Patents by Inventor Wilfried von Ammon

Wilfried von Ammon 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: 7387676
    Abstract: In a process for producing silicon semiconductor wafers, a silicon single crystal is pulled using the Czochralski method and is processed to form semiconductor wafers, a ratio V/G of pulling rate V and axial temperature gradient G at a growth front during the pulling of the single crystal being controlled in such a manner that agglomerated vacancy defects above a critical size are formed in the single crystal, the agglomerated vacancy defects, in a region of the semiconductor wafer that is of relevance to electronic components, shrinking during production of the components such that the size in this region no longer exceeds the critical size. Silicon semiconductor wafers with agglomerated vacancy defects in the relevant device region preferably contain agglomerated vacancy defects having an inner surface which is at least partially free of an oxide layer and a size of less than 50 nm.
    Type: Grant
    Filed: June 14, 2006
    Date of Patent: June 17, 2008
    Assignee: Siltronic AG
    Inventors: Wilfried von Ammon, Walter Haeckl, Andreas Huber, Ulrich Lambert
  • Publication number: 20080113171
    Abstract: Silicon wafers having a density of BMDs with sizes between 20 to 40 nm at positions ?20 ?m below the wafer surface in the range of 5×1011/cm3, and a density of BMDs with sizes of ?300 nm?1×107/cm3, exhibit reduced slip dislocation and warpage. The wafers are sliced from a crystal grown under specific conditions and then subjected to both low temperature heat-treatment and high temperature anneal.
    Type: Application
    Filed: September 19, 2007
    Publication date: May 15, 2008
    Applicant: SILTRONIC AG
    Inventors: Katsuhiko Nakai, Wilfried von Ammon, Sei Fukushima, Herbert Schmidt, Martin Weber
  • Publication number: 20080096371
    Abstract: The Czochralski method is used for producing p?-doped and epitaxially coated semiconductor wafers from silicon, wherein a silicon single crystal is pulled, and during the pulling is doped with boron, hydrogen and nitrogen, and the single crystal thus obtained is processed to form p?-doped semiconductor wafers which are epitaxially coated.
    Type: Application
    Filed: October 11, 2007
    Publication date: April 24, 2008
    Applicant: SILTRONIC AG
    Inventors: Wilfried von Ammon, Katsuhiko Nakai, Martin Weber, Herbert Schmidt, Atsushi Ikari
  • 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
  • Patent number: 7235863
    Abstract: A process for producing a single-crystal silicon wafer, comprises the following steps: producing a layer on the front surface of the silicon wafer by epitaxial deposition or production of a layer whose electrical resistance differs from the electrical resistance of the remainder of the silicon wafer on the front surface of the silicon wafer, or production of an external getter layer on the back surface of the silicon wafer, and heat treating the silicon wafer at a temperature which is selected to be such that an inequality (1) [ O ? ? i ] < [ O ? ? i ] eq ? ( T ) ? exp ? ? 2 ? ? SiO ? 2 ? ? r ? ? k ? ? T is satisfied, where [Oi] is an oxygen concentration in the silicon wafer, [Oi]eq(T) is a limit solubility of oxygen in silicon at a temperature T, ?SiO2 is the surface energy of silicon dioxide, ? is a volume of a precipitated oxygen atom, r is a mean COP radius and k the Boltzmann constant, with the silicon wafer, during the heat treatment, at least pa
    Type: Grant
    Filed: July 16, 2004
    Date of Patent: June 26, 2007
    Assignee: Siltronic AG
    Inventors: Christoph Seuring, Robert Hölzl, Reinhold Wahlich, Wilfried Von Ammon
  • Publication number: 20060278157
    Abstract: A process for producing a single-crystal silicon wafer, comprises the following steps: producing a layer on the front surface of the silicon water by epitaxial deposition or production of a layer whose electrical resistance differs from the electrical resistance of the remainder of the silicon wafer on the front surface of the silicon wafer, or production of an external getter layer on the back surface of the silicon wafer, and heat treating the silicon wafer at a temperature which is selected to be such that an inequality (1) [ Oi ] < [ Oi ] eq ? ( T ) ? exp ? 2 ? ? SiO ? ? ? 2 ? ? rkT is satisfied where [Oi] is an oxygen concentration in the silicon wafer, [Oi]eq(T) is a limit colubility of oxygen in silicon at a temperature T, ?sio2 is the surface energy of silicon dioxide, ? is a volume of a precipitated oxygen atom, r is a mean COP and k the Boltzmann constant, with the silicon wafer, during the heat treatment, at least part of the time being exposed to an oxygen-containing
    Type: Application
    Filed: June 29, 2006
    Publication date: December 14, 2006
    Applicant: Siltronic AG
    Inventors: Christoph Seuring, Robert Hoelzl, Reinhold Wahlich, Wilfried Von Ammon
  • 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
  • Publication number: 20060213424
    Abstract: A silicon wafer having no epitaxially deposited layer or layer produced by joining to the silicon wafer, with a nitrogen concentration of 1·1013-8·1014 atoms/cm3, an oxygen concentration of 5.2·1017-7.5·1017 atoms/cm3, a central thickness BMD density of 3·108-2·1010 cm?3, a cumulative length of linear slippages ?3 cm and a cumulative area of areal slippage regions ?7 cm2, the front surface having <45 nitrogen-induced defects of >0.13 ?m LSE in the DNN channel, a layer at least 5 ?m thick, in which ?1·104 COPs/cm3 with a size of ?0.09 ?m occur, and a BMD-free layer ?5 ?m thick. Such wafers may be produced by heat treating the silicon wafer, resting on a substrate holder, a specific substrate holder used depending on the wafer doping. For each holder, maximum heating rates are selected to avoid formation of slippages.
    Type: Application
    Filed: March 22, 2006
    Publication date: September 28, 2006
    Inventors: Timo Mueller, Wilfried von Ammon, Erich Daub, Peter Krottenthaler, Klaus Messmann, Friedrich Passek, Reinhold Wahlich, Arnold Kuehhorn, Johannes Studener
  • Publication number: 20060202310
    Abstract: SOI wafers are manufactured to have very thin device layers of high surface quality. The layer is ? 20 nm in thickness, has an HF density of ? 0.1/cm2, and a surface roughness of 0.2 nm RMS.
    Type: Application
    Filed: March 20, 2006
    Publication date: September 14, 2006
    Applicant: Siltronic AG
    Inventors: Brian Murphy, Reinhold Wahlich, Rudiger Schmolke, Wilfried Von Ammon, James Moreland
  • Patent number: 7052948
    Abstract: The invention relates to a film or a layer made of semi-conducting material with low defect density in the thin layer, and a SOI-disk with a thin silicon layer exhibiting low surface roughness, defect density and thickness variations. The invention also relates to a method for producing a film or a layer made of semi-conductive material. Said method comprises the following steps: a) producing structures from a semi-conductive material with periodically repeated recesses which have a given geometrical structure, b) thermally treating the surface structured material until a layer with periodically repeated hollow spaces is formed under a closed layer on the surface of the material, c) separating the closed layer on the surface along the layer of hollow spaces from the remainder of the semi-conductive material.
    Type: Grant
    Filed: June 27, 2002
    Date of Patent: May 30, 2006
    Assignee: Siltronic AG
    Inventors: Brian Murphy, Reinhold Wahlich, Rüdiger Schmolke, Wilfried Von Ammon, James Moreland
  • 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
  • Publication number: 20050103261
    Abstract: A process for epitaxially coating the front surface of a semiconductor wafer in a CVD reactor, the front surface of the semiconductor wafer being exposed to a process gas which contains a source gas and a carrier gas, and the back surface of the semiconductor wafer being exposed to a displacement gas, wherein the displacement gas contains no more than 5% by volume of hydrogen, with the result that diffusion of dopants out of the back surface of the semiconductor wafer, which is intensified by hydrogen, is substantially avoided. With this process, it is possible to produce a semiconductor wafer with a substrate resistivity of ?100 m?cm and a resistivity of the epitaxial layer of >1 ?cm without back-surface coating, the epitaxial layer of which semiconductor wafer has a resistance inhomogeneity of <10%.
    Type: Application
    Filed: December 23, 2004
    Publication date: May 19, 2005
    Inventors: Wilfried Von Ammon, Ruediger Schmolke, Peter Storck, Wolfgang Siebert
  • Patent number: 6887775
    Abstract: A process for epitaxially coating the front surface of a semiconductor wafer in a CVD reactor, the front surface of the semiconductor wafer being exposed to a process gas which contains a source gas and a carrier gas, and the back surface of the semiconductor wafer being exposed to a displacement gas, wherein the displacement gas contains no more than 5% by volume of hydrogen, with the result that diffusion of dopants out of the back surface of the semiconductor wafer, which is intensified by hydrogen, is substantially avoided. With this process, it is possible to produce a semiconductor wafer with a substrate resistivity of ?100 m?cm and a resistivity of the epitaxial layer of >1 ?cm without back-surface coating, the epitaxial layer of which semiconductor wafer has a resistance inhomogeneity of <10%.
    Type: Grant
    Filed: March 13, 2003
    Date of Patent: May 3, 2005
    Assignee: Siltronic AG
    Inventors: Wilfried Von Ammon, Ruediger Schmolke, Peter Storck, Wolfgang Siebert
  • Patent number: 6843848
    Abstract: A semiconductor wafer made from silicon which is doped with hydrogen. The hydrogen concentration is less than 5*1016 atcm?3 and greater than 1*1012 atcm?3. A method for producing a semiconductor wafer from silicon includes separating the semiconductor wafer from a silicon single crystal, with the single silicon crystal being pulled from a melt, in the presence of hydrogen, using the Czochralski method. The hydrogen partial pressure during the pulling of the single silicon crystal is less than 3 mbar.
    Type: Grant
    Filed: March 20, 2001
    Date of Patent: January 18, 2005
    Assignee: Siltronic AG
    Inventors: Wilfried Von Ammon, Rüdiger Schmolke, Erich Daub, Christoph Frey
  • Patent number: 6803331
    Abstract: A process for the heat treatment of a silicon wafer, during which the silicon wafer is at least temporarily exposed to an oxygen-containing atmosphere, the heat treatment taking place at a temperature which is selected in such a way that the inequality [ Oi ] < [ Oi ] eq ⁢ ( T ) ⁢ exp ⁢ ( 2 ⁢ σ SiO 2 ⁢ Ω rkT ) is satisfied, where [Oi] is the oxygen concentration in the silicon wafer [Oi]eq(T) is the limit solubility of oxygen in silicon at a temperature T, &sgr;SiO2 is the surface energy of silicon dioxide &OHgr; is the volum
    Type: Grant
    Filed: February 4, 2003
    Date of Patent: October 12, 2004
    Assignee: Siltronic AG
    Inventors: Robert Hölzl, Christoph Seuring, Reinhold Wahlich, Wilfried Von Ammon
  • 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: 20040144977
    Abstract: A semiconductor wafer is made of a silicon substrate wafer and an epitaxial silicon layer deposited thereon. The substrate wafer has a specific resistance of 0.1 to 50 &OHgr;cm, an oxygen concentration of less than 7.5*1017 atcm−3 and a nitrogen concentration of 1*1013 to 5*1015 atcm−3. The epitaxial layer is 0.2 to 1.0 &mgr;m thick and has a surface on which fewer than 30 LLS (localized light scattering) defects which are greater in size than 0.085 &mgr;m can be detected. A method for producing the semiconductor wafer has a sequence of steps for providing the substrate wafer with the aforementioned features; heating the substrate wafer in a deposition reactor to a deposition temperature of at least 1120° C.; and depositing the epitaxial layer thereon with a thickness of 0.2 to 1.0 &mgr;m, immediately after the deposition temperature has been reached.
    Type: Application
    Filed: January 13, 2004
    Publication date: July 29, 2004
    Applicant: WACKER SILTRONIC GESELLSCHAFT FUR HALBLEITERMATERIALIEN AG
    Inventors: Reinhard Schauer, Markus Blietz, Wilfried von Ammon, Rudiger Schmolke
  • Publication number: 20040142542
    Abstract: The invention relates to a film or a layer made of semiconducting material with low defect density in the thin layer, and a SOI-disk with a thin silicon layer exhibiting low surface roughness, defect density and thickness variations. The invention also relates to a method for producing a film or a layer made of semi-conductive material. Said method comprises the following steps: a) producing structures from a semi-conductive material with periodically repeated recesses which have a given geometrical structure, b) thermally treating the surface structured material until a layer with periodically repeated hollow spaces is formed under a closed layer on the surface of the material, c) separating the closed layer on the surface along the layer of hollow spaces from the remainder of the semi-conductive material.
    Type: Application
    Filed: December 18, 2003
    Publication date: July 22, 2004
    Inventors: Brian Murphy, Reinhold Wahlich, Rudiger Schmolke, Wilfried Von Ammon, James Moreland
  • 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: 20030219981
    Abstract: A process for epitaxially coating the front surface of a semiconductor wafer in a CVD reactor, the front surface of the semiconductor wafer being exposed to a process gas which contains a source gas and a carrier gas, and the back surface of the semiconductor wafer being exposed to a displacement gas, wherein the displacement gas contains no more than 5% by volume of hydrogen, with the result that diffusion of dopants out of the back surface of the semiconductor wafer, which is intensified by hydrogen, is substantially avoided. With this process, it is possible to produce a semiconductor wafer with a substrate resistivity of ≦100 m&OHgr;cm and a resistivity of the epitaxial layer of >1 &OHgr;cm without back-surface coating, the epitaxial layer of which semiconductor wafer has a resistance inhomogeneity of <10%.
    Type: Application
    Filed: March 13, 2003
    Publication date: November 27, 2003
    Inventors: Wilfried Von Ammon, Rudiger Schmolke, Peter Storck, Wolfgang Siebert