Patents by Inventor Andreas Wohlfart

Andreas Wohlfart 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).

  • Publication number: 20250105757
    Abstract: A three-level power semiconductor module has a housing, with a switching device, with a first, a second and a third DC voltage terminal element which form a group, with an AC voltage terminal element wherein the switching device is formed as a TNPC circuit arrangement, which has a DC branch with an upper first switch, with a lower fourth switch and with a center tap and a T branch with a second switch and with a third switch connected in series with the second switch, wherein the first switch is formed of a plurality of first part switches, a majority of these part switches lie in the direction from the group of DC voltage terminals to the AC voltage terminal on a first straight line wherein the fourth switch is formed of a plurality of fourth part switches, wherein a majority of these part switches lie in the direction from the group of DC voltage terminals to the AC voltage terminal on a second straight line adjacent to the first and the focal points of the second and third switch lie in the direction from
    Type: Application
    Filed: September 25, 2024
    Publication date: March 27, 2025
    Applicant: SEMIKRON DANFOSS ELEKTRONIK GMBH & CO. KG
    Inventors: Peter BECKEDAHL, Andreas WOHLFART, Mathias SPANG
  • Publication number: 20250105758
    Abstract: A three-level power semiconductor module with a housing, with a switching device, with a first, a second and a third DC voltage terminal element, and with an AC voltage terminal element.
    Type: Application
    Filed: September 26, 2024
    Publication date: March 27, 2025
    Applicant: SEMIKRON DANFOSS ELEKTRONIK GMBH & CO. KG
    Inventors: Peter BECKEDAHL, Andreas WOHLFART, Mathias Spang
  • Patent number: 9590046
    Abstract: A method is used for producing an SiC volume monocrystal by sublimation growth. During growth, by sublimation of a powdery SiC source material and by transport of the sublimated gaseous components into the crystal growth region, an SiC growth gas phase is produced there. The SiC volume monocrystal grows by deposition from the SiC growth gas phase on the SiC seed crystal. The SiC seed crystal is bent during a heating phase before such that an SiC crystal structure with a non-homogeneous course of lattice planes is adjusted, the lattice planes at each point have an angle of inclination relative to the direction of the center longitudinal axis and peripheral angles of inclination at a radial edge of the SiC seed crystal differ in terms of amount by at least 0.05° and at most by 0.2° from a central angle of inclination at the site of the center longitudinal axis.
    Type: Grant
    Filed: April 22, 2014
    Date of Patent: March 7, 2017
    Assignee: SiCrystal Aktiengesellschaft
    Inventors: Thomas Straubinger, Michael Vogel, Andreas Wohlfart
  • Patent number: 9376764
    Abstract: The present invention relates to a configuration and in particular a physical vapor transport growth system for simultaneously growing more than one silicon carbide (SiC) bulk crystal. Furthermore, the invention relates to a method for producing such a bulk SiC crystal. A physical vapor transport growth system for simultaneously growing more than one SiC single crystal boule comprises a crucible containing two growth compartments for arranging at least one SiC seed crystal in each of them, and a source material compartment for containing a SiC source material, wherein said source material compartment is arranged symmetrically between said growth compartments and is separated from each of the growth compartments by a gas permeable porous membrane.
    Type: Grant
    Filed: February 15, 2013
    Date of Patent: June 28, 2016
    Assignee: SiCrystal AG
    Inventors: Thomas Ludwig Straubinger, Michael Vogel, Andreas Wohlfart, Erwin Schmitt
  • Patent number: 8865324
    Abstract: A method is used to produce a bulk SiC single crystal. A seed crystal is arranged in a crystal growth region of a growing crucible. An SiC growth gas phase is produced in the crystal growth region. The bulk SiC single crystal having a central longitudinal mid-axis grows by deposition from the SiC growth gas phase, the deposition taking place on a growth interface of the growing bulk SiC single crystal. The SiC growth gas phase is at least partially fed from an SiC source material and contains at least one dopant from the group of nitrogen, aluminum, vanadium and boron. At least in a central main growth region of the growth interface arranged about the longitudinal mid-axis, a lateral temperature gradient of at most 2 K/cm measured perpendicular to the longitudinal mid-axis is adjusted and maintained in this range. The bulk SiC single crystal has a large facet region.
    Type: Grant
    Filed: August 9, 2010
    Date of Patent: October 21, 2014
    Assignee: Sicrystal AG
    Inventors: Thomas Straubinger, Michael Vogel, Andreas Wohlfart
  • Patent number: 8758510
    Abstract: A method is used for producing an SiC volume monocrystal by sublimation growth. During growth, by sublimation of a powdery SiC source material and by transport of the sublimated gaseous components into the crystal growth region, an SiC growth gas phase is produced there. The SiC volume monocrystal grows by deposition from the SiC growth gas phase on the SiC seed crystal. The SiC seed crystal is bent during a heating phase before such that an SiC crystal structure with a non-homogeneous course of lattice planes is adjusted, the lattice planes at each point have an angle of inclination relative to the direction of the center longitudinal axis and peripheral angles of inclination at a radial edge of the SiC seed crystal differ in terms of amount by at least 0.05° and at most by 0.2° from a central angle of inclination at the site of the center longitudinal axis.
    Type: Grant
    Filed: December 28, 2011
    Date of Patent: June 24, 2014
    Assignee: SiCrystal Aktiengesellschaft
    Inventors: Thomas Straubinger, Michael Vogel, Andreas Wohlfart
  • Patent number: 8747982
    Abstract: A method is used for producing an SiC volume monocrystal by sublimation growth. Before the beginning of growth, an SiC seed crystal is arranged in a crystal growth region of a growth crucible and powdery SiC source material is introduced into an SiC storage region of the growth crucible. During the growth, by sublimation of the powdery SiC source material and by transport of the sublimated gaseous components into the crystal growth region, an SiC growth gas phase is produced there. The SiC volume monocrystal having a central center longitudinal axis grows by deposition from the SiC growth gas phase on the SiC seed crystal. The SiC seed crystal is heated substantially without bending during a heating phase before the beginning of growth, so that an SiC crystal structure with a substantially homogeneous course of lattice planes is provided in the SiC seed crystal.
    Type: Grant
    Filed: December 28, 2011
    Date of Patent: June 10, 2014
    Assignee: SiCrystal Aktiengesellschaft
    Inventors: Thomas Straubinger, Michael Vogel, Andreas Wohlfart
  • Publication number: 20130305983
    Abstract: The present invention relates to a configuration and in particular a physical vapor transport growth system for simultaneously growing more than one silicon carbide (SiC) bulk crystal. Furthermore, the invention relates to a method for producing such a bulk SiC crystal. A physical vapor transport growth system for simultaneously growing more than one SiC single crystal boule comprises a crucible containing two growth compartments for arranging at least one SiC seed crystal in each of them, and a source material compartment for containing a SiC source material, wherein said source material compartment is arranged symmetrically between said growth compartments and is separated from each of the growth compartments by a gas permeable porous membrane.
    Type: Application
    Filed: February 15, 2013
    Publication date: November 21, 2013
    Applicant: SICRYSTAL AG
    Inventors: Thomas Ludwig Straubinger, Michael Vogel, Andreas Wohlfart, Erwin Schmitt
  • Publication number: 20100159182
    Abstract: A method is used for producing a bulk SiC crystal having a resistivity of at least 1012 ?cm and a diameter of at least 7.62 cm. An SiC growth gas phase is generated in a crystal growth region. The bulk SiC crystal grows by deposition from the SiC growth gas phase. The SiC growth gas phase is fed from an SiC source material, which is contained in an SiC supply region inside the growing crucible. First dopants which have a flat dopant level at a distance of at most 350 meV from an SiC band edge, and second dopants which have a low-lying dopant level at a distance of at least 500 meV from the SiC band edge, are delivered in gaseous form to the crystal growth region. Bulk SiC crystals are thereby obtained, and large-area SiC substrates obtained therefrom whose resistivity is at least 1012 ?cm everywhere.
    Type: Application
    Filed: December 24, 2009
    Publication date: June 24, 2010
    Applicant: SICRYSTAL AG
    Inventors: Thomas Straubinger, Andreas Wohlfart, Martin Kölbl