Patents by Inventor Jeffrey B. Casady

Jeffrey B. Casady 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: 7432171
    Abstract: A silicon carbide semi-insulating epitaxy layer is used to create power devices and integrated circuits having significant performance advantages over conventional devices. A silicon carbide semi-insulating layer is formed on a substrate, such as a conducting substrate, and one or more semiconducting devices are formed on the silicon carbide semi-insulating layer. The silicon carbide semi-insulating layer, which includes, for example, 4H or 6H silicon carbide, is formed using a compensating material, the compensating material being selected depending on preferred characteristics for the semi-insulating layer. The compensating material includes, for example, boron, vanadium, chromium, or germanium. Use of a silicon carbide semi-insulating layer provides insulating advantages and improved thermal performance for high power and high frequency semiconductor applications.
    Type: Grant
    Filed: December 19, 2005
    Date of Patent: October 7, 2008
    Assignee: Mississippi State University Research and Technology Corporation (RTC)
    Inventors: Jeffrey B. Casady, Michael Mazzola
  • Patent number: 7242040
    Abstract: A junction field effect transistor is described. The transistor is made from a wide bandgap semiconductor material. The device comprises source, channel, drift and drain semiconductor layers, as well as p-type implanted or Schottky gate regions. The source, channel, drift and drain layers can be epitaxially grown. The ohmic contacts to the source, gate, and drain regions can be formed on the same side of the wafer. The devices can have different threshold voltages depending on the vertical channel width and can be implemented for both depletion and enhanced modes of operation for the same channel doping. The devices can be used for digital, analog, and monolithic microwave integrated circuits. Methods for making the transistors and integrated circuits comprising the devices are also described.
    Type: Grant
    Filed: August 18, 2006
    Date of Patent: July 10, 2007
    Assignee: Semisouth Laboratories, Inc.
    Inventors: Igor Sankin, Jeffrey B. Casady, Joseph N. Merrett
  • Patent number: 7119380
    Abstract: A junction field effect transistor is described. The transistor is made from a wide bandgap semiconductor material. The device comprises source, channel, drift and drain semiconductor layers, as well as p-type implanted or Schottky gate regions. The source, channel, drift and drain layers can be epitaxially grown. The ohmic contacts to the source, gate, and drain regions can be formed on the same side of the wafer. The devices can have different threshold voltages depending on the vertical channel width and can be implemented for both depletion and enhanced modes of operation for the same channel doping. The devices can be used for digital, analog, and monolithic microwave integrated circuits. Methods for making the transistors and integrated circuits comprising the devices are also described.
    Type: Grant
    Filed: December 1, 2004
    Date of Patent: October 10, 2006
    Assignee: SemiSouth Laboratories, Inc.
    Inventors: Igor Sankin, Jeffrey B. Casady, Joseph N. Merrett
  • Patent number: 7009209
    Abstract: A silicon carbide semi-insulating epitaxy layer is used to create power devices and integrated circuits having significant performance advantages over conventional devices. A silicon carbide semi-insulating layer is formed on a substrate, such as a conducting substrate, and one or more semiconducting devices are formed on the silicon carbide semi-insulating layer. The silicon carbide semi-insulating layer, which includes, for example, 4H or 6H silicon carbide, is formed using a compensating material, the compensating material being selected depending on preferred characteristics for the semi-insulating layer. The compensating material includes, for example, boron, vanadium, chromium, or germanium. Use of a silicon carbide semi-insulating layer provides insulating advantages and improved thermal performance for high power and high frequency semiconductor applications.
    Type: Grant
    Filed: January 3, 2002
    Date of Patent: March 7, 2006
    Assignee: Mississippi State University Research and Technology Corporation (RTC)
    Inventors: Jeffrey B. Casady, Michael Mazzola
  • Patent number: 6767783
    Abstract: A method of making vertical diodes and transistors in SiC is provided. The method according to the invention uses a mask (e.g., a mask that has been previously used for etching features into the device) for selective epitaxial growth or selective ion implantation. In this manner, the gate and base regions of static induction transistors and bipolar junction transistors can be formed in a self-aligned process. A method of making planar diodes and planar edge termination structures (e.g., guard rings) is also provided.
    Type: Grant
    Filed: July 12, 2002
    Date of Patent: July 27, 2004
    Assignee: Mississippi State University-Research and Technology Corporation (RTC)
    Inventors: Jeffrey B. Casady, Geoffrey E. Carter, Yaroslav Koshka, Michael S. Mazzola, Igor Sankin
  • Publication number: 20030034495
    Abstract: A method of making vertical diodes and transistors in SiC is provided. The method according to the invention uses a mask (e.g., a mask that has been previously used for etching features into the device) for selective epitaxial growth or selective ion implantation. In this manner, the gate and base regions of static induction transistors and bipolar junction transistors can be formed in a self-aligned process. A method of making planar diodes and planar edge termination structures (e.g., guard rings) is also provided.
    Type: Application
    Filed: July 12, 2002
    Publication date: February 20, 2003
    Inventors: Jeffrey B. Casady, Geoffrey E. Carter, Yaroslav Koshka, Michael S. Mazzola, Igor Sankin
  • Publication number: 20020149021
    Abstract: A silicon carbide semi-insulating epitaxy layer is used to create power devices and integrated circuits having significant performance advantages over conventional devices. A silicon carbide semi-insulating layer is formed on a substrate, such as a conducting substrate, and one or more semiconducting devices are formed on the silicon carbide semi-insulating layer. The silicon carbide semi-insulating layer, which includes, for example, 4H or 6H silicon carbide, is formed using a compensating material, the compensating material being selected depending on preferred characteristics for the semi-insulating layer. The compensating material includes, for example, boron, vanadium, chromium, or germanium. Use of a silicon carbide semi-insulating layer provides insulating advantages and improved thermal performance for high power and high frequency semiconductor applications.
    Type: Application
    Filed: January 3, 2002
    Publication date: October 17, 2002
    Inventors: Jeffrey B. Casady, Michael Mazzola
  • Patent number: 6410396
    Abstract: Devices and methods for fabricating wholly silicon carbide heterojunction bipolar transistors (HBTs) using germanium base doping to produce suitable emitter/base heterojunctions. In one variation, all device layers are are grown epitaxially and the heterojunction is created by introducing a pseudoalloying material, such as germanium, to form a graded implant. In other variations, the device epitaxial layers are 1) grown directly onto a semi-insulating substrate, 2) the semi-insulating epitaxial layer is grown onto a conducting substrate; 3) the subcollector is grown on a lightly doped p-type epitaxial layer grown on a conducting substrate; and 4) the subcollector is grown directly on a conducting substrate. Another variation comprises a multi-finger HBT with bridging conductor connections among emitter fingers. Yet another variation includes growth of layers using dopants other than nitrogent or aluminum.
    Type: Grant
    Filed: April 4, 2001
    Date of Patent: June 25, 2002
    Assignee: Mississippi State University
    Inventors: Jeffrey B. Casady, Michael S. Mazzola, Stephen E. Saddow
  • Publication number: 20020076890
    Abstract: Devices and methods for fabricating wholly silicon carbide heterojunction bipolar transistors (HBTs) using germanium base doping to produce suitable emitter/base heterojunctions. In one variation, all device layers are are grown epitaxially and the heterojunction is created by introducing a pseudoalloying material, such as germanium, to form a graded implant. In other variations, the device epitaxial layers are 1) grown directly onto a semi-insulating substrate, 2) the semi-insulating epitaxial layer is grown onto a conducting substrate; 3) the subcollector is grown on a lightly doped p-type epitaxial layer grown on a conducting substrate; and 4) the subcollector is grown directly on a conducting substrate. Another variation comprises a multi-finger HBT with bridging conductor connections among emitter fingers. Yet another variation includes growth of layers using dopants other than nitrogent or aluminum.
    Type: Application
    Filed: April 4, 2001
    Publication date: June 20, 2002
    Inventors: Jeffrey B. Casady, Michael S. Mazzola, Stephen E. Saddow