Patents by Inventor Qingchun Zhang

Qingchun Zhang 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: 8952481
    Abstract: The present disclosure relates to a semiconductor device having a Schottky contact that provides both super surge capability and low reverse-bias leakage current. In one preferred embodiment, the semiconductor device is a Schottky diode and even more preferably a Silicon Carbide (SiC) Schottky diode. However, the semiconductor device may more generally be any type of semiconductor device having a Schottky contact such as, for example, a Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET).
    Type: Grant
    Filed: November 20, 2012
    Date of Patent: February 10, 2015
    Assignee: Cree, Inc.
    Inventors: Qingchun Zhang, Jennifer Duc
  • Patent number: 8928108
    Abstract: An electronic device includes a silicon carbide layer including an n-type drift region therein, a contact forming a junction, such as a Schottky junction, with the drift region, and a p-type junction barrier region on the silicon carbide layer. The p-type junction barrier region includes a p-type polysilicon region forming a P-N heterojunction with the drift region, and the p-type junction barrier region is electrically connected to the contact. Related methods are also disclosed.
    Type: Grant
    Filed: March 8, 2010
    Date of Patent: January 6, 2015
    Assignee: Cree, Inc.
    Inventor: Qingchun Zhang
  • Publication number: 20140363931
    Abstract: An insulated gate bipolar transistor (IGBT) includes a first conductivity type substrate and a second conductivity type drift layer on the substrate. The second conductivity type is opposite the first conductivity type. The IGBT further includes a current suppressing layer on the drift layer. The current suppressing layer has the second conductivity type and has a doping concentration that is larger than a doping concentration of the drift layer. A first conductivity type well region is in the current suppressing layer. The well region has a junction depth that is less than a thickness of the current suppressing layer, and the current suppressing layer extends laterally beneath the well region. A second conductivity type emitter region is in the well region.
    Type: Application
    Filed: August 22, 2014
    Publication date: December 11, 2014
    Inventor: QINGCHUN ZHANG
  • Publication number: 20140319646
    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: Application
    Filed: July 8, 2014
    Publication date: October 30, 2014
    Inventors: Jason Henning, Qingchun Zhang, Sie-Hyung Ryu
  • Patent number: 8866150
    Abstract: A silicon carbide power device is fabricated by forming a p-type silicon carbide epitaxial layer on an n-type silicon carbide substrate, and forming a silicon carbide power device structure on the p-type silicon carbide epitaxial layer. The n-type silicon carbide substrate is at least partially removed, so as to expose the p-type silicon carbide epitaxial layer. An ohmic contact is formed on at least some of the p-type silicon carbide epitaxial layer that is exposed. By at least partially removing the n-type silicon carbide substrate and forming an ohmic contact on the p-type silicon carbide epitaxial layer, the disadvantages of using a p-type substrate may be reduced or eliminated. Related structures are also described.
    Type: Grant
    Filed: May 31, 2007
    Date of Patent: October 21, 2014
    Assignee: Cree, Inc.
    Inventors: Mrinal Kanti Das, Qingchun Zhang, John M. Clayton, Jr., Matthew Donofrio
  • Patent number: 8835987
    Abstract: An insulated gate bipolar transistor (IGBT) includes a first conductivity type substrate and a second conductivity type drift layer on the substrate. The second conductivity type is opposite the first conductivity type. The IGBT further includes a current suppressing layer on the drift layer. The current suppressing layer has the second conductivity type and has a doping concentration that is larger than a doping concentration of the drift layer. A first conductivity type well region is in the current suppressing layer. The well region has a junction depth that is less than a thickness of the current suppressing layer, and the current suppressing layer extends laterally beneath the well region. A second conductivity type emitter region is in the well region.
    Type: Grant
    Filed: February 27, 2007
    Date of Patent: September 16, 2014
    Assignee: Cree, Inc.
    Inventor: Qingchun Zhang
  • Patent number: 8809904
    Abstract: Electronic device structures including semiconductor ledge layers for surface passivation and methods of manufacturing the same are disclosed. In one embodiment, the electronic device includes a number of semiconductor layers of a desired semiconductor material having alternating doping types. The semiconductor layers include a base layer of a first doping type that includes a highly doped well forming a first contact region of the electronic device and one or more contact layers of a second doping type on the base layer that have been etched to form a second contact region of the electronic device. The etching of the one or more contact layers causes substantial crystalline damage, and thus interface charge, on the surface of the base layer. In order to passivate the surface of the base layer, a semiconductor ledge layer of the semiconductor material is epitaxially grown on at least the surface of the base layer.
    Type: Grant
    Filed: July 26, 2010
    Date of Patent: August 19, 2014
    Assignee: Cree, Inc.
    Inventors: Qingchun Zhang, Anant Agarwal
  • 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
  • Publication number: 20140183552
    Abstract: A transistor device having a deep recessed P+ junction is disclosed. The transistor device may comprise a gate and a source on an upper surface of the transistor device, and may include at least one doped well region, wherein the at least one doped well region has a first conductivity type that is different from a conductivity type of a source region within the transistor device and the at least one doped well region is recessed from the upper surface of the transistor device by a depth. The deep recessed P+ junction may be a deep recessed P+ implanted junction within a source contact area. The deep recessed P+ junction may be deeper than a termination structure in the transistor device. The transistor device may be a Silicon Carbide (SIC) MOSFET device.
    Type: Application
    Filed: December 28, 2012
    Publication date: July 3, 2014
    Applicant: Cree, Inc.
    Inventors: Qingchun Zhang, Brett Hull
  • Publication number: 20140183553
    Abstract: A transistor device having reduced electrical field at the gate oxide interface is disclosed. In one embodiment, the transistor device comprises a gate, a source, and a drain, wherein the gate is at least partially in contact with a gate oxide. The transistor device has a P+ region within a JFET region of the transistor device in order to reduce an electrical field on the gate oxide.
    Type: Application
    Filed: December 28, 2012
    Publication date: July 3, 2014
    Applicant: Cree, Inc.
    Inventors: Qingchun Zhang, Brett Hull
  • Publication number: 20140145213
    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: January 31, 2014
    Publication date: May 29, 2014
    Applicant: Cree, Inc.
    Inventors: Jason Patrick Henning, Qingchun Zhang, Sei-Hyung Ryu, Anant Kumar Agarwal, John Williams Palmour, Scott Allen
  • Publication number: 20140145289
    Abstract: The present disclosure relates to a Schottky diode having a drift layer and a Schottky layer. The drift layer is predominantly doped with a doping material of a first conductivity type and has a first surface associated with an active region. The Schottky layer is provided over the active region of the first surface to form a Schottky junction. A plurality of junction barrier elements are formed in the drift layer below the Schottky junction, and a plurality of central implants are also formed in the drift layer below the Schottky junction. In certain embodiments, at least one central implant is provided between each adjacent pair of junction barrier elements.
    Type: Application
    Filed: November 27, 2012
    Publication date: May 29, 2014
    Applicant: Cree, Inc.
    Inventor: Qingchun Zhang
  • Publication number: 20140138705
    Abstract: The present disclosure relates to a semiconductor device having a Schottky contact that provides both super surge capability and low reverse-bias leakage current. In one preferred embodiment, the semiconductor device is a Schottky diode and even more preferably a Silicon Carbide (SiC) Schottky diode. However, the semiconductor device may more generally be any type of semiconductor device having a Schottky contact such as, for example, a Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET).
    Type: Application
    Filed: November 20, 2012
    Publication date: May 22, 2014
    Applicant: CREE, INC.
    Inventors: Qingchun Zhang, Jennifer Duc
  • Patent number: 8710510
    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: Grant
    Filed: June 18, 2007
    Date of Patent: April 29, 2014
    Assignee: Cree, Inc.
    Inventors: Qingchun Zhang, Sei-Hyung Ryu, Charlotte Jonas, Anant K. Agarwal
  • Publication number: 20140097450
    Abstract: An electronic device includes a silicon carbide layer having a first conductivity type and a main junction adjacent a surface of the silicon carbide layer, and a junction termination region at the surface of the silicon carbide layer adjacent the main junction. Charge in the junction termination region decreases with lateral distance from the main junction, and a maximum charge in the junction termination region may be less than about 2×1014 cm?2.
    Type: Application
    Filed: December 11, 2013
    Publication date: April 10, 2014
    Applicants: The University of South Carolina, Cree, Inc.
    Inventors: Qingchun Zhang, Anant K. Agarwal, Tangali S. Sudarshan, Alexander Bolotnikov
  • Patent number: 8680587
    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: September 11, 2011
    Date of Patent: March 25, 2014
    Assignee: Cree, Inc.
    Inventors: Jason Patrick Henning, Qingchun Zhang, Sei-Hyung Ryu, Anant Agarwal, John Williams Palmour, Scott Allen
  • Publication number: 20140077228
    Abstract: An electronic device includes a silicon carbide drift region having a first conductivity type, a Schottky contact on the drift region, and a plurality of junction barrier Schottky (JBS) regions at a surface of the drift region adjacent the Schottky contact. The JBS regions have a second conductivity type opposite the first conductivity type and have a first spacing between adjacent ones of the JBS regions. The device further includes a plurality of surge protection subregions having the second conductivity type. Each of the surge protection subregions has a second spacing between adjacent ones of the surge protection subregions that is less than the first spacing.
    Type: Application
    Filed: November 22, 2013
    Publication date: March 20, 2014
    Applicant: CREE, INC.
    Inventors: Qingchun Zhang, Sei-Hyung Ryu
  • Patent number: 8664665
    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 substrate. A junction barrier array is provided in the drift layer just below the Schottky layer. The elements of the junction barrier array are generally doped regions in the drift layer. To increase the depth of these doped regions, individual recesses may be formed in the surface of the drift layer where the elements of the junction barrier array are to be formed. Once the recesses are formed in the drift layer, areas about and at the bottom of the recesses are doped to form the respective elements of the junction barrier array.
    Type: Grant
    Filed: September 11, 2011
    Date of Patent: March 4, 2014
    Assignee: Cree, Inc.
    Inventors: Jason Patrick Henning, Qingchun Zhang, Sei-Hyung Ryu, Anant Agarwal, John Williams Palmour, Scott Allen
  • Patent number: 8653534
    Abstract: An electronic device includes a silicon carbide drift region having a first conductivity type, a Schottky contact on the drift region, and a plurality of junction barrier Schottky (JBS) regions at a surface of the drift region adjacent the Schottky contact. The JBS regions have a second conductivity type opposite the first conductivity type and have a first spacing between adjacent ones of the JBS regions. The device further includes a plurality of surge protection subregions having the second conductivity type. Each of the surge protection subregions has a second spacing between adjacent ones of the surge protection subregions that is less than the first spacing.
    Type: Grant
    Filed: July 11, 2012
    Date of Patent: February 18, 2014
    Assignee: Cree, Inc.
    Inventors: Qingchun Zhang, Sei-Hyung Ryu
  • Patent number: 8637386
    Abstract: An electronic device includes a silicon carbide layer having a first conductivity type and a main junction adjacent a surface of the silicon carbide layer, and a junction termination region at the surface of the silicon carbide layer adjacent the main junction. Charge in the junction termination region decreases with lateral distance from the main junction, and a maximum charge in the junction termination region may be less than about 2×1014 cm?2.
    Type: Grant
    Filed: March 8, 2010
    Date of Patent: January 28, 2014
    Assignee: Cree, Inc.
    Inventors: Qingchun Zhang, Anant K. Agarwal, Tangali S. Sudarshan, Alexander Bolotnikov