Patents by Inventor Howard Tweddle

Howard Tweddle 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: 10283501
    Abstract: A GaN-on-Si device structure and a method of fabrication are disclosed for improved die yield and device reliability of high current/high voltage lateral GaN transistors. A plurality of conventional GaN device structures comprising GaN epi-layers are fabricated on a silicon substrate (GaN-on-Si die). After processing of on-chip interconnect layers, a trench structure is defined around each die, through the GaN epi-layers and into the silicon substrate. A trench cladding is provided on proximal sidewalls, comprising at least one of a passivation layer and a conductive metal layer. The trench cladding extends over exposed surfaces of the GaN epi-layers, over the interface region with the substrate, and also over the exposed surfaces of the interconnect layers. This structure reduces risk of propagation of dicing damage and defects or cracks in the GaN epi-layers into active device regions. A metal trench cladding acts as a barrier for electro-migration of mobile ions.
    Type: Grant
    Filed: March 2, 2017
    Date of Patent: May 7, 2019
    Assignee: GaN Systems Inc.
    Inventors: Thomas Macelwee, Greg P. Klowak, Howard Tweddle
  • Patent number: 10249506
    Abstract: A GaN-on-Si device structure and a method of fabrication are disclosed for improved die yield and device reliability of high current/high voltage lateral GaN transistors. A plurality of conventional GaN device structures comprising GaN epi-layers are fabricated on a silicon substrate (GaN-on-Si die). After processing of on-chip interconnect layers, a trench structure is defined around each die, through the GaN epi-layers and into the silicon substrate. A trench cladding is provided on proximal sidewalls, comprising at least one of a passivation layer and a conductive metal layer. The trench cladding extends over exposed surfaces of the GaN epi-layers, over the interface region with the substrate, and over the exposed surfaces of the interconnect layers. This structure reduces risk of propagation of dicing damage and defects or cracks in the GaN epi-layers into active device regions. A metal trench cladding acts as a barrier for electro-migration of mobile ions.
    Type: Grant
    Filed: September 22, 2017
    Date of Patent: April 2, 2019
    Inventors: Thomas Macelwee, Greg P. Klowak, Howard Tweddle
  • Publication number: 20180012770
    Abstract: A GaN-on-Si device structure and a method of fabrication are disclosed for improved die yield and device reliability of high current/high voltage lateral GaN transistors. A plurality of conventional GaN device structures comprising GaN epi-layers are fabricated on a silicon substrate (GaN-on-Si die). After processing of on-chip interconnect layers, a trench structure is defined around each die, through the GaN epi-layers and into the silicon substrate. A trench cladding is provided on proximal sidewalls, comprising at least one of a passivation layer and a conductive metal layer. The trench cladding extends over exposed surfaces of the GaN epi-layers, over the interface region with the substrate, and over the exposed surfaces of the interconnect layers. This structure reduces risk of propagation of dicing damage and defects or cracks in the GaN epi-layers into active device regions. A metal trench cladding acts as a barrier for electro-migration of mobile ions.
    Type: Application
    Filed: September 22, 2017
    Publication date: January 11, 2018
    Inventors: Thomas MACELWEE, Greg P. KLOWAK, Howard TWEDDLE
  • Patent number: 9818857
    Abstract: A fault tolerant design for large area nitride semiconductor devices is provided, which facilitates testing and isolation of defective areas. A transistor comprises an array of a plurality of islands, each island comprising an active region, source and drain electrodes, and a gate electrode. Electrodes of each island are electrically isolated from electrodes of neighboring islands in at least one direction of the array. Source, drain and gate contact pads are provided to enable electrical testing of each island. After electrical testing of islands to identify defective islands, overlying electrical connections are formed to interconnect source electrodes in parallel, drain electrodes in parallel, and to interconnect gate electrodes to form a common gate electrode of large gate width Wg. Interconnections are provided selectively to good islands, while electrically isolating defective islands. This approach makes it economically feasible to fabricate large area GaN devices, including hybrid devices.
    Type: Grant
    Filed: October 28, 2014
    Date of Patent: November 14, 2017
    Assignee: GaN Systems Inc.
    Inventors: Greg P. Klowak, Cameron McKnight-Macneil, Howard Tweddle, Ahmad Mizan, Nigel Springett
  • Publication number: 20170256638
    Abstract: A GaN-on-Si device structure and a method of fabrication are disclosed for improved die yield and device reliability of high current/high voltage lateral GaN transistors. A plurality of conventional GaN device structures comprising GaN epi-layers are fabricated on a silicon substrate (GaN-on-Si die). After processing of on-chip interconnect layers, a trench structure is defined around each die, through the GaN epi-layers and into the silicon substrate. A trench cladding is provided on proximal sidewalls, comprising at least one of a passivation layer and a conductive metal layer. The trench cladding extends over exposed surfaces of the GaN epi-layers, over the interface region with the substrate, and also over the exposed surfaces of the interconnect layers. This structure reduces risk of propagation of dicing damage and defects or cracks in the GaN epi-layers into active device regions. A metal trench cladding acts as a barrier for electro-migration of mobile ions.
    Type: Application
    Filed: March 2, 2017
    Publication date: September 7, 2017
    Inventors: Thomas MACELWEE, Greg P. KLOWAK, Howard TWEDDLE
  • Publication number: 20160284829
    Abstract: A fault tolerant design for large area nitride semiconductor devices is provided, which facilitates testing and isolation of defective areas. A transistor comprises an array of a plurality of islands, each island comprising an active region, source and drain electrodes, and a gate electrode. Electrodes of each island are electrically isolated from electrodes of neighbouring islands in at least one direction of the array. Source, drain and gate contact pads are provided to enable electrical testing of each island. After electrical testing of islands to identify defective islands, overlying electrical connections are formed to interconnect source electrodes in parallel, drain electrodes in parallel, and to interconnect gate electrodes to form a common gate electrode of large gate width Wg. Interconnections are provided selectively to good islands, while electrically isolating defective islands. This approach makes it economically feasible to fabricate large area GaN devices, including hybrid devices.
    Type: Application
    Filed: October 28, 2014
    Publication date: September 29, 2016
    Inventors: Greg P. KLOWAK, Cameron MCKNIGHT-MACNEIL, Howard TWEDDLE, Ahmad MIZAN, Nigel SPRINGETT
  • Patent number: 9153509
    Abstract: A fault tolerant design for large area nitride semiconductor devices is provided, which facilitates testing and isolation of defective areas. A transistor comprises an array of a plurality of islands, each island comprising an active region, source and drain electrodes, and a gate electrode. Electrodes of each island are electrically isolated from electrodes of neighboring islands in at least one direction of the array. Source, drain and gate contact pads are provided to enable electrical testing of each island. After electrical testing of islands to identify defective islands, overlying electrical connections are formed to interconnect source electrodes in parallel, drain electrodes in parallel, and to interconnect gate electrodes to form a common gate electrode of large gate width Wg. Interconnections are provided selectively to good islands, while electrically isolating defective islands. This approach makes it economically feasible to fabricate large area GaN devices, including hybrid devices.
    Type: Grant
    Filed: December 12, 2014
    Date of Patent: October 6, 2015
    Assignee: GaN Systems Inc.
    Inventors: Gregory P. Klowak, Cameron McKnight-MacNeil, Howard Tweddle, Ahmad Mizan, Nigel Springett
  • Publication number: 20150162252
    Abstract: A fault tolerant design for large area nitride semiconductor devices is provided, which facilitates testing and isolation of defective areas. A transistor comprises an array of a plurality of islands, each island comprising an active region, source and drain electrodes, and a gate electrode. Electrodes of each island are electrically isolated from electrodes of neighboring islands in at least one direction of the array. Source, drain and gate contact pads are provided to enable electrical testing of each island. After electrical testing of islands to identify defective islands, overlying electrical connections are formed to interconnect source electrodes in parallel, drain electrodes in parallel, and to interconnect gate electrodes to form a common gate electrode of large gate width Wg. Interconnections are provided selectively to good islands, while electrically isolating defective islands. This approach makes it economically feasible to fabricate large area GaN devices, including hybrid devices.
    Type: Application
    Filed: December 12, 2014
    Publication date: June 11, 2015
    Applicant: GAN SYSTEMS INC.
    Inventors: Gregory P. KLOWAK, Cameron MCKNIGHT-MACNEIL, Howard TWEDDLE, Ahmad MIZAN, Nigel SPRINGETT
  • Patent number: 7839467
    Abstract: The present invention replaces conventional lighting devices, such as incandescent lamps, fluorescent lamps, and LED lamps, with an integrated electro-luminescent film structure, subdivided into electrically isolated micro-panels. Ideally, the electro-luminescent structure comprises separate red, green and blue micro-panels providing a full range of color adjustment. Alternatively, the electro-luminescent film structure includes stacked groups of layers, in which each group emits a different color and is independently controllable.
    Type: Grant
    Filed: October 16, 2009
    Date of Patent: November 23, 2010
    Assignee: Group IV Semiconductor Inc.
    Inventors: Carla Miner, Thomas MacElwee, Stephen Naor, Howard Tweddle
  • Publication number: 20100033111
    Abstract: The present invention replaces the conventional cold cathode fluorescent tubes used in backlighting units of liquid crystal displays with an integrated electro-luminescent film structure, subdivided into electrically isolated micro-panels. Ideally, the electro-luminescent structure comprises separate red, green and blue micro-panels providing full color capabilities. Alternatively, the electro-luminescent film structure includes stacked groups of layers, in which each group emits a different color and is independently controllable.
    Type: Application
    Filed: October 16, 2009
    Publication date: February 11, 2010
    Inventors: Carla Miner, Thomas MacElwee, Stephen Naor, Howard Tweddle
  • Patent number: 7616272
    Abstract: The present invention replaces the conventional cold cathode fluorescent tubes used in backlighting units of liquid crystal displays with an integrated electro-luminescent film structure, subdivided into electrically isolated micro-panels. Ideally, the electro-luminescent structure comprises separate red, green and blue micro-panels providing full color capabilities. Alternatively, the electro-luminescent film structure includes stacked groups of layers, in which each group emits a different color and is independently controllable.
    Type: Grant
    Filed: August 17, 2007
    Date of Patent: November 10, 2009
    Assignee: Group IV Semiconductor Inc.
    Inventors: Carla Miner, Thomas MacElwee, Stephen Naor, Howard Tweddle
  • Publication number: 20090046222
    Abstract: The present invention replaces the conventional cold cathode fluorescent tubes used in backlighting units of liquid crystal displays with an integrated electro-luminescent film structure, subdivided into electrically isolated micro-panels. Ideally, the electro-luminescent structure comprises separate red, green and blue micro-panels providing full color capabilities. Alternatively, the electro-luminescent film structure includes stacked groups of layers, in which each group emits a different color and is independently controllable.
    Type: Application
    Filed: August 17, 2007
    Publication date: February 19, 2009
    Inventors: Carla Miner, Thomas MacElwee, Stephen Naor, Howard Tweddle
  • Patent number: RE49603
    Abstract: A GaN-on-Si device structure and a method of fabrication are disclosed for improved die yield and device reliability of high current/high voltage lateral GaN transistors. A plurality of conventional GaN device structures comprising GaN epi-layers are fabricated on a silicon substrate (GaN-on-Si die). After processing of on-chip interconnect layers, a trench structure is defined around each die, through the GaN epi-layers and into the silicon substrate. A trench cladding is provided on proximal sidewalls, comprising at least one of a passivation layer and a conductive metal layer. The trench cladding extends over exposed surfaces of the GaN epi-layers, over the interface region with the substrate, and also over the exposed surfaces of the interconnect layers. This structure reduces risk of propagation of dicing damage and defects or cracks in the GaN epi-layers into active device regions. A metal trench cladding acts as a barrier for electro-migration of mobile ions.
    Type: Grant
    Filed: May 7, 2020
    Date of Patent: August 8, 2023
    Assignee: GAN SYSTEMS INC.
    Inventors: Thomas Macelwee, Greg P. Klowak, Howard Tweddle