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: 8629509
    Abstract: High power insulated gate bipolar junction transistors are provided that include a wide band gap semiconductor bipolar junction transistor (“BJT”) and a wide band gap semiconductor MOSFET that is configured to provide a current to the base of the BJT. These devices further include a minority carrier diversion semiconductor layer on the base of the BJT and coupled to the emitter of the BJT, the minority carrier diversion semiconductor layer having a conductivity type opposite the conductivity type of the base of the BJT and forming a heterojunction with the base of the BJT.
    Type: Grant
    Filed: September 10, 2009
    Date of Patent: January 14, 2014
    Assignee: Cree, Inc.
    Inventors: Sei-Hyung Ryu, Qingchun Zhang
  • Patent number: 8618582
    Abstract: Elements of an edge termination structure, such as multiple concentric guard rings, are effectively doped regions in a drift layer. To increase the depth of these doped regions, individual recesses may be formed in a surface of the drift layer where the elements of the edge termination structure are to be formed. Once the recesses are formed in the drift layer, these areas about and at the bottom of the recesses are doped to form the respective edge termination elements.
    Type: Grant
    Filed: September 11, 2011
    Date of Patent: December 31, 2013
    Assignee: Cree, Inc.
    Inventors: Jason Patrick Henning, Qingchun Zhang, Sei-Hyung Ryu, Anant Agarwal, John Williams Palmour, Scott Allen
  • Patent number: 8610130
    Abstract: Metal oxide semiconductor (MOS) power devices are provided including a MOS channel including a semiconductor material having high electron mobility on a silicon carbide (SiC) layer. Related methods are also provided herein.
    Type: Grant
    Filed: October 30, 2009
    Date of Patent: December 17, 2013
    Assignee: Cree, Inc.
    Inventors: Sei-Hyung Ryu, Qingchun Zhang
  • Patent number: 8563986
    Abstract: Semiconductor switching devices include a wide band-gap drift layer having a first conductivity type (e.g., n-type), and first and second wide band-gap well regions having a second conductivity type (e.g., p-type) on the wide band-gap drift layer. First and second wide band-gap source/drain regions of the first conductivity type are on the first and second wide band-gap well regions, respectively. A wide band-gap JFET region having the first conductivity type is provided between the first and second well regions. This JFET region includes a first local JFET region that is adjacent a side surface of the first well region and a second local JFET region that is adjacent a side surface of the second well region. The local JFET regions have doping concentrations that exceed a doping concentration of a central portion of the JFET region that is between the first and second local JFET regions of the JFET region.
    Type: Grant
    Filed: November 3, 2009
    Date of Patent: October 22, 2013
    Assignee: Cree, Inc.
    Inventor: Qingchun Zhang
  • Publication number: 20130264581
    Abstract: A bipolar junction transistor (BJT), which includes a collector layer, a base layer on the collector layer, an emitter layer on the base layer, and a recess region embedded in the collector layer, is disclosed. A base-collector plane is between the base layer and the collector layer. The recess region is may be below the base-collector plane. Further, the recess region and the base layer are a first type of semiconductor material. By embedding the recess region in the collector layer, the recess region and the collector layer form a first P-N junction, which may provide a point of avalanche for the BJT. Further, the collector layer and the base layer form a second P-N junction. By separating the point of avalanche from the second P-N junction, the BJT may avalanche robustly, thereby reducing the likelihood of avalanche induced failures, particularly in silicon carbide (SiC) BJTs.
    Type: Application
    Filed: April 4, 2012
    Publication date: October 10, 2013
    Applicant: CREE, INC.
    Inventors: Qingchun Zhang, Anant K. Agarwal, Lin Cheng
  • Patent number: 8552435
    Abstract: Electronic device structures that compensate for non-uniform etching on a semiconductor wafer and methods of fabricating the same are disclosed. In one embodiment, the electronic device includes a number of layers including a semiconductor base layer of a first doping type formed of a desired semiconductor material, a semiconductor buffer layer on the base layer that is also formed of the desired semiconductor material, and one or more contact layers of a second doping type on the buffer layer. The one or more contact layers are etched to form a second contact region of the electronic device. The buffer layer reduces damage to the semiconductor base layer during fabrication of the electronic device. Preferably, a thickness of the semiconductor buffer layer is selected to compensate for over-etching due to non-uniform etching on a semiconductor wafer on which the electronic device is fabricated.
    Type: Grant
    Filed: July 21, 2010
    Date of Patent: October 8, 2013
    Assignee: Cree, Inc.
    Inventors: Qingchun Zhang, Anant Agarwal
  • Patent number: 8541787
    Abstract: High power wide band-gap MOSFET-gated bipolar junction transistors (“MGT”) are provided that include a first wide band-gap bipolar junction transistor (“BJT”) having a first collector, a first emitter and a first base, a wide band-gap MOSFET having a source region that is configured to provide a current to the base of the first wide band-gap BJT and a second wide band-gap BJT having a second collector that is electrically connected to the first collector, a second emitter that is electrically connected to the first emitter, and a second base that is electrically connected to the first base.
    Type: Grant
    Filed: July 15, 2009
    Date of Patent: September 24, 2013
    Assignee: Cree, Inc.
    Inventor: Qingchun Zhang
  • Patent number: 8536582
    Abstract: A silicon carbide-based power device includes a silicon carbide drift layer having a planar surface that forms an off-axis angle with a <0001> direction of less than 8°.
    Type: Grant
    Filed: November 20, 2009
    Date of Patent: September 17, 2013
    Assignee: Cree, Inc.
    Inventors: Qingchun Zhang, Anant Agarwal, Doyle Craig Capell, Albert Burk, Joseph Sumakeris, Michael O'Loughlin
  • Publication number: 20130207123
    Abstract: A power module is disclosed that includes a housing with an interior chamber wherein multiple switch modules are mounted within the interior chamber. The switch modules comprise multiple transistors and diodes that are interconnected to facilitate switching power to a load. In one embodiment, at least one of the switch modules supports a current density of at least 10 amperes per cm2.
    Type: Application
    Filed: August 17, 2012
    Publication date: August 15, 2013
    Applicant: CREE, INC.
    Inventors: Jason Patrick Henning, Qingchun Zhang, Sei-Hyung Ryu, Anant Kumar Agarwal, John Williams Palmour, Scott Allen
  • Patent number: 8497552
    Abstract: A semiconductor device may include a semiconductor buffer layer having a first conductivity type and a semiconductor mesa having the first conductivity type on a surface of the buffer layer. In addition, a current shifting region having a second conductivity type may be provided adjacent a corner between the semiconductor mesa and the semiconductor buffer layer, and the first and second conductivity types may be different conductivity types. Related methods are also discussed.
    Type: Grant
    Filed: July 30, 2009
    Date of Patent: July 30, 2013
    Assignee: Cree, Inc.
    Inventors: Qingchun Zhang, Anant K. Agarwal
  • Patent number: 8460977
    Abstract: A method of forming an electronic device, including forming a preliminary buffer layer on a drift layer, forming a first layer on the preliminary buffer layer, selectively etching the first layer to form a first mesa that exposes a portion of the preliminary buffer layer, and selectively etching the exposed portion of the preliminary buffer layer to form a second mesa that covers a first portion of the drift layer, that exposes a second portion of the drift layer, and that includes a mesa step that protrudes from the first mesa. Dopants are selectively implanted into the drift layer adjacent the second mesa to form a junction termination region in the drift layer. Dopants are selectively implanted through a horizontal surface of the mesa step into a portion of the drift layer beneath the mesa step to form a buried junction extension in the drift layer.
    Type: Grant
    Filed: December 28, 2011
    Date of Patent: June 11, 2013
    Assignee: Cree, Inc.
    Inventors: Qingchun Zhang, Anant K. Agarwal
  • Patent number: 8432012
    Abstract: A semiconductor device includes a semiconductor layer having a first conductivity type and having a surface in which an active region of the semiconductor device is defined, and a plurality of spaced apart doped regions within the active region. The plurality of doped regions have a second conductivity type that is opposite the first conductivity type and define a plurality of exposed portions of the semiconductor layer within the active region. The plurality of doped regions include a plurality of rows extending in a longitudinal direction. Each of the rows includes a plurality of longitudinally extending segments, and the longitudinally extending segments in a first row at least partially overlap the longitudinally extending segments in an adjacent row in a lateral direction that is perpendicular to the longitudinal direction.
    Type: Grant
    Filed: March 18, 2011
    Date of Patent: April 30, 2013
    Assignee: Cree, Inc.
    Inventors: Qingchun Zhang, Jason Henning
  • Patent number: 8415671
    Abstract: Semiconductor switching devices include a first wide band-gap semiconductor layer having a first conductivity type. First and second wide band-gap well regions that have a second conductivity type that is opposite the first conductivity type are provided on the first wide band-gap semiconductor layer. A non-wide band-gap semiconductor layer having the second conductivity type is provided on the first wide band-gap semiconductor layer. First and second wide band-gap source/drain regions that have the first conductivity type are provided on the first wide band-gap well region. A gate insulation layer is provided on the non-wide band-gap semiconductor layer, and a gate electrode is provided on the gate insulation layer.
    Type: Grant
    Filed: April 16, 2010
    Date of Patent: April 9, 2013
    Assignee: Cree, Inc.
    Inventor: Qingchun Zhang
  • Publication number: 20130062619
    Abstract: Elements of an edge termination structure, such as multiple concentric guard rings, are effectively doped regions in a drift layer. To increase the depth of these doped regions, individual recesses may be formed in a surface of the drift layer where the elements of the edge termination structure are to be formed. Once the recesses are formed in the drift layer, these areas about and at the bottom of the recesses are doped to form the respective edge termination elements.
    Type: Application
    Filed: September 11, 2011
    Publication date: March 14, 2013
    Applicant: CREE, INC.
    Inventors: Jason Patrick Henning, Qingchun Zhang, Sei-Hyung Ryu, Anant Agarwal, John Williams Palmour, Scott Allen
  • Publication number: 20130062723
    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: September 11, 2011
    Publication date: March 14, 2013
    Applicant: CREE, INC.
    Inventors: Jason Patrick Henning, Qingchun Zhang, Sei-Hyung Ryu, Anant Agarwal, John Williams Palmour, Scott Allen
  • Publication number: 20130062620
    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: Application
    Filed: September 11, 2011
    Publication date: March 14, 2013
    Applicant: CREE, INC.
    Inventors: Jason Patrick Henning, Qingchun Zhang, Sei-Hyung Ryu, Anant Agarwal, John Williams Palmour, Scott Allen
  • Patent number: 8384181
    Abstract: A power diode having a silicon mesa atop the drift region includes a first contact positioned on the silicon mesa. The silicon mesa is highly doped p-type or n-type, and the anode may be formed on the mesa. The mesa may include two separate silicon layers, one of which is a Schottky barrier height layer. Under a forward bias, the silicon mesa provides carriers to achieve desirable forward current characteristics. The substrate has a significantly reduced thickness. The diode achieves reverse voltage blocking capability by implanting junction barrier Schottky wells within the body of the diode. The diode utilizes a deeper portion of the drift region to support the reverse bias. The method of forming the diode with a silicon mesa includes forming the mesa within a window on the diode or by thermally or mechanically bonding the silicon layer to the drift region.
    Type: Grant
    Filed: February 9, 2007
    Date of Patent: February 26, 2013
    Assignee: Cree, Inc.
    Inventors: Qingchun Zhang, Sei-Hyung Ryu
  • Publication number: 20130032809
    Abstract: An electronic device includes a silicon carbide layer including an n-type drift region therein, a contact forming 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.
    Type: Application
    Filed: September 6, 2012
    Publication date: February 7, 2013
    Inventors: Scott Thomas Allen, Qingchun Zhang
  • Patent number: 8354690
    Abstract: Provided is a semiconductor bistable switching device that includes a thyristor portion including an anode layer, a drift layer, a gate layer and a cathode layer, the gate layer operable to receive a gate trigger current that, when the anode layer is positively biased relative to the cathode layer, causes the thyristor portion to latch into a conducting mode between the anode and the cathode. The device also includes a transistor portion formed on the thyristor portion, the transistor portion including a source, a drain and a transistor gate, the drain coupled to the cathode of the thyristor portion.
    Type: Grant
    Filed: August 31, 2009
    Date of Patent: January 15, 2013
    Assignee: Cree, Inc.
    Inventors: Robert J. Callanan, Sei-Hyung Ryu, Qingchun Zhang
  • Publication number: 20130009221
    Abstract: A semiconductor device may include a semiconductor layer having a first conductivity type, a well region of a second conductivity type in the semiconductor layer wherein the first and second conductivity types are different, and a terminal region of the first conductivity type in the well region. An epitaxial semiconductor layer may be on the surface of the semiconductor layer including the well region and the terminal region with the epitaxial semiconductor layer having the first conductivity type across the well and terminal regions. A gate electrode may be on the epitaxial semiconductor layer so that the epitaxial semiconductor layer is between the gate electrode and portions of the well region surrounding the terminal region at the surface of the semiconductor layer.
    Type: Application
    Filed: September 10, 2012
    Publication date: January 10, 2013
    Inventors: Brett Adam Hull, Qingchun Zhang