Patents Assigned to Cambridge Semiconductor Limited
  • Publication number: 20070158678
    Abstract: A high voltage/power semiconductor device has a relatively lowly doped substrate, an insulating layer on the substrate, and a semiconductor layer on the insulating layer. A low voltage terminal and a high voltage terminal are each electrically connected to the semiconductor layer. The device has a control terminal. The semiconductor layer includes a drift region of a first conductivity type, the substrate being of the second conductivity type. The semiconductor layer includes a relatively highly doped injector region of the second conductivity type between the drift region and the high voltage terminal, said relatively highly doped injector region being in electrical contact with the high voltage terminal and not being connected via any semiconductor layer to the substrate. The device has a relatively highly doped region of the first conductivity type in electrical contact with the said highly doped injector region and the high voltage terminal and forming a semiconductor junction with the substrate.
    Type: Application
    Filed: December 30, 2005
    Publication date: July 12, 2007
    Applicant: CAMBRIDGE SEMICONDUCTOR LIMITED
    Inventor: Florin Udrea
  • Patent number: 7235439
    Abstract: A power semiconductor device has an active region that includes a drift region. At least a portion of the drift region is provided in a membrane which has opposed top and bottom surfaces. In one embodiment, the top surface of the membrane has electrical terminals connected directly or indirectly thereto to allow a voltage to be applied laterally across the drift region. In another embodiment, at least one electrical terminal is connected directly or indirectly to the top surface and at least one electrical terminal is connected directly or indirectly to the bottom surface to allow a voltage to be applied vertically across the drift region. In each of these embodiments, the bottom surface of the membrane does not have a semiconductor substrate positioned adjacent thereto.
    Type: Grant
    Filed: July 6, 2005
    Date of Patent: June 26, 2007
    Assignee: Cambridge Semiconductor Limited
    Inventors: Florin Udrea, Gehan A J Amaratunga
  • Patent number: 7230314
    Abstract: A semiconductor device having an active region is formed in a layer provided on a semiconductor substrate. At least a portion of the semiconductor substrate below at least a portion of the active region is removed such that the portion of the active region is provided in a membrane defined by that portion of the layer below which the semiconductor substrate has been removed. A heat conducting and electrically insulating layer is applied to the bottom surface of the membrane. The heat conducting and electrically insulating layer has a thermal conductivity that is higher than the thermal conductivity of the membrane so that the heat conducting and electrically insulating layer allows heat to pass from the active region into the heat conducting and electrically insulating layer during normal operation of the device.
    Type: Grant
    Filed: March 28, 2003
    Date of Patent: June 12, 2007
    Assignee: Cambridge Semiconductor Limited
    Inventors: Florin Udrea, Gehan A. J. Amaratunga
  • Publication number: 20070120187
    Abstract: This invention is generally concerned with semiconductor-on-insulator devices, particularly for high voltage applications. A lateral semiconductor-on-insulator device is described, comprising: a semiconductor substrate; an insulating layer on said semiconductor substrate; and a lateral semiconductor device on said insulator; said lateral semiconductor device having: a first region of a first conductivity type; a second region of a second conductivity type laterally spaced apart from said first region; and a drift region extending in a lateral direction between said first region and said second region; and wherein said drift region comprises at least one first zone and at least one second zone adjacent a said first zone, a said first zone having said second conductivity type, a said second zone being an insulating zone, a said first zone being tapered to narrow towards said first region.
    Type: Application
    Filed: May 13, 2003
    Publication date: May 31, 2007
    Applicant: CAMBRIDGE SEMICONDUCTOR LIMITED
    Inventors: Florin Udrea, David Garner
  • Publication number: 20060261443
    Abstract: A bipolar high voltage/power semiconductor device has a low voltage terminal and a high voltage terminal. The device has a drift region of a first conductivity type and having first and second ends. In one example, a region of the second conductivity type is provided at the second end of the drift region connected directly to the high voltage terminal. In another example, a buffer region of the first conductivity type is provided at the second end of the drift region and a region of a second conductivity type is provided on the other side of the buffer region and connected to the high voltage terminal. Plural electrically floating island regions are provided within the drift region at or towards the second end of the drift region, the plural electrically floating island regions being of the first conductivity type and being more highly doped than the drift region.
    Type: Application
    Filed: May 20, 2005
    Publication date: November 23, 2006
    Applicant: Cambridge Semiconductor Limited
    Inventor: Florin Udrea
  • Publication number: 20060067137
    Abstract: A high voltage/power semiconductor device has at least one active region having a plurality of high voltage junctions electrically connected in parallel. At least part of each of the high voltage junctions is located in or on a respective membrane such that the active region is provided at least in part over plural membranes. There are non-membrane regions between the membranes. The device has a low voltage terminal and a high voltage terminal. At least a portion of the low voltage terminal and at least a portion of the high voltage terminal are connected directly or indirectly to a respective one of the high voltage junctions. At least those portions of the high voltage terminal that are in direct or indirect contact with one of the high voltage junctions are located on or in a respective one of the plural membranes.
    Type: Application
    Filed: September 1, 2005
    Publication date: March 30, 2006
    Applicant: CAMBRIDGE SEMICONDUCTOR LIMITED
    Inventors: Florin Udrea, Gehan Amaratunga
  • Publication number: 20050242369
    Abstract: A power semiconductor device has an active region that includes a drift region. At least a portion of the drift region is provided in a membrane which has opposed top and bottom surfaces. In one embodiment, the top surface of the membrane has electrical terminals connected directly or indirectly thereto to allow a voltage to be applied laterally across the drift region. In another embodiment, at least one electrical terminal is connected directly or indirectly to the top surface and at least one electrical terminal is connected directly or indirectly to the bottom surface to allow a voltage to be applied vertically across the drift region. In each of these embodiments, the bottom surface of the membrane does not have a semiconductor substrate positioned adjacent thereto.
    Type: Application
    Filed: July 6, 2005
    Publication date: November 3, 2005
    Applicant: CAMBRIDGE SEMICONDUCTOR LIMITED
    Inventors: Florin Udrea, Gehan Amaratunga
  • Publication number: 20050242368
    Abstract: A power semiconductor device has an active region that includes a drift region. At least a portion of the drift region is provided in a membrane which has opposed top and bottom surfaces. In one embodiment, the top surface of the membrane has electrical terminals connected directly or indirectly thereto to allow a voltage to be applied laterally across the drift region. In another embodiment, at least one electrical terminal is connected directly or indirectly to the top surface and at least one electrical terminal is connected directly or indirectly to the bottom surface to allow a voltage to be applied vertically across the drift region. In each of these embodiments, the bottom surface of the membrane does not have a semiconductor substrate positioned adjacent thereto.
    Type: Application
    Filed: July 6, 2005
    Publication date: November 3, 2005
    Applicant: CAMBRIDGE SEMICONDUCTOR LIMITED
    Inventors: Florin Udrea, Gehan Amaratunga
  • Patent number: 6927102
    Abstract: A power semiconductor device has an active region that includes a drift region. At least a portion of the drift region is provided in a membrane which has opposed top and bottom surfaces. In one embodiment, the top surface of the membrane has electrical terminals connected directly or indirectly thereto to allow a voltage to be applied laterally across the drift region. In another embodiment, at least one electrical terminal is connected directly or indirectly to the top surface and at least one electrical terminal is connected directly or indirectly to the bottom surface to allow a voltage to be applied vertically across the drift region. In each of these embodiments, the bottom surface of the membrane does not have a semiconductor substrate positioned adjacent thereto.
    Type: Grant
    Filed: October 29, 2003
    Date of Patent: August 9, 2005
    Assignee: Cambridge Semiconductor Limited
    Inventors: Florin Udrea, Gehan A. J. Amaratunga
  • Patent number: 6900518
    Abstract: A power semiconductor device has an active region that includes a drift region. At least a portion of the drift region is provided in a membrane which has opposed top and bottom surfaces. In one embodiment, the top surface of the membrane has electrical terminals connected directly or indirectly thereto to allow a voltage to be applied laterally across the drift region. In another embodiment, at least one electrical terminal is connected directly or indirectly to the top surface and at least one electrical terminal is connected directly or indirectly to the bottom surface to allow a voltage to be applied vertically across the drift region. In each of these embodiments, the bottom surface of the membrane does not have a semiconductor substrate positioned adjacent thereto.
    Type: Grant
    Filed: October 29, 2003
    Date of Patent: May 31, 2005
    Assignee: Cambridge Semiconductor Limited
    Inventors: Florin Udrea, Gehan A. J. Amaratunga
  • Patent number: 6858884
    Abstract: A lateral semiconductor device (10) has a semiconductor layer (15) on an insulating substrate (16). The semiconductor layer (15) has a first region (12) of a first conduction type and a second region (13) of a second conduction type with a drift region (14) therebetween. The drift region (14) is provided by a third region (14?) of the first conduction type and a fourth region (14?) of the second conduction type. The third and fourth (drift) regions (14?,14?) are so arranged that when a reverse voltage bias is applied across the first and second regions (12,13) of the semiconductor layer (15), the third region (14?) has locally in the proximity of the first region (12) an excess of impurity charge relative to the fourth region (14?), and the fourth region (14?) has locally in the proximity of the second region (13) an excess of impurity charge relative to the third region (14?), and the total volume charge in the third region (14?) is substantially equal to the total volume charge in the fourth region (14?).
    Type: Grant
    Filed: June 24, 2003
    Date of Patent: February 22, 2005
    Assignee: Cambridge Semiconductor Limited
    Inventor: Florin Udrea
  • Publication number: 20040087065
    Abstract: A power semiconductor device has an active region that includes a drift region. At least a portion of the drift region is provided in a membrane which has opposed top and bottom surfaces. In one embodiment, the top surface of the membrane has electrical terminals connected directly or indirectly thereto to allow a voltage to be applied laterally across the drift region. In another embodiment, at least one electrical terminal is connected directly or indirectly to the top surface and at least one electrical terminal is connected directly or indirectly to the bottom surface to allow a voltage to be applied vertically across the drift region. In each of these embodiments, the bottom surface of the membrane does not have a semiconductor substrate positioned adjacent thereto.
    Type: Application
    Filed: October 29, 2003
    Publication date: May 6, 2004
    Applicant: CAMBRIDGE SEMICONDUCTOR LIMITED
    Inventors: Florin Udrea, Gehan A.J. Amaratunga
  • Publication number: 20040084752
    Abstract: A power semiconductor device has an active region that includes a drift region. At least a portion of the drift region is provided in a membrane which has opposed top and bottom surfaces. In one embodiment, the top surface of the membrane has electrical terminals connected directly or indirectly thereto to allow a voltage to be applied laterally across the drift region. In another embodiment, at least one electrical terminal is connected directly or indirectly to the top surface and at least one electrical terminal is connected directly or indirectly to the bottom surface to allow a voltage to be applied vertically across the drift region. In each of these embodiments, the bottom surface of the membrane does not have a semiconductor substrate positioned adjacent thereto.
    Type: Application
    Filed: October 29, 2003
    Publication date: May 6, 2004
    Applicant: CAMBRIDGE SEMICONDUCTOR LIMITED
    Inventors: Florin Udrea, Gehan A.J. Amaratunga
  • Publication number: 20040051141
    Abstract: A lateral semiconductor device (10) has a semiconductor layer (15) on an insulating substrate (16). The semiconductor layer (15) has a first region (12) of a first conduction type and a second region (13) of a second conduction type with a drift region (14) therebetween. The drift region (14) is provided by a third region (14″) of the first conduction type and a fourth region (14′) of the second conduction type.
    Type: Application
    Filed: June 24, 2003
    Publication date: March 18, 2004
    Applicant: CAMBRIDGE SEMICONDUCTOR LIMITED
    Inventor: Florin Udrea
  • Patent number: 6703684
    Abstract: A power semiconductor device (10) has an active region that includes a drift region (20). At least a portion of the drift region (20) is provided in a membrane (16) which has opposed top and bottom surfaces (15,17). In one embodiment, the top surface (15) of the membrane (16) has electrical terminals connected directly or indirectly thereto to allow a voltage to be applied laterally across the drift region (20). In another embodiment, at least one electrical terminal is connected directly or indirectly to the top surface (15) and at least one electrical terminal is connected directly or indirectly to the bottom surface (17) to allow a voltage to be applied vertically across the drift region (20). In each of these embodiments, the bottom surface (17) of the membrane (16) does not have a semiconductor substrate positioned adjacent thereto.
    Type: Grant
    Filed: September 21, 2001
    Date of Patent: March 9, 2004
    Assignee: Cambridge Semiconductor Limited
    Inventors: Florin Udrea, Gehan A. J. Amaratunga
  • Publication number: 20030183923
    Abstract: A semiconductor device having an active region is formed in a layer provided on a semiconductor substrate. At least a portion of the semiconductor substrate below at least a portion of the active region is removed such that the portion of the active region is provided in a membrane defined by that portion of the layer below which the semiconductor substrate has been removed. A heat conducting and electrically insulating layer is applied to the bottom surface of the membrane. The heat conducting and electrically insulating layer has a thermal conductivity that is higher than the thermal conductivity of the membrane so that the heat conducting and electrically insulating layer allows heat to pass from the active region into the heat conducting and electrically insulating layer during normal operation of the device.
    Type: Application
    Filed: March 28, 2003
    Publication date: October 2, 2003
    Applicant: CAMBRIDGE SEMICONDUCTOR LIMITED
    Inventors: Florin Udrea, Gehan A.J. Amaratunga
  • Patent number: 6566240
    Abstract: A semiconductor device having an active region is formed in a layer provided on a semiconductor substrate. At least a portion of the semiconductor substrate below at least a portion of the active region is removed such that the portion of the active region is provided in a membrane defined by that portion of the layer below which the semiconductor substrate has been removed. A heat conducting and electrically insulating layer is applied to the bottom surface of the membrane. The heat conducting and electrically insulating layer has a thermal conductivity that is higher than the thermal conductivity of the membrane so that the heat conducting and electrically insulating layer allows heat to pass from the active region into the heat conducting and electrically insulating layer during normal operation of the device.
    Type: Grant
    Filed: September 21, 2001
    Date of Patent: May 20, 2003
    Assignee: Cambridge Semiconductor Limited
    Inventors: Florin Udrea, Gehan A. J. Amaratunga
  • Publication number: 20020041003
    Abstract: A power semiconductor device (10) has an active region that includes a drift region (20). At least a portion of the drift region (20) is provided in a membrane (16) which has opposed top and bottom surfaces (15, 17). In one embodiment, the top surface (15) of the membrane (16) has electrical terminals connected directly or indirectly thereto to allow a voltage to be applied laterally across the drift region (20). In another embodiment, at least one electrical terminal is connected directly or indirectly to the top surface (15) and at least one electrical terminal is connected directly or indirectly to the bottom surface (17) to allow a voltage to be applied vertically across the drift region (20). In each of these embodiments, the bottom surface (17) of the membrane (16) does not have a semiconductor substrate positioned adjacent thereto.
    Type: Application
    Filed: September 21, 2001
    Publication date: April 11, 2002
    Applicant: CAMBRIDGE SEMICONDUCTOR LIMITED
    Inventors: Florin Udrea, Gehan Amaratunga
  • Publication number: 20020034843
    Abstract: A semiconductor device (10) having an active region is formed in a layer (11) provided on a semiconductor substrate (13). At least a portion (13′) of the semiconductor substrate (13) below at least a portion of the active region is removed such that the portion of the active region is provided in a membrane (14) defined by that portion of the layer (11) below which the semiconductor substrate (13) has been removed. A heat conducting and electrically insulating layer (20) is applied to the bottom surface (16) of the membrane (14). The heat conducting and electrically insulating layer (20) has a thermal conductivity that is higher than the thermal conductivity of the membrane (14) so that the heat conducting and electrically insulating layer (20) allows heat to pass from the active region into the heat conducting and electrically insulating layer (20) during normal operation of the device (10).
    Type: Application
    Filed: September 21, 2001
    Publication date: March 21, 2002
    Applicant: CAMBRIDGE SEMICONDUCTOR LIMITED
    Inventors: Florin Udrea, Gehan A.J. Amaratunga