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).
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Patent number: 7771530Abstract: 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: GrantFiled: January 17, 2002Date of Patent: August 10, 2010Assignee: Siltronic AGInventors: Janis Virbulis, Wilfried Von Ammon, Erich Tomzig, Yuri Gelfgat, Lenoid Gorbunov
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Patent number: 7708830Abstract: 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: GrantFiled: August 31, 2006Date of Patent: May 4, 2010Assignee: Siltronic AGInventors: Wilfried Von Ammon, Janis Virbulis, Martin Weber, Thomas Wetzel, Herbert Schmidt
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Patent number: 7335256Abstract: 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: GrantFiled: July 17, 2006Date of Patent: February 26, 2008Assignee: Siltronic AGInventors: Martin Weber, Wilfried von Ammon, Herbert Schmidt, Janis Virbulis, Yuri Gelfgat, Leonid Gorbunov
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Publication number: 20060292890Abstract: 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: ApplicationFiled: August 31, 2006Publication date: December 28, 2006Applicant: Siltronic AGInventors: Wilfried Ammon, Janis Virbulis, Martin Weber, Thomas Wetzel, Herbert Schmidt
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Publication number: 20060254498Abstract: 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: ApplicationFiled: July 17, 2006Publication date: November 16, 2006Applicant: Siltronic AGInventors: Martin Weber, Wilfried von Ammon, Herbert Schmidt, Janis Virbulis, Yuri Gelfgat, Leonid Gorbunov
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Patent number: 7025827Abstract: 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: GrantFiled: April 10, 2003Date of Patent: April 11, 2006Assignee: Siltronic AGInventors: Rolf Knobel, Wilfried Von Ammon, Janis Virbulis, Manfred Grundner
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Patent number: 6840998Abstract: 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: GrantFiled: July 23, 2002Date of Patent: January 11, 2005Assignee: Siltronic AGInventors: Ludwig Altmannshofer, Manfred Grundner, Janis Virbulis
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Publication number: 20040192015Abstract: 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: ApplicationFiled: March 25, 2004Publication date: September 30, 2004Applicant: Siltronic AGInventors: Wilfried Von Ammon, Janis Virbulis, Martin Weber, Thomas Wetzel, Herbert Schmidt
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Publication number: 20040118334Abstract: 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: ApplicationFiled: December 10, 2003Publication date: June 24, 2004Applicant: Wacker Siltronic AGInventors: Martin Weber, Wilfried von Ammon, Herbert Schmidt, Janis Virbulis, Yuri Gelfgat, Leonid Gorbunov
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Publication number: 20030192470Abstract: 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: ApplicationFiled: April 10, 2003Publication date: October 16, 2003Applicant: Wacker Siltronic AGInventors: Rolf Knobel, Wilfried Von Ammon, Janis Virbulis, Manfred Grundner
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Publication number: 20030024469Abstract: 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: ApplicationFiled: July 23, 2002Publication date: February 6, 2003Applicant: Wacker Siltronic Gesellschaft Fur Halbleitermaterialien AGInventors: Ludwig Altmannshofer, Manfred Grundner, Janis Virbulis
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Publication number: 20020092461Abstract: 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: ApplicationFiled: January 17, 2002Publication date: July 18, 2002Inventors: Janis Virbulis, Wilfried Von Ammon, Erich Tomzig, Yuri Gelfgat, Leonid Gorbunov
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Patent number: 6238477Abstract: 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: GrantFiled: March 7, 2000Date of Patent: May 29, 2001Assignee: Wacker Siltronic Gesellschaft für Halbleitermaterialien AGInventors: Wilfried von Ammon, Erich Tomzig, Janis Virbulis
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Patent number: 6132507Abstract: 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: GrantFiled: December 4, 1998Date of Patent: October 17, 2000Assignee: Wacker Siltronic Gesellschaft fur Halbleitermaterialien AGInventors: Wilfried von Ammon, Erich Tomzig, Janis Virbulis