Patents by Inventor Karl D. Hobart

Karl D. Hobart 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).

  • Publication number: 20190252501
    Abstract: A device structure and method for improving thermal management in highly scaled, high power electronic and optoelectronic devices such as GaN FET and AlGaN/GaN HEMT devices by implementing diamond air bridges into such devices to remove waste heat. The diamond air bridge can be formed from a polycrystalline diamond material layer which can be grown on the surface of a dielectric material layer, on the surface of a III-nitride material, or on the surface of a diamond polycrystalline nucleation layer, and may be optimized to have a high thermal conductivity at the growth interface with the underlying material.
    Type: Application
    Filed: April 23, 2019
    Publication date: August 15, 2019
    Inventors: Karl D. Hobart, Andrew D. Koehler, Francis J. Kub, Travis J. Anderson, Tatyana I. Feygelson, Marko J. Tadjer, Lunet E. Luna
  • Patent number: 10343900
    Abstract: Material structures and methods for etching hexagonal, single-crystal silicon carbide (SiC) materials are provided, which include selection of on-axis or near on-axis hexagonal single-crystal SiC material as the material to be etched. The methods include etching of SiC bulk substrate material, etching of SiC material layers bonded to a silicon oxide layer, etching of suspended SiC material layers, and etching of a SiC material layer anodically bonded to a glass layer. Plasma-etched hexagonal single-crystal SiC materials of the invention may be used to form structures that include, but are not limited to, microelectromechanical beams, microelectromechanical membranes, microelectromechanical cantilevers, microelectromechanical bridges, and microelectromechanical field effect transistor devices.
    Type: Grant
    Filed: September 7, 2017
    Date of Patent: July 9, 2019
    Assignee: The Government of the United States of America, as represented by the Secretary of the Navy
    Inventors: Eugene A. Imhoff, Francis J. Kub, Karl D. Hobart, Rachael L. Myers-Ward
  • Patent number: 10317210
    Abstract: According to one aspect, embodiments herein provide a gyroscope comprising an axially symmetric structure, and a plurality of transducers, each configured to perform at least one of driving and sensing motion of the axially symmetric structure, wherein the plurality of transducers is configured to drive the axially symmetric structure in at least a first vibratory mode and a second vibratory mode, and wherein the gyroscope is implemented on a hexagonal crystal-based substrate.
    Type: Grant
    Filed: May 20, 2016
    Date of Patent: June 11, 2019
    Assignees: THE CHARLES STARK DRAPER LABORATORY, INC., The United States of America, as represented by the Secretary of the Navy
    Inventors: Francis J. Kub, Karl D. Hobart, Eugene Imhoff, Rachael Myers-Ward, Eugene H. Cook, Marc S. Weinberg, Jonathan J. Bernstein
  • Patent number: 10312175
    Abstract: A device structure and method for improving thermal management in highly scaled, high power electronic and optoelectronic devices such as GaN FET and AlGaN/GaN HEMT devices by implementing diamond air bridges into such devices to remove waste heat. The diamond air bridge can be formed from a polycrystalline diamond material layer which can be grown on the surface of a dielectric material layer, on the surface of a III-nitride material, or on the surface of a diamond polycrystalline nucleation layer, and may be optimized to have a high thermal conductivity at the growth interface with the underlying material.
    Type: Grant
    Filed: April 5, 2018
    Date of Patent: June 4, 2019
    Assignee: The United States of America, as represented by the Secretary of the Navy
    Inventors: Karl D. Hobart, Andrew D. Koehler, Francis J. Kub, Travis J. Anderson, Tatyana I. Feygelson, Marko J. Tadjer, Lunet E. Luna
  • Publication number: 20190157181
    Abstract: A device structure and method for improving thermal management in highly scaled, high power electronic and optoelectronic devices such as GaN FET and AlGaN/GaN HEMT devices by implementing diamond air bridges into such devices to remove waste heat. The diamond air bridge can be formed from a polycrystalline diamond material layer which can be grown on the surface of a dielectric material layer, on the surface of a III-nitride material, or on the surface of a diamond polycrystalline nucleation layer, and may be optimized to have a high thermal conductivity at the growth interface with the underlying material.
    Type: Application
    Filed: April 5, 2018
    Publication date: May 23, 2019
    Applicant: The Government of the United States of America, as represented by the Secretary of the Navy
    Inventors: Karl D. Hobart, Andrew D. Koehler, Francis J. Kub, Travis J. Anderson, Tatyana I. Feygelson, Marko J. Tadjer, Lunet E. Luna
  • Patent number: 10229839
    Abstract: An method of annealing by: providing a substrate having a III-nitride, sapphire, silicon, diamond, gallium arsenide, or silicon carbide surface; depositing a layer of a transition metal nitride directly on the surface; and annealing the substrate at at least 900° C. in an oxygen-free environment. An article having: a substrate having a III-nitride, sapphire, silicon, diamond, gallium arsenide, or silicon carbide surface; and a layer of a transition metal nitride directly on the surface.
    Type: Grant
    Filed: May 1, 2017
    Date of Patent: March 12, 2019
    Assignee: The United States of America, as Represented by the Secretary of the Navy
    Inventors: Travis J. Anderson, Boris N. Feygelson, Andrew D. Koehler, Karl D. Hobart, Francis J. Kub, Jordan Greenlee
  • Publication number: 20180374944
    Abstract: A high electron mobility transistor (HEMT) and method of producing the same are provided. The HEMT includes a barrier layer formed on a GaN layer. The HEMT also includes a ZrO2 gate dielectric layer formed by either a ZTB precursor, a TDMA-Zr precursor, or both. The HEMT may also include a recess in the barrier layer in the gate region of the HEMT. The HEMTs may operate in an enhancement mode.
    Type: Application
    Filed: June 25, 2018
    Publication date: December 27, 2018
    Inventors: Travis J. Anderson, Virginia D. Wheeler, Karl D. Hobart, Francis J. Kub
  • Publication number: 20180315820
    Abstract: Current conducting devices and methods for their formation are disclosed. Described are vertical current devices that include a substrate, an n-type material layer, a plurality of p-type gates, and a source. The n-type material layer disposed on the substrate and includes a current channel. A plurality of p-type gates are disposed on opposite sides of the current channel. A source is disposed on a distal side of the current channel with respect to the substrate. The n-type material layer comprises beta-gallium oxide.
    Type: Application
    Filed: April 27, 2018
    Publication date: November 1, 2018
    Inventors: Francis J. Kub, Travis J. Anderson, Marko J. Tadjer, Andrew D. Koehler, Karl D. Hobart
  • Publication number: 20180244513
    Abstract: A structure and method of fabricating suspended beam silicon carbide MEMS structure with low capacitance and good thermal expansion match. A suspended material structure is attached to an anchor material structure that is direct wafer bonded to a substrate. The anchor material structure and the suspended material structure are formed from either a hexagonal single-crystal SiC material, and the anchor material structure is bonded to the substrate while the suspended material structure does not have to be attached to the substrate. The substrate may be a semi-insulating or insulating SiC substrate. The substrate may have an etched recess region on the substrate first surface to facilitate the formation of the movable suspended material structures. The substrate may have patterned electrical electrodes on the substrate first surface, within recesses etched into the substrate.
    Type: Application
    Filed: February 28, 2018
    Publication date: August 30, 2018
    Applicant: The Government of the United States of America, as represented by the Secretary of the Navy
    Inventors: Francis J. Kub, Karl D. Hobart, Eugene A. Imhoff, Rachael L. Myers-Ward
  • Patent number: 10002958
    Abstract: Systems and method are provided for depositing metal on GaN transistors after gate formation using a metal nitride Schottky gate. Embodiments of the present disclosure use a “diamond last” process using thermally stable metal nitride gate electrodes to enable thicker heat spreading films and facilitate process integration. In an embodiment, the “diamond last” process with high thermal conductivity diamond is enabled by the integration of thermally stable metal-nitride gate electrodes.
    Type: Grant
    Filed: June 8, 2017
    Date of Patent: June 19, 2018
    Assignee: The United States of America, as represented by the Secretary of the Navy
    Inventors: Francis J. Kub, Travis J. Anderson, Virginia D. Wheeler, Andrew D. Koehler, Karl D. Hobart
  • Patent number: 9991354
    Abstract: Systems and methods are provided that enable the production of semiconductor devices having a metal nitride layer in direct contact with a semiconductor layer to form a Schottky diode, such as a TiN gate on an AlGaN/GaN high electron mobility transistor (HEMT). Metal nitrides offer exceptional thermal stability and a lower diffusion coefficient. Technology enabled by embodiments of the present disclosure improves the reliability of GaN-based microwave power transistors.
    Type: Grant
    Filed: May 16, 2017
    Date of Patent: June 5, 2018
    Assignee: The United States of America, as represented by the Secretary of the Navy
    Inventors: Travis J. Anderson, Virginia D. Wheeler, David Shahin, Andrew D. Koehler, Karl D. Hobart, Francis J. Kub, Marko J. Tadjer
  • Patent number: 9960266
    Abstract: Passivated AlGaN/GaN HEMTs having no plasma damage to the AlGaN surface and methods for making the same. In a first embodiment, a thin HF SiN barrier layer is deposited on the AlGaN surface after formation of the gate. A thick HF/LF SiN layer is then deposited, the thin HF SiN layer and the thick HF/LF Sin layer comprising bi-layer SiN passivation on the HEMT. In a second embodiment, a first thin HF SiN barrier layer is deposited on the AlGaN surface before formation of the gate and is annealed. Following annealing of the first SiN layer, the gate is formed, and a second HF SiN barrier layer is deposited, followed by a thick HF/LF SiN layer, the three SiN layers comprising tri-layer SiN passivation on the HEMT.
    Type: Grant
    Filed: May 11, 2017
    Date of Patent: May 1, 2018
    Assignee: The United States of America, as represented by the Secretary of the Navy
    Inventors: Marko J. Tadjer, Andrew D. Koehler, Travis J. Anderson, Karl D. Hobart
  • Publication number: 20180086625
    Abstract: Electromechanical device structures are provided, as well as methods for forming them. The device structures incorporate at least a first and second substrate separated by an interface material layer, where the first substrate comprises an anchor material structure and at least one suspended material structure, optionally a spring material structure, and optionally an electrostatic sense electrode. The device structures may be formed by methods that include providing an interface material layer on one or both of the first and second substrates, bonding the interface materials to the opposing first or second substrate or to the other interface material layer, followed by forming the suspended material structure by etching.
    Type: Application
    Filed: September 7, 2017
    Publication date: March 29, 2018
    Applicants: The Government of the United States of America, as Represented by the Secretary of the Navy, The Charles Stark Draper Laboratory, Inc.
    Inventors: Francis J. KUB, Karl D. HOBART, Eugene A. IMHOFF, Rachael L. MYERS-WARD, Eugene COOK, Jonathan BERNSTEIN, Marc WEINBERG
  • Publication number: 20180065844
    Abstract: Material structures and methods for etching hexagonal, single-crystal silicon carbide (SiC) materials are provided, which include selection of on-axis or near on-axis hexagonal single-crystal SiC material as the material to be etched. The methods include etching of SiC bulk substrate material, etching of SiC material layers bonded to a silicon oxide layer, etching of suspended SiC material layers, and etching of a SiC material layer anodically bonded to a glass layer. Plasma-etched hexagonal single-crystal SiC materials of the invention may be used to form structures that include, but are not limited to, microelectromechanical beams, microelectromechanical membranes, microelectromechanical cantilevers, microelectromechanical bridges, and microelectromechanical field effect transistor devices.
    Type: Application
    Filed: September 7, 2017
    Publication date: March 8, 2018
    Applicant: The Government of the United States of America, as Represented by the Secretary of the Navy
    Inventors: Eugene A. IMHOFF, Francis J. KUB, Karl D. HOBART, Rachael L. MYERS-WARD
  • Publication number: 20170358670
    Abstract: Systems and method are provided for depositing metal on GaN transistors after gate formation using a metal nitride Schottky gate. Embodiments of the present disclosure use a “diamond last” process using thermally stable metal nitride gate electrodes to enable thicker heat spreading films and facilitate process integration. In an embodiment, the “diamond last” process with high thermal conductivity diamond is enabled by the integration of thermally stable metal-nitride gate electrodes.
    Type: Application
    Filed: June 8, 2017
    Publication date: December 14, 2017
    Inventors: Francis J. Kub, Travis J. Anderson, Virginia D. Wheeler, Andrew D. Koehler, Karl D. Hobart
  • Publication number: 20170338332
    Abstract: Passivated AlGaN/GaN HEMTs having no plasma damage to the AlGaN surface and methods for making the same. In a first embodiment, a thin HF SiN barrier layer is deposited on the AlGaN surface after formation of the gate. A thick HF/LF SiN layer is then deposited, the thin HF SiN layer and the thick HF/LF Sin layer comprising bi-layer SiN passivation on the HEMT. In a second embodiment, a first thin HF SiN barrier layer is deposited on the AlGaN surface before formation of the gate and is annealed. Following annealing of the first SiN layer, the gate is formed, and a second HF SiN barrier layer is deposited, followed by a thick HF/LF SiN layer, the three SiN layers comprising tri-layer SiN passivation on the HEMT.
    Type: Application
    Filed: May 11, 2017
    Publication date: November 23, 2017
    Applicant: The Government of the United States of America, as represented by the Secretary of the Navy
    Inventors: Marko J. Tadjer, Andrew D. Koehler, Travis J. Anderson, Karl D. Hobart
  • Publication number: 20170330950
    Abstract: Systems and methods are provided that enable the production of semiconductor devices having a metal nitride layer in direct contact with a semiconductor layer to form a Schottky diode, such as a TiN gate on an AlGaN/GaN high electron mobility transistor (HEMT). Metal nitrides offer exceptional thermal stability and a lower diffusion coefficient. Technology enabled by embodiments of the present disclosure improves the reliability of GaN-based microwave power transistors.
    Type: Application
    Filed: May 16, 2017
    Publication date: November 16, 2017
    Inventors: Travis J. Anderson, Virginia D. Wheeler, David Shahin, Andrew D. Koehler, Karl D. Hobart, Francis J. Kub, Marko J. Tadjer
  • Publication number: 20170316952
    Abstract: An method of annealing by: providing a substrate having a III-nitride, sapphire, silicon, diamond, gallium arsenide, or silicon carbide surface; depositing a layer of a transition metal nitride directly on the surface; and annealing the substrate at at least 900° C. in an oxygen-free environment. An article having: a substrate having a III-nitride, sapphire, silicon, diamond, gallium arsenide, or silicon carbide surface; and a layer of a transition metal nitride directly on the surface.
    Type: Application
    Filed: May 1, 2017
    Publication date: November 2, 2017
    Applicant: The Government of the United States of America, as represented by the Secretary of the Navy
    Inventors: Travis J. Anderson, Boris N. Feygelson, Andrew D. Koehler, Karl D. Hobart, Francis J. Kub, Jordan Greenlee
  • Patent number: 9685513
    Abstract: Semiconductor devices that include a semiconductor structure integrated with one or more diamond material layers. A first diamond material layer is formed on a bottom surface and optionally, the side surfaces of the semiconductor structure. In some embodiments, at least a portion of the semiconductor structure is embedded in the diamond. An electrical device can be formed on a top surface of the semiconductor structure. A second diamond material layer can be formed on the top surface of the semiconductor structure. The semiconductor structure can include a III-nitride material such as GaN, which can be embedded within a the first diamond material layer or encased by the first and/or second diamond material layer.
    Type: Grant
    Filed: October 23, 2013
    Date of Patent: June 20, 2017
    Assignee: The United States of America, as represented by the Secretary of the Navy
    Inventors: Francis J. Kub, Travis J. Anderson, Karl D. Hobart
  • Publication number: 20160341552
    Abstract: According to one aspect, embodiments herein provide a gyroscope comprising an axially symmetric structure, and a plurality of transducers, each configured to perform at least one of driving and sensing motion of the axially symmetric structure, wherein the plurality of transducers is configured to drive the axially symmetric structure in at least a first vibratory mode and a second vibratory mode, and wherein the gyroscope is implemented on a hexagonal crystal-based substrate.
    Type: Application
    Filed: May 20, 2016
    Publication date: November 24, 2016
    Inventors: Francis J. Kub, Karl D. Hobart, Eugene Imhoff, Rachael Myers-Ward, Eugene H. Cook, Marc S. Weinberg, Jonathan J. Bernstein