Patents by Inventor Walter R. Buchanan

Walter R. Buchanan 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: 20090297409
    Abstract: The present invention is generally directed to a single or dual dielectric barrier discharge reactor for generating flow discharge plasmas at atmospheric pressure or higher pressures. In particular, the present invention relates to a providing stable, energy efficient, glow discharge plasmas having a controlled discharge gap.
    Type: Application
    Filed: May 30, 2008
    Publication date: December 3, 2009
    Inventors: Walter R. Buchanan, Christopher D. Hruska
  • Patent number: 6797992
    Abstract: The present invention provides a high voltage semiconductor device capable of withstanding excessive breakdown and clamping voltages. The device includes a high resistivity substrate, and an epitaxially grown, low resistivity layer having a stress-relieving dopant. During production, the low conductivity region has one surface that is etched before a high conductivity region is diffused into it or epitaxially deposited on it.
    Type: Grant
    Filed: August 7, 2001
    Date of Patent: September 28, 2004
    Assignee: FabTech, Inc.
    Inventors: Roman J. Hamerski, Walter R. Buchanan
  • Patent number: 6717229
    Abstract: A diode (20), having first and second conductive layers (24,26), a conductive pad (28), and a distributed reverse surge guard (22), provides increased protection from reverse current surges. The surge guard (22) includes an outer loop (42) of P+-type surge guard material and an inner grid (44) of linear sections (46, 48) which form a plurality of inner loops extending inside the outer loop (42). The surge guard (22) distributes any reverse current over the area of the conductive pad (28) to provide increased protection from transient threats such as electrostatic discharge (ESD) and during electrical testing.
    Type: Grant
    Filed: March 11, 2002
    Date of Patent: April 6, 2004
    Assignee: Fabtech, Inc.
    Inventors: Walter R. Buchanan, Roman J. Hamerski, Wayne A. Smith
  • Patent number: 6710419
    Abstract: An improved Schottky device, having a low resistivity layer of semiconductor material, a high resistivity layer of semiconductor material and a buried dopant region positioned in the high resistivity layer utilized to reduce reverse leakage current. The low resistivity layer can be an N+ material while the high resistivity layer can be an N− layer. The buried dopant region can be of P+ material, thus forming a PN junction with an associated charge depletion zone in the N− layer and an associated low reverse leakage current. The location of the P+ material allows for a full Schottky barrier between the N− material and a barrier metal to be maintained, thus the device experiences a low forward voltage drop.
    Type: Grant
    Filed: August 29, 2002
    Date of Patent: March 23, 2004
    Assignee: Fabtech, Inc.
    Inventors: Walter R. Buchanan, Roman J. Hamerski
  • Publication number: 20040046228
    Abstract: The present invention provides a high voltage semiconductor device capable of withstanding excessive breakdown and clamping voltages. The device includes a high resistivity substrate, and an epitaxially grown, low resistivity layer having a stress-relieving dopant. During production, the low conductivity region has one surface that is etched before a high conductivity region is diffused into it or epitaxially deposited on it.
    Type: Application
    Filed: August 13, 2003
    Publication date: March 11, 2004
    Inventors: Roman J. Hamerski, Walter R. Buchanan
  • Publication number: 20030030069
    Abstract: The present invention provides a high voltage semiconductor device capable of withstanding excessive breakdown and clamping voltages. The device includes a high resistivity substrate, and an epitaxially grown, low resistivity layer having a stress-relieving dopant. During production, the low conductivity region has one surface that is etched before a high conductivity region is diffused into it or epitaxially deposited on it.
    Type: Application
    Filed: August 7, 2001
    Publication date: February 13, 2003
    Inventors: Roman J. Hamerski, Walter R. Buchanan
  • Publication number: 20030006472
    Abstract: An improved Schottky device, having a low resistivity layer of semiconductor material, a high resistivity layer of semiconductor material and a buried dopant region positioned in the high resistivity layer utilized to reduce reverse leakage current. The low resistivity layer can be an N+ material while the high resistivity layer can be an N− layer. The buried dopant region can be of P+ material, thus forming a PN junction with an associated charge depletion zone in the N− layer and an associated low reverse leakage current. The location of the P+ material allows for a full Schottky barrier between the N− material and a barrier metal to be maintained, thus the device experiences a low forward voltage drop.
    Type: Application
    Filed: August 29, 2002
    Publication date: January 9, 2003
    Inventors: Walter R. Buchanan, Roman J. Hamerski
  • Patent number: 6500741
    Abstract: An electrical device such as a diode usable in high voltage applications wherein the electrical device is fabricated from a method which yields a plurality of high voltage electrical devices, the present method including providing a substrate of a semiconductor material having a predetermined substrate conductive type, the substrate being typically formed from a monocrystalline growth method, forming a second epitaxial layer contiguous with the upper surface of the substrate, the epitaxial layer having a predetermined second layer conductive type, and thereafter forming a top layer of dopant material in a predetermined pattern upon the upper surface of the second epitaxial layer. This predetermined pattern of dopant material typically takes the form of an array of patches which can be achieved through either a masking and etching process, or through a screen printing process.
    Type: Grant
    Filed: March 28, 2002
    Date of Patent: December 31, 2002
    Assignee: Fabtech, Inc.
    Inventors: Walter R. Buchanan, Roman J. Hamerski
  • Patent number: 6479885
    Abstract: An electrical device such as a diode usable in high voltage applications wherein the electrical device is fabricated from a method which yields a plurality of high voltage electrical devices, the present method including providing a substrate of a semiconductor material having a predetermined substrate conductive type, the substrate being typically formed from a monocrystalline growth method, forming a second epitaxial layer contiguous with the upper surface of the substrate, the epitaxial layer having a predetermined second layer conductive type, and thereafter forming a top layer of dopant, material in a predetermined pattern upon the upper surface of the second epitaxial layer. This predetermined pattern of dopant material typically takes the form of an array of patches which can be achieved through either a masking and etching process, or through a screen printing process.
    Type: Grant
    Filed: March 28, 2002
    Date of Patent: November 12, 2002
    Assignee: Fabtech, Inc.
    Inventors: Walter R. Buchanan, Roman J. Hamerski
  • Patent number: 6462393
    Abstract: An improved Schottky device, having a low resistivity layer of semiconductor material, a high resistivity layer of semiconductor material and a buried dopant region positioned in the high resistivity layer utilized to reduce reverse leakage current. The low resistivity layer can be an N+ material while the high resistivity layer can be an N− layer. The buried dopant region can be of P+ material, thus forming a PN junction with an associated charge depletion zone in the N− layer and an associated low reverse leakage current. The location of the P+ material allows for a full Schottky barrier between the N− material and a barrier metal to be maintained, thus the device experiences a low forward voltage drop.
    Type: Grant
    Filed: March 20, 2001
    Date of Patent: October 8, 2002
    Assignee: FabTech, Inc.
    Inventors: Walter R. Buchanan, Roman J. Hamerski
  • Publication number: 20020135038
    Abstract: An improved Schottky device, having a low resistivity layer of semiconductor material, a high resistivity layer of semiconductor material and a buried dopant region positioned in the high resistivity layer utilized to reduce reverse leakage current. The low resistivity layer can be an N+ material while the high resistivity layer can be an N− layer. The buried dopant region can be of P+ material, thus forming a PN junction with an associated charge depletion zone in the N− layer and an associated low reverse leakage current. The location of the P+ material allows for a full Schottky barrier between the N− material and a barrier metal to be maintained, thus the device experiences a low forward voltage drop.
    Type: Application
    Filed: March 20, 2001
    Publication date: September 26, 2002
    Inventors: Walter R. Buchanan, Roman J. Hamerski
  • Publication number: 20020105055
    Abstract: An electrical device such as a diode usable in high voltage applications wherein the electrical device is fabricated from a method which yields a plurality of high voltage electrical devices, the present method including providing a substrate of a semiconductor material having a predetermined substrate conductive type, the substrate being typically formed from a monocrystalline growth method, forming a second epitaxial layer contiguous with the upper surface of the substrate, the epitaxial layer having a predetermined second layer conductive type, and thereafter forming a top layer of dopant material in a predetermined pattern upon the upper surface of the second epitaxial layer. This predetermined pattern of dopant material typically takes the form of an array of patches which can be achieved through either a masking and etching process, or through a screen printing process.
    Type: Application
    Filed: March 28, 2002
    Publication date: August 8, 2002
    Inventors: Walter R. Buchanan, Roman J. Hamerski
  • Publication number: 20020105044
    Abstract: A diode (20), having first and second conductive layers (24,26), a conductive pad (28), and a distributed reverse surge guard (22), provides increased protection from reverse current surges. The surge guard (22) includes an outer loop (42) of P+-type surge guard material and an inner grid (44) of linear sections (46, 48) which form a plurality of inner loops extending inside the outer loop (42). The surge guard (22) distributes any reverse current over the area of the conductive pad (28) to provide increased protection from transient threats such as electrostatic discharge (ESD) and during electrical testing.
    Type: Application
    Filed: March 11, 2002
    Publication date: August 8, 2002
    Inventors: Walter R. Buchanan, Roman J. Hamerski, Wayne A. Smith
  • Publication number: 20020098632
    Abstract: An electrical device such as a diode usable in high voltage applications wherein the electrical device is fabricated from a method which yields a plurality of high voltage electrical devices, the present method including providing a substrate of a semiconductor material having a predetermined substrate conductive type, the substrate being typically formed from a monocrystalline growth method, forming a second epitaxial layer contiguous with the upper surface of the substrate, the epitaxial layer having a predetermined second layer conductive type, and thereafter forming a top layer of dopant material in a predetermined pattern upon the upper surface of the second epitaxial layer. This predetermined pattern of dopant material typically takes the form of an array of patches which can be achieved through either a masking and etching process, or through a screen printing process.
    Type: Application
    Filed: March 28, 2002
    Publication date: July 25, 2002
    Inventors: Walter R. Buchanan, Roman J. Hamerski
  • Patent number: 6376346
    Abstract: An electrical device such as a diode usable in high voltage applications wherein the electrical device is fabricated from a method which yields a plurality of high voltage electrical devices, the present method including providing a substrate of a semiconductor material having a predetermined substrate conductive type, the substrate being typically formed from a monocrystalline growth method, forming a second epitaxial layer contiguous with the upper surface of the substrate, the epitaxial layer having a predetermined second layer conductive type, and thereafter forming a top layer of dopant material in a predetermined pattern upon the upper surface of the second epitaxial layer. This predetermined pattern of dopant material typically takes the form of an array of patches which can be achieved through either a masking and etching process, or through a screen printing process.
    Type: Grant
    Filed: September 28, 2000
    Date of Patent: April 23, 2002
    Assignee: FabTech, Inc.
    Inventors: Walter R. Buchanan, Roman J. Hamerski
  • Patent number: 5017508
    Abstract: A method and apparatus for annealing devices having radiation induced damage is disclosed. A device is exposed to electron irradiation to induce damage to the active area. The device is then annealed with a rapid thermal anneal at a low temperature. The rapid thermal anneal may, optionally, be followed by a conventional oven or furnace anneal at a temperature of about 300.degree. to 450.degree. C. The method produces devices having improved and well controlled characteristics such as short circuit operating area, power dissipated during switching, and on-state voltage drop.
    Type: Grant
    Filed: June 29, 1989
    Date of Patent: May 21, 1991
    Assignee: Ixys Corporation
    Inventors: Darcy T. Dodt, Walter R. Buchanan