Patents by Inventor Matthew Francis O'Keefe

Matthew Francis O'Keefe 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: 20140287590
    Abstract: A method of manufacture of an optical waveguide structure including the steps of: providing a multilayer semiconductor wafer including a III-V semiconductor substrate, a III-V semiconductor top layer and an etch stop layer sandwiched therebetween, the etch stop layer including aluminium and phosphorous; and etching through the top layer to the etch stop layer by use of a dry etch containing chlorine to provide two spaced apart recesses defining the optical waveguide therebetween.
    Type: Application
    Filed: November 25, 2013
    Publication date: September 25, 2014
    Applicant: U2T Photonics UK Limited
    Inventors: Gayle Murdoch, Matthew Francis O'Keefe, Stephen John Clements
  • Patent number: 8405068
    Abstract: A reflecting light emitting structure includes a substrate having a plurality of grooves formed in a first face of the substrate is disclosed. The first face is in a first crystallographic plane. Each of the plurality of grooves includes a first sidewall that is coplanar with a second crystallographic plane and a second sidewall that is coplanar with a third crystallographic plane. A buffer layer is provided on the substrate to reduce mechanical strain between the substrate and a light emitting diode (LED) fabricated on the buffer layer.
    Type: Grant
    Filed: July 22, 2010
    Date of Patent: March 26, 2013
    Assignee: RFMD (UK) Limited
    Inventor: Matthew Francis O'Keefe
  • Patent number: 8101973
    Abstract: A heterojunction bipolar transistor comprising a substrate; a collector on the substrate; a base layer on the collector; an emitter layer on the base layer; the emitter layer comprising an upper emitter layer and a lower emitter layer between the upper emitter layer and base; the collector, base and emitter layers being npn or pnp doped respectively; characterized in that the lower emitter layer has a larger bandgap than the base layer and is AlxIn1-xP or GaxAl1-xP, x being in the range 0+ to 1.
    Type: Grant
    Filed: March 27, 2008
    Date of Patent: January 24, 2012
    Assignee: RFMD (UK) Limited
    Inventors: Matthew Francis O'Keefe, Robert Grey, Michael Charles Clausen, Richard Alun Davies
  • Publication number: 20110243520
    Abstract: An optical waveguide structure including a III-V semiconductor substrate, a III-V semiconductor top layer, and an etch stop layer sandwiched therebetween, the etch stop layer containing aluminium and phosphorous, the top layer including first and second spaced apart recesses extending through the top layer to the etch stop layer and defining an optical waveguide therebetween. Also a method of manufacture of an optical waveguide structure including the steps of: providing a multilayer semiconductor wafer including a III-V semiconductor substrate, a III-V semiconductor top layer and an etch stop layer sandwiched therebetween, the etch stop layer including aluminium and phosphorous; and etching through the top layer to the etch stop layer by use of a dry etch containing chlorine to provide two spaced apart recesses defining the optical waveguide therebetween.
    Type: Application
    Filed: July 10, 2008
    Publication date: October 6, 2011
    Inventors: Gayle Murdoch, Matthew Francis O'Keefe, Stephen John Clements
  • Publication number: 20110101300
    Abstract: A reflecting light emitting structure includes a substrate having a plurality of grooves formed in a first face of the substrate is disclosed. The first face is in a first crystallographic plane. Each of the plurality of grooves includes a first sidewall that is coplanar with a second crystallographic plane and a second sidewall that is coplanar with a third crystallographic plane. A buffer layer is provided on the substrate to reduce mechanical strain between the substrate and a light emitting diode (LED) fabricated on the buffer layer.
    Type: Application
    Filed: July 22, 2010
    Publication date: May 5, 2011
    Applicant: RFMD (UK) LIMITED
    Inventor: Matthew Francis O'Keefe
  • Publication number: 20110017972
    Abstract: A light emitting structure having reverse voltage protection (RVP) is provided along with disclosure of a method for fabricating the light emitting structure. The light emitting structure includes a substrate having a first face, a second face, and a p-n junction formed within the substrate between a p-type layer and an n-type layer, wherein the p-type layer and the n-type layer are adapted as a RVP diode. A buffer layer is provided on the substrate, and a light emitting diode (LED) is fabricated on the buffer layer. The LED is then electrically coupled to the RVP diode in an anti-parallel diode pair (APDP) configuration.
    Type: Application
    Filed: July 22, 2010
    Publication date: January 27, 2011
    Applicant: RFMD (UK) LIMITED
    Inventor: Matthew Francis O'Keefe
  • Patent number: 7868356
    Abstract: A III-V field effect transistor comprising a semiconductor channel layer having an electrically conducting channel; an ohmic contact layer on the semiconductor channel layer, the ohmic contact layer having a recess structure disposed therethrough to the semiconductor channel layer; the bottom of the ohmic contact layer comprising an etch stop layer comprising Aluminium and Phosphorous and defining the shape of the recess at its junction with the semiconductor channel layer.
    Type: Grant
    Filed: April 30, 2009
    Date of Patent: January 11, 2011
    Assignee: Filtronic PLC
    Inventors: Matthew Francis O'Keefe, Michael Charles Clausen, Richard Alun Davies, Robert Grey
  • Publication number: 20090261382
    Abstract: A III-V field effect transistor comprising a semiconductor channel layer having an electrically conducting channel; an ohmic contact layer on the semiconductor channel layer, the ohmic contact layer having a recess structure disposed therethrough to the semiconductor channel layer; the bottom of the ohmic contact layer comprising an etch stop layer comprising Aluminium and Phosphorous and defining the shape of the recess at its junction with the semiconductor channel layer.
    Type: Application
    Filed: April 30, 2009
    Publication date: October 22, 2009
    Applicant: FILTRONIC PLC
    Inventors: Matthew Francis O'Keefe, Michael Charles Clausen, Richard Alun Davies, Robert Grey
  • Patent number: 7538365
    Abstract: A III-V field effect transistor includes a semiconductor channel layer having an electrically conducting channel and an ohmic contact layer on the semiconductor channel layer. The ohmic contact layer has a recess structure disposed therethrough to the semiconductor channel layer. The bottom of the ohmic contact layer includes an etch stop layer including Aluminum and Phosphorous and defining the shape of the recess at its junction with the semiconductor channel layer.
    Type: Grant
    Filed: June 15, 2005
    Date of Patent: May 26, 2009
    Assignee: Filtronic PLC
    Inventors: Matthew Francis O'Keefe, Michael Charles Clausen, Richard Alun Davies, Robert Grey
  • Publication number: 20080237643
    Abstract: A heterojunction bipolar transistor comprising a substrate; a collector on the substrate; a base layer on the collector; an emitter layer on the base layer; the emitter layer comprising an upper emitter layer and a lower emitter layer between the upper emitter layer and base; the collector, base and emitter layers being npn or pnp doped respectively; characterised in that the lower emitter layer has a larger bandgap than the base layer and is AlxIn1-xP or GaxAl1-xP, x being in the range 0+ to 1.
    Type: Application
    Filed: March 27, 2008
    Publication date: October 2, 2008
    Applicant: FITRONIC COMPOUND SEMICONDUCTORS LIMITED
    Inventors: Matthew Francis O'Keefe, Robert Grey, Michael Charles Clausen, Richard Alun Davies
  • Publication number: 20080153303
    Abstract: A III-V field effect transistor comprising a semiconductor channel layer having an electrically conducting channel; an ohmic contact layer on the semiconductor channel layer, the ohmic contact layer having a recess structure disposed therethrough to the semiconductor channel layer; the bottom of the ohmic contact layer comprising an etch stop layer comprising Aluminium and Phosphorous and defining the shape of the recess at its junction with the semiconductor channel layer.
    Type: Application
    Filed: March 7, 2008
    Publication date: June 26, 2008
    Applicant: FILTRONIC PLC
    Inventors: Matthew Francis O'Keefe, Michael Charles Clausen, Richard Alun Davies, Robert Grey
  • Publication number: 20070241429
    Abstract: An electrically conducting track comprising an electrically conducting track layer; a semiconductor substrate; and a dielectric layer sandwiched between track layer and semiconductor substrate; the electrically conducting track further comprising an electrically conducting resistor track between semiconductor substrate and dielectric layer
    Type: Application
    Filed: April 18, 2007
    Publication date: October 18, 2007
    Applicant: FILTRONIC COMPOUND SEMICONDUCTORS LIMITED
    Inventors: Ron Arnold, John Stephen Atherton, Nigel Cameron, Matthew Francis O'Keefe
  • Patent number: 6846698
    Abstract: A method of handling a semiconductor wafer from which a plurality of semiconductor devices are to be fabricated during a semiconductor device fabrication process. The method includes the steps of attaching a flexible connected layer to a semiconductor wafer layer mounted on a carrier substrate and separating the wafer layer from the carrier substrate while supported by the flexible connected layer.
    Type: Grant
    Filed: April 19, 2002
    Date of Patent: January 25, 2005
    Assignee: Filtronic Compound Semiconductor Ltd.
    Inventors: Matthew Francis O'Keefe, John Melvyn Cullen
  • Publication number: 20020177257
    Abstract: A method of handling a semiconductor wafer from which a plurality of semiconductor devices are to be fabricated during a semiconductor device fabrication process. The method includes the steps of attaching a flexible connected layer to a semiconductor wafer layer mounted on a carrier substrate and separating the wafer layer from the carrier substrate while supported by the flexible connected layer.
    Type: Application
    Filed: April 19, 2002
    Publication date: November 28, 2002
    Applicant: Filtronic Compound Semiconductor Limited
    Inventors: Matthew Francis O'Keefe, John Melvyn Cullen
  • Patent number: 5939739
    Abstract: The present invention relates to a heterojunction bipolar transistor structure having a device mesa 401 with a collector region 402, a base region 403 and an emitter region 404. An emitter metal layer 405 is connected to a ballast resistor 406 which in turn is connected to an emitter bump 407 by way of the air bridge 408. The thermal bump 409 is connected to the emitter metallization by way of a layer of heat dissipation material 410, preferably silicon nitride. The present structure enables dissipation of heat at the emitter contact as well as a ballast resistor connected to the emitter by way of metallization 405. This arrangement enables the dissipation of joule heat to avoid higher temperature of operation which results increased current at the collector which increases the temperature thereby further increasing the current, as well as provides a ballast resistor to reduce the collector current back to an acceptable value to avoid thermal runaway.
    Type: Grant
    Filed: May 30, 1997
    Date of Patent: August 17, 1999
    Assignee: The Whitaker Corporation
    Inventor: Matthew Francis O'Keefe