Patents by Inventor Steve Markgraf
Steve 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).
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Patent number: 7442253Abstract: 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: GrantFiled: May 24, 2007Date of Patent: October 28, 2008Assignee: 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
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Publication number: 20070224783Abstract: 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: ApplicationFiled: May 24, 2007Publication date: September 27, 2007Applicant: MEMC ELECTRONIC MATERIALS, INC.Inventors: Robert Falster, Joseph Holzer, Marco Cornara, Daniela Gambaro, Massimiliano Olmo, Steve Markgraf, Paolo Mutti, Seamus McQuaid, Bayard Johnson
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Patent number: 7229693Abstract: 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: GrantFiled: February 16, 2005Date of Patent: June 12, 2007Assignee: 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
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Publication number: 20050238905Abstract: 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: ApplicationFiled: April 8, 2005Publication date: October 27, 2005Applicant: MEMC Electronic Materials, Inc.Inventors: Robert Falster, Joseph Holzer, Steve Markgraf, Paolo Mutti, Seamus McQuaid, Bayard Johnson
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Publication number: 20050170610Abstract: 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: ApplicationFiled: February 16, 2005Publication date: August 4, 2005Applicant: MEMC Electronic Materials, Inc.Inventors: Robert Falster, Joseph Holzer, Marco Cornara, Daniela Gambaro, Massimiliano Olmo, Steve Markgraf, Paolo Mutti, Seamus McQuaid, Bayard Johnson
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Patent number: 6896728Abstract: 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: GrantFiled: February 25, 2003Date of Patent: May 24, 2005Assignee: 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
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Patent number: 6840997Abstract: 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: GrantFiled: October 24, 2001Date of Patent: January 11, 2005Assignee: MEMC Electronic Materials, Inc.Inventors: Robert A. Falster, Joseph C. Holzer, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
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Publication number: 20040089224Abstract: 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: ApplicationFiled: October 14, 2003Publication date: May 13, 2004Applicant: MEMC Electronic Materials, Inc.Inventors: Robert J. Falster, Joseph C. Holzer, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
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Publication number: 20040025782Abstract: 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: ApplicationFiled: February 25, 2003Publication date: February 12, 2004Applicant: 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
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Patent number: 6632278Abstract: 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: GrantFiled: April 30, 2002Date of Patent: October 14, 2003Assignee: MEMC Electronic Materials, Inc.Inventors: Robert A. Falster, Joseph C. Holzer, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
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Patent number: 6555194Abstract: 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: GrantFiled: November 2, 2000Date of Patent: April 29, 2003Assignee: 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
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Publication number: 20030051657Abstract: 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: ApplicationFiled: July 3, 2002Publication date: March 20, 2003Applicant: MEMC Electronic Materials, Inc.Inventors: Robert J. Falster, Joseph C. Holzer, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
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Publication number: 20020170485Abstract: 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: ApplicationFiled: April 30, 2002Publication date: November 21, 2002Applicant: MEMC Electronic Materials, Inc.Inventors: Robert J. Falster, Joseph C. Holzer, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
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Publication number: 20020078880Abstract: 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: ApplicationFiled: October 24, 2001Publication date: June 27, 2002Applicant: MEMC Electronic Materials, Inc.Inventors: Robert J. Falster, Joseph C. Holzer, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
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Patent number: 6409826Abstract: 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: GrantFiled: March 23, 2001Date of Patent: June 25, 2002Assignee: MEMC Electronic Materials, Inc.Inventors: Robert A. Falster, Joseph C. Holzer, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
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Patent number: 6379642Abstract: 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: GrantFiled: March 16, 1999Date of Patent: April 30, 2002Assignee: MEMC Electronic Materials, Inc.Inventors: Robert A. Falster, Joseph C. Holzer, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
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Publication number: 20010025597Abstract: 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: ApplicationFiled: March 23, 2001Publication date: October 4, 2001Inventors: Robert J. Falster, Joseph C. Holzer, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
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Patent number: 6254672Abstract: 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: GrantFiled: April 9, 1998Date of Patent: July 3, 2001Assignee: MEMC Electronic Materials, Inc.Inventors: Robert A. Falster, Joseph C. Holzer, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
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Patent number: 6190631Abstract: 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: GrantFiled: April 9, 1998Date of Patent: February 20, 2001Assignee: 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
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Patent number: 5919302Abstract: 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: GrantFiled: April 9, 1998Date of Patent: July 6, 1999Assignee: MEMC Electronic Materials, Inc.Inventors: Robert A. Falster, Joseph C. Holzer, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson