and a process for the preparation thereof.
    Type: Application
    Filed: October 14, 2003
    Publication date: May 13, 2004
    Applicant: MEMC Electronic Materials, Inc.
    Inventors: Robert J. Falster, Joseph C. Holzer, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
  • Publication number: 20040025782
    Abstract: The present invention is directed to a process for producing a silicon wafer which, during the heat treatment cycles of essentially any arbitrary electronic device manufacturing process, may form an ideal, non-uniform depth distribution of oxygen precipitates and may additionally contain an axially symmetric region which is substantially free of agglomerated intrinsic point defects. The process including growing a single crystal silicon ingot from molten silicon, and as part of the growth process, controlling (i) a growth velocity, v, (ii) an average axial temperature gradient, G0, during the growth of a constant diameter portion of the crystal over a temperature range from solidification to a temperature of no less than about 1325° C., and (iii) a cooling rate of the crystal from a solidification temperature to about 1,050° C., in order to cause the formation of an axially symmetrical segment which is substantially free of agglomerated intrinsic point defects.
    Type: Application
    Filed: February 25, 2003
    Publication date: February 12, 2004
    Applicant: MEMC Electronic Materials, Inc.
    Inventors: Robert J. Falster, Joseph C. Holzer, Marco Cornara, Daniela Gambaro, Massimiliano Olmo, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
  • Patent number: 6632278
    Abstract: The present invention relates to an epitaxial wafer comprising single crystal silicon substrate and an epitaxial layer deposited thereon. The substrate comprises an axially symmetric region which is free of agglomerated intrinsic point defects and wherein silicon self-interstitials are the predominant intrinsic point defect in the axially symmetric region. The present invention further relates to a process for producing such an epitaxial wafer.
    Type: Grant
    Filed: April 30, 2002
    Date of Patent: October 14, 2003
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Robert A. Falster, Joseph C. Holzer, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
  • Patent number: 6555194
    Abstract: The present invention is directed to a process for producing a silicon wafer which, during the heat treatment cycles of essentially any arbitrary electronic device manufacturing process, may form an ideal, non-uniform depth distribution of oxygen precipitates and may additionally contain an axially symmetric region which is substantially free of agglomerated intrinsic point defects. The process including growing a single crystal silicon ingot from molten silicon, and as part of the growth process, controlling (i) a growth velocity, v, (ii) an average axial temperature gradient, G0, during the growth of a constant diameter portion of the crystal over a temperature range from solidification to a temperature of no less than about 1325° C., and (iii) a cooling rate of the crystal from a solidification temperature to about 1,050° C., in order to cause the formation of an axially symmetrical segment which is substantially free of agglomerated intrinsic point defects.
    Type: Grant
    Filed: November 2, 2000
    Date of Patent: April 29, 2003
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Robert A. Falster, Joseph C. Holzer, Marco Cornara, Daniela Gambaro, Massimiliano Olmo, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
  • Publication number: 20030051657
    Abstract: The present invention relates to single crystal silicon, in ingot or wafer form, which contains an axially symmetric region in which vacancies are the predominant intrinsic point defect and which is substantially free of agglomerated vacancy intrinsic point defects, wherein the first axially symmetric region has a width which is at least about 50% of the length of the radius of the ingot, and a process for the preparation thereof.
    Type: Application
    Filed: July 3, 2002
    Publication date: March 20, 2003
    Applicant: MEMC Electronic Materials, Inc.
    Inventors: Robert J. Falster, Joseph C. Holzer, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
  • Publication number: 20020170485
    Abstract: The present invention relates to single crystal silicon, in ingot or wafer form, which contains an axially symmetric region which is free of agglomerated intrinsic point defects, and a process for the preparation thereof. The process for growing the single crystal silicon ingot comprises controlling (i) a growth velocity, v, (ii) an average axial temperature gradient, G0, during the growth of a constant diameter portion of the crystal over a temperature range from solidification to a temperature of no less than about 1325° C., and (iii) a cooling rate of the crystal from a solidification temperature to about 1,050° C., in order to cause the formation of an axially symmetrical segment which is substantially free of agglomerated intrinsic point defects.
    Type: Application
    Filed: April 30, 2002
    Publication date: November 21, 2002
    Applicant: MEMC Electronic Materials, Inc.
    Inventors: Robert J. Falster, Joseph C. Holzer, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
  • Publication number: 20020078880
    Abstract: The present invention relates to single crystal silicon, in ingot or wafer form, which contains an axially symmetric region in which vacancies are the predominant intrinsic point defect and which is substantially free of agglomerated vacancy intrinsic point defects, wherein the first axially symmetric region has a width which is at least about 50% of the length of the radius of the ingot, and a process for the preparation thereof.
    Type: Application
    Filed: October 24, 2001
    Publication date: June 27, 2002
    Applicant: MEMC Electronic Materials, Inc.
    Inventors: Robert J. Falster, Joseph C. Holzer, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
  • Patent number: 6409826
    Abstract: The present invention relates a process for the preparation of single crystal silicon, which contains an axially symmetric region which is free of agglomerated intrinsic point defects. The process for growing the single crystal silicon including controlling the ratio v/G0, where v is the growth velocity and G0 is the average axial temperature gradient during the growth of a constant diameter portion of the crystal over a temperature range from solidification to a temperature of no less than about 1325° C., and a cooling rate of the crystal from a solidification temperature to about 1,050° C., in order to cause the formation of an axially symmetrical segment which is substantially free of agglomerated intrinsic point defects. The control of V/G0 accomplished by controlling heat transfer at the melt/solid interface.
    Type: Grant
    Filed: March 23, 2001
    Date of Patent: June 25, 2002
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Robert A. Falster, Joseph C. Holzer, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
  • Patent number: 6379642
    Abstract: The present invention relates to single crystal silicon, in ingot or wafer form, which contains an axially symmetric region in which vacancies are the predominant intrinsic point defect and which is substantially free of agglomerated vacancy intrinsic point defects, wherein the first axially symmetric region has a width which is at least about 50% of the length of the radius of the ingot, and a process for the preparation thereof.
    Type: Grant
    Filed: March 16, 1999
    Date of Patent: April 30, 2002
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Robert A. Falster, Joseph C. Holzer, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
  • Publication number: 20010025597
    Abstract: The present invention relates to single crystal silicon, in ingot or wafer form, which contains an axially symmetric region which is free of agglomerated intrinsic point defects, and a process for the preparation thereof. The process for growing the single crystal silicon ingot comprises controlling (i) a growth velocity, v, (ii) an average axial temperature gradient, G0, during the growth of a constant diameter portion of the crystal over a temperature range from solidification to a temperature of no less than about 1325° C., and (iii) a cooling rate of the crystal from a solidification temperature to about 1,050° C., in order to cause the formation of an axially symmetrical segment which is substantially free of agglomerated intrinsic point defects.
    Type: Application
    Filed: March 23, 2001
    Publication date: October 4, 2001
    Inventors: Robert J. Falster, Joseph C. Holzer, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
  • Patent number: 6254672
    Abstract: The present invention relates to single crystal silicon, in ingot or wafer form, which contains an axially symmetric region which is free of agglomerated intrinsic point defects, and a process for the preparation thereof. The process for growing the single crystal silicon ingot comprises controlling (i) a growth velocity, v, (ii) an average axial temperature gradient, G0, during the growth of a constant diameter portion of the crystal over a temperature range from solidification to a temperature of no less than about 1325° C., and (iii) a cooling rate of the crystal from a solidification temperature to about 1,050° C., in order to cause the formation of an axially symmetrical segment which is substantially free of agglomerated intrinsic point defects.
    Type: Grant
    Filed: April 9, 1998
    Date of Patent: July 3, 2001
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Robert A. Falster, Joseph C. Holzer, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
  • Patent number: 6190631
    Abstract: A single crystal silicon wafer which, during the heat treatment cycles of essentially any electronic device manufacturing process, will form an ideal, non-uniform depth distribution of oxygen precipitates. The wafer is characterized in that is has a non-uniform distribution of crystal lattice vacancies, the concentration of vacancies in the bulk layer being greater than the concentration of vacancies in the surface layer and the vacancies having a concentration profile in which the peak density of the vacancies is at or near a central plane with the concentration generally decreasing from the position of peak density in the direction of a front surface of the wafer. In one embodiment, the wafer is further characterized in that it has a first axially symmetric region in which vacancies are the predominant intrinsic point defect and which is substantially free of agglomerated intrinsic point defects, wherein the first axially symmetric region comprises a central axis or has a width of at least about 15 mm.
    Type: Grant
    Filed: April 9, 1998
    Date of Patent: February 20, 2001
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Robert A. Falster, Joseph C. Holzer, Marco Cornara, Daniela Gambaro, Massimiliano Olmo, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
  • Patent number: 5919302
    Abstract: The present invention relates to single crystal silicon, in ingot or wafer form, which contains an axially symmetric region in which vacancies are the predominant intrinsic point defect and which is substantially free of agglomerated vacancy intrinsic point defects, wherein the first axially symmetric region comprises the central axis or has a width of at least about 15 mm, and a process for the preparation thereof.
    Type: Grant
    Filed: April 9, 1998
    Date of Patent: July 6, 1999
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Robert A. Falster, Joseph C. Holzer, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson