Patents by Inventor Janis Virbulis

Janis Virbulis 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: 7771530
    Abstract: A process for producing a silicon single crystal is by pulling the single crystal from a silicon melt which is contained in a crucible with a diameter of at least 450 mm, above which a heat shield is arranged. The single crystal being pulled has a diameter of at least 200 mm. The silicon melt is exposed to the influence of a traveling magnetic field which exerts a substantially vertically oriented force on the melt in the region of the crucible wall. There is also an apparatus which is suitable for carrying out the process.
    Type: Grant
    Filed: January 17, 2002
    Date of Patent: August 10, 2010
    Assignee: Siltronic AG
    Inventors: Janis Virbulis, Wilfried Von Ammon, Erich Tomzig, Yuri Gelfgat, Lenoid Gorbunov
  • Patent number: 7708830
    Abstract: A method for the production of a silicon single crystal by pulling the single crystal, according to the Czochralski method, from a melt which is held in a rotating crucible, the single crystal growing at a growth front, heat being deliberately supplied to the center of the growth front by a heat flux directed at the growth front. The method produces a silicon single crystal with an oxygen content of from 4*1017 cm?3 to 7.2*1017 cm?3 and a radial concentration change for boron or phosphorus of less than 5%, which has no agglomerated self-point defects. Semiconductor wafers are separated from the single crystal. These semiconductor wafers have may have agglomerated vacancy defects (COPs) as the only self-point defect type or may have certain other defect distributions.
    Type: Grant
    Filed: August 31, 2006
    Date of Patent: May 4, 2010
    Assignee: Siltronic AG
    Inventors: Wilfried Von Ammon, Janis Virbulis, Martin Weber, Thomas Wetzel, Herbert Schmidt
  • Patent number: 7335256
    Abstract: A silicon single crystal which, over an ingot length of over 10 percent of the total ingot length, has a uniform defect picture and narrow radial dopant and oxygen variations. The process in accordance with the Czochralski method involves bringing about a temperature distribution in the melt in the region of the solidification interface which deviates from rotational symmetry.
    Type: Grant
    Filed: July 17, 2006
    Date of Patent: February 26, 2008
    Assignee: Siltronic AG
    Inventors: Martin Weber, Wilfried von Ammon, Herbert Schmidt, Janis Virbulis, Yuri Gelfgat, Leonid Gorbunov
  • Publication number: 20060292890
    Abstract: A method for the production of a silicon single crystal by pulling the single crystal, according to the Czochralski method, from a melt which is held in a rotating crucible, the single crystal growing at a growth front, heat being deliberately supplied to the center of the growth front by a heat flux directed at the growth front. The method produces a silicon single crystal with an oxygen content of from 4*1017 cm?3 to 7.2*1017 cm?3 and a radial concentration change for boron or phosphorus of less than 5%, which has no agglomerated self-point defects. Semiconductor wafers are separated from the single crystal. These semiconductor wafers have may have agglomerated vacancy defects (COPs) as the only self-point defect type or may have certain other defect distributions.
    Type: Application
    Filed: August 31, 2006
    Publication date: December 28, 2006
    Applicant: Siltronic AG
    Inventors: Wilfried Ammon, Janis Virbulis, Martin Weber, Thomas Wetzel, Herbert Schmidt
  • Publication number: 20060254498
    Abstract: A silicon single crystal which, over an ingot length of over 10 percent of the total ingot length, has a uniform defect picture and narrow radial dopant and oxygen variations. The process in accordance with the Czochralski method involves bringing about a temperature distribution in the melt in the region of the solidification interface which deviates from rotational symmetry.
    Type: Application
    Filed: July 17, 2006
    Publication date: November 16, 2006
    Applicant: Siltronic AG
    Inventors: Martin Weber, Wilfried von Ammon, Herbert Schmidt, Janis Virbulis, Yuri Gelfgat, Leonid Gorbunov
  • Patent number: 7025827
    Abstract: A doped semiconductor wafer of float zone-pulled semiconductor material contains a dopant added to a molten material and has a radial macroscopic resistance distribution of less than 12% and striations of ?10% to +10%. There is also a process for producing a doped semiconductor wafer by float zone pulling of a single crystal and dividing up the single crystal, in which process, during the float zone pulling, a molten material which is produced using an induction coil is doped with a dopant. It is exposed to at least one rotating magnetic field and is solidified. The single crystal which is formed during the solidification of the molten material is rotated. The single crystal and the magnetic field are rotated with opposite directions of rotation and the magnetic field has a frequency of 400 to 700 Hz.
    Type: Grant
    Filed: April 10, 2003
    Date of Patent: April 11, 2006
    Assignee: Siltronic AG
    Inventors: Rolf Knobel, Wilfried Von Ammon, Janis Virbulis, Manfred Grundner
  • Patent number: 6840998
    Abstract: A silicon single crystal is produced by crucible-free float zone pulling, has a diameter of at least 200 mm over a length of at least 200 mm and is free of dislocations in the region of this length. A silicon wafer is separated from the silicon single crystal by a process for producing the silicon single crystal. The silicon single crystal is produced by crucible-free float zone pulling in a receptacle, in which an atmosphere of inert gas and nitrogen exerts a pressure of 1.5-2.2 bar, the atmosphere being continuously exchanged, with the volume of the receptacle being exchanged at least twice per hour. A flat coil with an external diameter of at least 220 mm is inserted in order to melt a stock ingot. The single crystal is pulled at a rate in a range from 1.4-2.2 mm/min and is periodically rotated through a sequence of rotation angles.
    Type: Grant
    Filed: July 23, 2002
    Date of Patent: January 11, 2005
    Assignee: Siltronic AG
    Inventors: Ludwig Altmannshofer, Manfred Grundner, Janis Virbulis
  • Publication number: 20040192015
    Abstract: A method for the production of a silicon single crystal by pulling the single crystal, according to the Czochralski method, from a melt which is held in a rotating crucible, the single crystal growing at a growth front, heat being deliberately supplied to the center of the growth front by a heat flux directed at the growth front. The method produces a silicon single crystal with an oxygen content of from 4*1017 cm−3 to 7.2*1017 cm−3 and a radial concentration change for boron or phosphorus of less than 5%, which has no agglomerated self-point defects. Semiconductor wafers are separated from the single crystal. These semiconductor wafers have may have agglomerated vacancy defects (COPs) as the only self-point defect type or may have certain other defect distributions.
    Type: Application
    Filed: March 25, 2004
    Publication date: September 30, 2004
    Applicant: Siltronic AG
    Inventors: Wilfried Von Ammon, Janis Virbulis, Martin Weber, Thomas Wetzel, Herbert Schmidt
  • Publication number: 20040118334
    Abstract: A silicon single crystal which, over an ingot length of over 10 percent of the total ingot length, has a uniform defect picture and narrow radial dopant and oxygen variations. The process in accordance with the Czochralski method involves bringing about a temperature distribution in the melt in the region of the solidification interface which deviates from rotational symmetry.
    Type: Application
    Filed: December 10, 2003
    Publication date: June 24, 2004
    Applicant: Wacker Siltronic AG
    Inventors: Martin Weber, Wilfried von Ammon, Herbert Schmidt, Janis Virbulis, Yuri Gelfgat, Leonid Gorbunov
  • Publication number: 20030192470
    Abstract: A doped semiconductor wafer of float zone-pulled semiconductor material contains a dopant added to a molten material and has a radial macroscopic resistance distribution of less than 12% and striations of −10% to +10%. There is also a process for producing a doped semiconductor wafer by float zone pulling of a single crystal and dividing up the single crystal, in which process, during the float zone pulling, a molten material which is produced using an induction coil is doped with a dopant. It is exposed to at least one rotating magnetic field and is solidified. The single crystal which is formed during the solidification of the molten material is rotated. The single crystal and the magnetic field are rotated with opposite directions of rotation and the magnetic field has a frequency of 400 to 700 Hz.
    Type: Application
    Filed: April 10, 2003
    Publication date: October 16, 2003
    Applicant: Wacker Siltronic AG
    Inventors: Rolf Knobel, Wilfried Von Ammon, Janis Virbulis, Manfred Grundner
  • Publication number: 20030024469
    Abstract: A silicon single crystal is produced by crucible-free float zone pulling, has a diameter of at least 200 mm over a length of at least 200 mm and is free of dislocations in the region of this length. A silicon wafer is separated from the silicon single crystal by a process for producing the silicon single crystal. The silicon single crystal is produced by crucible-free float zone pulling in a receptacle, in which an atmosphere of inert gas and nitrogen exerts a pressure of 1.5-2.2 bar, the atmosphere being continuously exchanged, with the volume of the receptacle being exchanged at least twice per hour. A flat coil with an external diameter of at least 220 mm is inserted in order to melt a stock ingot. The single crystal is pulled at a rate in a range from 1.4-2.2 mm/min and is periodically rotated through a sequence of rotation angles.
    Type: Application
    Filed: July 23, 2002
    Publication date: February 6, 2003
    Applicant: Wacker Siltronic Gesellschaft Fur Halbleitermaterialien AG
    Inventors: Ludwig Altmannshofer, Manfred Grundner, Janis Virbulis
  • Publication number: 20020092461
    Abstract: A process for producing a silicon single crystal is by pulling the single crystal from a silicon melt which is contained in a crucible with a diameter of at least 450 mm, above which a heat shield is arranged. The single crystal being pulled has a diameter of at least 200 mm. The silicon melt is exposed to the influence of a traveling magnetic field which exerts a substantially vertically oriented force on the melt in the region of the crucible wall. There is also an apparatus which is suitable for carrying out the process.
    Type: Application
    Filed: January 17, 2002
    Publication date: July 18, 2002
    Inventors: Janis Virbulis, Wilfried Von Ammon, Erich Tomzig, Yuri Gelfgat, Leonid Gorbunov
  • Patent number: 6238477
    Abstract: A process and device for the production of a single crystal of semiconductor material is by pulling the single crystal from a melt, which is contained in a crucible and is heated by a side heater surrounding the crucible. The melt is additionally heated, in an annular region around the single crystal, by an annular heating device which surrounds the single crystal and is positioned above the melt.
    Type: Grant
    Filed: March 7, 2000
    Date of Patent: May 29, 2001
    Assignee: Wacker Siltronic Gesellschaft für Halbleitermaterialien AG
    Inventors: Wilfried von Ammon, Erich Tomzig, Janis Virbulis
  • Patent number: 6132507
    Abstract: A process and device for the production of a single crystal of semiconductor material is by pulling the single crystal from a melt, which is contained in a crucible and is heated by a side heater surrounding the crucible. The melt is additionally heated, in an annular region around the single crystal, by an annular heating device which surrounds the single crystal and is positioned above the melt.
    Type: Grant
    Filed: December 4, 1998
    Date of Patent: October 17, 2000
    Assignee: Wacker Siltronic Gesellschaft fur Halbleitermaterialien AG
    Inventors: Wilfried von Ammon, Erich Tomzig, Janis Virbulis