Patents by Inventor Asko Vehanen

Asko Vehanen 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: 8803160
    Abstract: A semiconductor device including a drift zone of a first conductivity type serving as a substrate layer having a front side and a back side. A first contact electrode is arranged at the front side of the drift zone. A control region is arranged at the front side and controls an injection of carriers of at least the first conductivity type into the drift zone. A second contact electrode is arranged at the backside of the drift zone. The drift zone is arranged to carry a carrier flow between the first and the second contact electrode. The drift zone includes a silicon carbide wafer with a net carrier concentration less than 1015 cm?3 and a carrier lifetime of at least 50 ns.
    Type: Grant
    Filed: December 29, 2011
    Date of Patent: August 12, 2014
    Assignees: Siced Electronics Development GmbH & Co. KG, Norstel AB
    Inventors: Alexandre Ellison, Björn Magnusson, Asko Vehanen, Dietrich Stephani, Heinz Mitlehner, Peter Friedrichs
  • Publication number: 20120091471
    Abstract: A semiconductor device including a drift zone of a first conductivity type serving as a substrate layer having a front side and a back side. A first contact electrode is arranged at the front side of the drift zone. A control region is arranged at the front side and controls an injection of carriers of at least the first conductivity type into the drift zone. A second contact electrode is arranged at the backside of the drift zone. The drift zone is arranged to carry a carrier flow between the first and the second contact electrode. The drift zone includes a silicon carbide wafer with a net carrier concentration less than 1015 cm?3 and a carrier lifetime of at least 50 ns.
    Type: Application
    Filed: December 29, 2011
    Publication date: April 19, 2012
    Applicants: SICED ELECTRONICS DEVELOPMENT GMBH, NORSTEL AB
    Inventors: Alexandre ELLISON, Björn Magnusson, Asko Vehanen, Dietrich Stephani, Heinz Mitlehner, Peter Friedrichs
  • Patent number: 8097524
    Abstract: A method for manufacturing a silicon carbide single crystal. A silicon carbide single crystal is grown. The crystal has a boron concentration less than 5×1014 cm?3, and a concentration of transition metals impurities less than 5×1014 cm?3. Intrinsic defects in the crystal are minimised. The intrinsic defects include silicon vacancies or carbon vacancies. The crystal is annealed for a desired time at a temperature above 700° C. in an atmosphere containing any of the gases hydrogen or a mixture of hydrogen and an inert gas, such that the density of intrinsic defects and any associated defects is decreased to a concentration low enough to confer to the crystal a desired carrier life time of at least 50 ns at room temperature.
    Type: Grant
    Filed: January 13, 2009
    Date of Patent: January 17, 2012
    Assignees: Norstel AB, Siced Electronics Development GmbH & Co. KG
    Inventors: Alexandre Ellison, Björn Magnusson, Asko Vehanen, Dietrich Stephani, Heinz Mitlehner, Peter Friedrichs
  • Publication number: 20090114924
    Abstract: A method for manufacturing a silicon carbide single crystal. A silicon carbide single crystal is grown. The crystal has a boron concentration less than 5×1014 cm?3, and a concentration of transition metals impurities less than 5×1014 cm?3. Intrinsic defects in the crystal are minimised. The intrinsic defects include silicon vacancies or carbon vacancies. The crystal is annealed for a desired time at a temperature above 700° C. in an atmosphere containing any of the gases hydrogen or a mixture of hydrogen and an inert gas, such that the density of intrinsic defects and any associated defects is decreased to a concentration low enough to confer to the crystal a desired carrier life time of at least 50 ns at room temperature.
    Type: Application
    Filed: January 13, 2009
    Publication date: May 7, 2009
    Applicants: NORSTEL AB, SICED ELECTRONICS DEVELOPMENT GMBH
    Inventors: Alexandre Ellison, Björn Magnusson, Asko Vehanen, Dietrich Stephani, Heinz Mitlehner, Peter Friedrichs
  • Patent number: 7482068
    Abstract: A uniform silicon carbide single crystal with either an n-type or a p-type conductivity. The crystal has a net carrier concentration less than 1015 cm?3 and a carrier lifetime of at least 50 ns at room temperature.
    Type: Grant
    Filed: August 22, 2003
    Date of Patent: January 27, 2009
    Assignees: Norstel AB, SiCED Electronics Development GmbH & Co. KG
    Inventors: Alexandre Ellison, Björn Magnusson, Asko Vehanen, Dietrich Stephani, Heinz Mitlehner, Peter Friedrichs
  • Publication number: 20060137600
    Abstract: A uniform silicon carbide single crystal with either an n-type or a p-type conductivity. The crystal has a net carrier concentration less than 1015 cm?3 and a carrier lifetime of at least 50 ns at room temperature.
    Type: Application
    Filed: August 22, 2003
    Publication date: June 29, 2006
    Inventors: Alexandre Ellison, Bjorn Magnusson, Asko Vehanen, Dietrich Stephani, Heinz Mitlehner, Peter Friedrichs