Patents by Inventor Michael Charles Clausen

Michael Charles Clausen 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).

  • Transistor
    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
  • Compound semiconductor substrate for a field effect transistor
    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
  • Compound Semiconductor Substrate For a Field Effect Transistor
    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
  • Field effect transistor with aluminum and phosphorus etch stop layer
    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
  • TRANSISTOR
    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
  • FIELD EFFECT TRANSISTOR, COMPOUND SEMICONDUCTOR SUBSTRATE AND PROCESS FOR FORMING A RECESS THEREIN
    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