Patents by Inventor Sei-Hyung Ryu

Sei-Hyung Ryu 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: 9337268
    Abstract: A negative bevel edge termination for a Silicon Carbide (SiC) semiconductor device is disclosed. In one embodiment, the negative bevel edge termination includes multiple steps that approximate a smooth negative bevel edge termination at a desired slope. More specifically, in one embodiment, the negative bevel edge termination includes at least five steps, at least ten steps, or at least 15 steps. The desired slope is, in one embodiment, less than or equal to fifteen degrees. In one embodiment, the negative bevel edge termination results in a blocking voltage for the semiconductor device of at least 10 kilovolts (kV) or at least 12 kV. The semiconductor device is preferably, but not necessarily, a thyristor such as a power thyristor, a Bipolar Junction Transistor (BJT), an Insulated Gate Bipolar Transistor (IGBT), a U-channel Metal-Oxide-Semiconductor Field Effect Transistor (UMOSFET), or a PIN diode.
    Type: Grant
    Filed: May 16, 2011
    Date of Patent: May 10, 2016
    Assignee: Cree, Inc.
    Inventors: Qingchun Zhang, Craig Capell, Anant Agarwal, Sei-Hyung Ryu
  • Patent number: 9312256
    Abstract: An electronic device includes a silicon carbide layer having a first conductivity type and having a first surface and a second surface opposite the first surface, and first and second silicon carbide Zener diodes on the silicon carbide layer. Each of the first and second silicon carbide Zener diodes may include a first heavily doped silicon carbide region having a second conductivity type opposite the first conductivity type on the silicon carbide layer, and an ohmic contact on the first heavily doped silicon carbide region.
    Type: Grant
    Filed: April 11, 2013
    Date of Patent: April 12, 2016
    Assignee: Cree, Inc.
    Inventors: Sarah Kay Haney, Sei-Hyung Ryu
  • Patent number: 9312343
    Abstract: A transistor may include a semiconductor drift layer of a first semiconductor material and a semiconductor channel layer on the semiconductor drift layer. The semiconductor channel layer may include a second semiconductor material different than the first semiconductor material. A semiconductor interconnection layer may be electrically coupled between the semiconductor drift layer and the semiconductor channel layer, and the semiconductor interconnection layer may include a third semiconductor material different than the first and second semiconductor materials. In addition, a control electrode may be provided on the semiconductor channel layer.
    Type: Grant
    Filed: October 13, 2009
    Date of Patent: April 12, 2016
    Assignee: Cree, Inc.
    Inventors: Qingchun Zhang, Sei-Hyung Ryu, Anant K. Agarwal, Sarit Dhar
  • Patent number: 9306004
    Abstract: A negative bevel edge termination for a Silicon Carbide (SiC) semiconductor device is disclosed. In one embodiment, the negative bevel edge termination includes multiple steps that approximate a smooth negative bevel edge termination at a desired slope. More specifically, in one embodiment, the negative bevel edge termination includes at least five steps, at least ten steps, or at least 15 steps. The desired slope is, in one embodiment, less than or equal to fifteen degrees. In one embodiment, the negative bevel edge termination results in a blocking voltage for the semiconductor device of at least 10 kilovolts (kV) or at least 12 kV. The semiconductor device is preferably, but not necessarily, a thyristor such as a power thyristor, a Bipolar Junction Transistor (BJT), an Insulated Gate Bipolar Transistor (IGBT), a U-channel Metal-Oxide-Semiconductor Field Effect Transistor (UMOSFET), or a PIN diode.
    Type: Grant
    Filed: May 16, 2011
    Date of Patent: April 5, 2016
    Assignee: Cree, Inc.
    Inventors: Qingchun Zhang, Craig Capell, Anant Agarwal, Sei-Hyung Ryu
  • Patent number: 9269580
    Abstract: Embodiments of a semiconductor device having increased channel mobility and methods of manufacturing thereof are disclosed. In one embodiment, the semiconductor device includes a substrate including a channel region and a gate stack on the substrate over the channel region. The gate stack includes an alkaline earth metal. In one embodiment, the alkaline earth metal is Barium (Ba). In another embodiment, the alkaline earth metal is Strontium (Sr). The alkaline earth metal results in a substantial improvement of the channel mobility of the semiconductor device.
    Type: Grant
    Filed: September 9, 2011
    Date of Patent: February 23, 2016
    Assignee: Cree, Inc.
    Inventors: Sarit Dhar, Lin Cheng, Sei-Hyung Ryu, Anant Agarwal, John Williams Palmour, Jason Gurganus
  • Patent number: 9231122
    Abstract: The present disclosure generally relates to a Schottky diode that has a substrate, a drift layer provided over the substrate, and a Schottky layer provided over an active region of the drift layer. The metal for the Schottky layer and the semiconductor material for the drift layer are selected to provide a low barrier height Schottky junction between the drift layer and the Schottky layer.
    Type: Grant
    Filed: January 31, 2014
    Date of Patent: January 5, 2016
    Assignee: Cree, Inc.
    Inventors: Jason Patrick Henning, Qingchun Zhang, Sei-Hyung Ryu, Anant Kumar Agarwal, John Williams Palmour, Scott Allen
  • Publication number: 20150364584
    Abstract: An IGBT device includes a drift region, a collector contact, an injector region, a pair of junction implants, a gate contact, and an emitter contact. The injector region includes a first surface in contact with the collector contact, a second surface opposite the first surface and in contact with the drift region, and at least one bypass region running between the first surface and the second surface. Notably, the at least one bypass region has a charge carrier that is different from that of the injector region. The pair of junction implants is in the drift region along a surface of the drift region opposite the injector region. The gate contact and the emitter contact are on the surface of the drift region opposite the injector region.
    Type: Application
    Filed: June 12, 2014
    Publication date: December 17, 2015
    Inventors: Sei-Hyung Ryu, Qingchun Zhang
  • Publication number: 20150333191
    Abstract: The present disclosure generally relates to a Schottky diode that has a substrate, a drift layer provided over the substrate, and a Schottky layer provided over an active region of the drift layer. The metal for the Schottky layer and the semiconductor material for the drift layer are selected to provide a low barrier height Schottky junction between the drift layer and the Schottky layer.
    Type: Application
    Filed: July 28, 2015
    Publication date: November 19, 2015
    Inventors: Jason Patrick Henning, Qingchun Zhang, Sei-Hyung Ryu, Anant Kumar Agarwal, John Williams Palmour, Scott Allen
  • Publication number: 20150325655
    Abstract: A metal-insulator-semiconductor field-effect transistor (MISFET) includes a SiC layer with source and drain regions of a first conductivity type spaced apart therein. A first gate insulation layer is on the SiC layer and has a net charge along an interface with the SiC layer that is the same polarity as majority carriers of the source region. A gate contact is on the first gate insulation layer over a channel region of the SiC layer between the source and drain regions. The net charge along the interface between the first gate insulation layer and the SiC layer may deplete majority carriers from an adjacent portion of the channel region between the source and drain regions in the SiC layer, which may increase the threshold voltage of the MISFET and/or increase the electron mobility therein.
    Type: Application
    Filed: August 14, 2014
    Publication date: November 12, 2015
    Inventors: Sarit DHAR, Sei-Hyung Ryu
  • Patent number: 9184237
    Abstract: A vertical power transistor is monolithically packaged on a semiconductor die with gate buffer circuitry. The gate buffer circuitry is adapted to deliver a biasing voltage to a gate contact of the vertical power transistor for switching the device between an ON state and an OFF state. By monolithically packaging the gate buffer circuitry together with the vertical power transistor, parasitic inductance between the gate buffer circuitry and the gate of the vertical power transistor is minimized, thereby decreasing the switching time of the vertical power transistor and reducing switching noise.
    Type: Grant
    Filed: June 25, 2013
    Date of Patent: November 10, 2015
    Assignee: Cree, Inc.
    Inventors: Sei-Hyung Ryu, Craig Capell, Charlotte Jonas, David Grider
  • Publication number: 20150287805
    Abstract: An insulated gate bipolar transistor (IGBT) includes a substrate having a first conductivity type, a drift layer having a second conductivity type opposite the first conductivity type, and a well region in the drift layer and having the first conductivity type. An epitaxial channel adjustment layer is on the drift layer and has the second conductivity type. An emitter region extends from a surface of the epitaxial channel adjustment layer through the epitaxial channel adjustment layer and into the well region. The emitter region has the second conductivity type and at least partially defines a channel region in the well region adjacent to the emitter region. A gate oxide layer is on the channel region, and a gate is on the gate oxide layer. Related methods are also disclosed.
    Type: Application
    Filed: April 24, 2014
    Publication date: October 8, 2015
    Applicant: Cree, Inc.
    Inventors: Qingchun Zhang, Sei-Hyung Ryu, Charlotte Jonas, Anant K. Agarwal
  • Patent number: 9142662
    Abstract: A semiconductor device includes a drift layer having a first conductivity type, a well region in the drift layer having a second conductivity type opposite the first conductivity type, and a source region in the well region, The source region has the first conductivity type and defines a channel region in the well region. The source region includes a lateral source region adjacent the channel region and a plurality of source contact regions extending away from the lateral source region opposite the channel region. A body contact region having the second conductivity type is between at least two of the plurality of source contact regions and is in contact with the well region. A source ohmic contact overlaps at least one of the source contact regions and the body contact region. A minimum dimension of a source contact area of the semiconductor device is defined by an area of overlap between the source ohmic contact and the at least one source contact region.
    Type: Grant
    Filed: May 16, 2011
    Date of Patent: September 22, 2015
    Assignee: Cree, Inc.
    Inventors: Sei-Hyung Ryu, Doyle Craig Capell, Lin Cheng, Sarit Dhar, Charlotte Jonas, Anant Agarwal, John Palmour
  • Patent number: 9136371
    Abstract: A monolithic bidirectional switching device includes a drift layer having a first conductivity type and having an upper surface, and first and second vertical metal-oxide semiconductor (MOS) structures at the upper surface of the drift layer. The drift layer provides a common drain for the first and second vertical MOS structures. The first and second vertical MOS structures are protected by respective first and second edge termination structures at the upper surface of the drift layer. A monolithic bidirectional switching device according to further embodiments includes a vertical MOS structure at the upper surface of the drift layer, and a diode at the upper surface of the drift layer. The drift layer provides a drain for the vertical MOS structure and a cathode for the diode, and the vertical MOS structure and the diode are protected by respective first and second edge termination structures.
    Type: Grant
    Filed: November 17, 2014
    Date of Patent: September 15, 2015
    Assignee: Cree, Inc.
    Inventor: Sei-Hyung Ryu
  • Patent number: 9029945
    Abstract: A semiconductor device includes a drift layer having a first conductivity type, a well region in the drift layer having a second conductivity type opposite the first conductivity type, and a source region in the well region. The source region has the first conductivity type and defines a channel region in the well region. The source region includes a lateral source region adjacent the channel region and a plurality of source contact regions extending away from the lateral source region opposite the channel region. A body contact region having the second conductivity type is between at least two of the plurality of source contact regions and is in contact with the well region. A source ohmic contact overlaps at least one of the source contact regions and the body contact region. A minimum dimension of a source contact area of the semiconductor device is defined by an area of overlap between the source ohmic contact and the at least one source contact region.
    Type: Grant
    Filed: May 6, 2011
    Date of Patent: May 12, 2015
    Assignee: Cree, Inc.
    Inventors: Sei-Hyung Ryu, Doyle Craig Capell, Lin Cheng, Sarit Dhar, Charlotte Jonas, Anant Agarwal, John Palmour
  • Publication number: 20150069417
    Abstract: A monolithic bidirectional switching device includes a drift layer having a first conductivity type and having an upper surface, and first and second vertical metal-oxide semiconductor (MOS) structures at the upper surface of the drift layer. The drift layer provides a common drain for the first and second vertical MOS structures. The first and second vertical MOS structures are protected by respective first and second edge termination structures at the upper surface of the drift layer. A monolithic bidirectional switching device according to further embodiments includes a vertical MOS structure at the upper surface of the drift layer, and a diode at the upper surface of the drift layer. The drift layer provides a drain for the vertical MOS structure and a cathode for the diode, and the vertical MOS structure and the diode are protected by respective first and second edge termination structures.
    Type: Application
    Filed: November 17, 2014
    Publication date: March 12, 2015
    Inventor: Sei-Hyung Ryu
  • Publication number: 20140374773
    Abstract: A vertical power transistor is monolithically packaged on a semiconductor die with gate buffer circuitry. The gate buffer circuitry is adapted to deliver a biasing voltage to a gate contact of the vertical power transistor for switching the device between an ON state and an OFF state. By monolithically packaging the gate buffer circuitry together with the vertical power transistor, parasitic inductance between the gate buffer circuitry and the gate of the vertical power transistor is minimized, thereby decreasing the switching time of the vertical power transistor and reducing switching noise.
    Type: Application
    Filed: June 25, 2013
    Publication date: December 25, 2014
    Inventors: Sei-Hyung Ryu, Craig Capell, Charlotte Jonas, David Grider
  • Patent number: 8901699
    Abstract: Integral structures that block the current conduction of the built-in PiN diode in a junction barrier Schottky (JBS) structure are provided. A Schottky diode may be incorporated in series with the PiN diode, where the Schottky diode is of opposite direction to that of the PiN diode. A series resistance or and insulating layer may be provided between the PiN diode and a Schottky contact. Silicon carbide Schottky diodes and methods of fabricating silicon carbide Schottky diodes that include a silicon carbide junction barrier region disposed within a drift region of the diode are also provided. The junction barrier region includes a first region of silicon carbide having a first doping concentration in the drift region of the diode and a second region of silicon carbide in the drift region and disposed between the first region of silicon carbide and a Schottky contact of the Schottky diode. The second region is in contact with the first region of silicon carbide and the Schottky contact.
    Type: Grant
    Filed: May 11, 2005
    Date of Patent: December 2, 2014
    Assignee: Cree, Inc.
    Inventors: Sei-Hyung Ryu, Anant K. Agarwal
  • Patent number: 8901639
    Abstract: A monolithic bidirectional switching device includes a drift layer having a first conductivity type and having an upper surface, and first and second vertical metal-oxide semiconductor (MOS) structures at the upper surface of the drift layer. The drift layer provides a common drain for the first and second vertical MOS structures. The first and second vertical MOS structures are protected by respective first and second edge termination structures at the upper surface of the drift layer. A monolithic bidirectional switching device according to further embodiments includes a vertical MOS structure at the upper surface of the drift layer, and a diode at the upper surface of the drift layer. The drift layer provides a drain for the vertical MOS structure and a cathode for the diode, and the vertical MOS structure and the diode are protected by respective first and second edge termination structures.
    Type: Grant
    Filed: July 26, 2012
    Date of Patent: December 2, 2014
    Assignee: Cree, Inc.
    Inventor: Sei-Hyung Ryu
  • Patent number: 8841682
    Abstract: A metal-insulator-semiconductor field-effect transistor (MISFET) includes a SiC layer with source and drain regions of a first conductivity type spaced apart therein. A first gate insulation layer is on the SiC layer and has a net charge along an interface with the SiC layer that is the same polarity as majority carriers of the source region. A gate contact is on the first gate insulation layer over a channel region of the SiC layer between the source and drain regions. The net charge along the interface between the first gate insulation layer and the SiC layer may deplete majority carriers from an adjacent portion of the channel region between the source and drain regions in the SiC layer, which may increase the threshold voltage of the MISFET and/or increase the electron mobility therein.
    Type: Grant
    Filed: August 27, 2009
    Date of Patent: September 23, 2014
    Assignee: Cree, Inc.
    Inventors: Sarit Dhar, Sei-Hyung Ryu
  • Patent number: 8803277
    Abstract: An electronic device includes a semiconductor layer, a primary junction in the semiconductor layer, a lightly doped region surrounding the primary junction and a junction termination structure in the lightly doped region adjacent the primary junction. The junction termination structure has an upper boundary, a side boundary, and a corner between the upper boundary and the side boundary, and the lightly doped region extends in a first direction away from the primary junction and normal to a point on the upper boundary by a first distance that is smaller than a second distance by which the lightly doped region extends in a second direction away from the primary junction and normal to a point on the corner. At least one floating guard ring segment may be provided in the semiconductor layer outside the corner of the junction termination structure. Related methods are also disclosed.
    Type: Grant
    Filed: February 10, 2011
    Date of Patent: August 12, 2014
    Assignee: Cree, Inc.
    Inventors: Jason Henning, Qingchun Zhang, Sei-Hyung Ryu