Patents by Inventor Andy Strachan

Andy Strachan 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: 9865584
    Abstract: A contact array optimization scheme for ESD devices. In one embodiment, contact apertures patterned through a pre-metal dielectric layer over active areas may be selectively modified in size, shape, placement and the like, to increase ESD protection performance, e.g., such as maximizing the transient current density, etc., in a standard ESD rating test.
    Type: Grant
    Filed: November 4, 2016
    Date of Patent: January 9, 2018
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventors: He Lin, Kun Chen, Chao Wu, Dening Wang, Lily Springer, Andy Strachan, Gang Xue
  • Publication number: 20180006013
    Abstract: A contact array optimization scheme for ESD devices. In one embodiment, contact apertures patterned through a pre-metal dielectric layer over active areas may be selectively modified in size, shape, placement and the like, to increase ESD protection performance, e.g., such as maximizing the transient current density, etc., in a standard ESD rating test.
    Type: Application
    Filed: November 4, 2016
    Publication date: January 4, 2018
    Inventors: He LIN, Kun CHEN, Chao WU, Dening WANG, Lily SPRINGER, Andy STRACHAN, Gang XUE
  • Patent number: 7989883
    Abstract: A system and method is disclosed that prevents the formation of a vertical bird's beak structure in the manufacture of a semiconductor device. A polysilicon filled trench is formed in a substrate of the semiconductor device. One or more composite layers are then applied over the trench and the substrate. A mask and etch process is then applied to etch the composite layers adjacent to the polysilicon filled trench. A field oxide process is applied to form field oxide portions in the substrate adjacent to the trench. Because no field oxide is placed over the trench there is no formation of a vertical bird's beak structure. A gate oxide layer is applied and a protection cap is formed over the polysilicon filled trench to protect the trench from unwanted effects of subsequent processing steps.
    Type: Grant
    Filed: January 16, 2009
    Date of Patent: August 2, 2011
    Assignee: National Semiconductor Corporation
    Inventors: Charles A. Dark, Andy Strachan
  • Patent number: 7960998
    Abstract: A test structure and testing method are provided for characterizing the time-dependent drift in the parasitic PFET leakage current that flows along the sidewall of a deep trench isolation structure from the P-type active area to the P-type substrate in a semiconductor integrated circuit structure. The capacitive coupling characteristics of the deep trench isolation structure are used to control the electrical “bias” of the deep trench structure through the use of a large auxiliary trench mesh network that is formed as part of the deep trench structure. The trench mesh network can be placed adjacent to a Vdd ring or a ground ring and then, by using a ratioed capacitive voltage dividing network, the electrical potential at the trench can be controlled.
    Type: Grant
    Filed: September 17, 2008
    Date of Patent: June 14, 2011
    Assignee: National Semiconductor Corporation
    Inventors: Lisa V. Rozario, Andy Strachan, Richard Orr
  • Publication number: 20110065256
    Abstract: An efficient method is disclosed for increasing the breakdown voltage of an integrated circuit device that is isolated by a local oxidation of silicon (LOCOS) process. The method comprises forming a portion of a field oxide in an integrated circuit so that the field oxide has a gradual profile. The gradual profile of the field oxide reduces impact ionization in the field oxide by creating a reduced value of electric field for a given value of applied voltage. The reduction in impact ionization increases the breakdown voltage of the integrated circuit. The gradual profile is formed by using an increased thickness of pad oxide and a reduced thickness of silicon nitride during a field oxide oxidation process.
    Type: Application
    Filed: November 29, 2010
    Publication date: March 17, 2011
    Applicant: National Semiconductor Corporation
    Inventors: Richard W. Foote, JR., Terry Lee Lines, Alexei Sadovnikov, Andy Strachan
  • Patent number: 7867871
    Abstract: An efficient method is disclosed for increasing the breakdown voltage of an integrated circuit device that is isolated by a local oxidation of silicon (LOCOS) process. The method comprises forming a portion of a field oxide in an integrated circuit so that the field oxide has a gradual profile. The gradual profile of the field oxide reduces impact ionization in the field oxide by creating a reduced value of electric field for a given value of applied voltage. The reduction in impact ionization increases the breakdown voltage of the integrated circuit. The gradual profile is formed by using an increased thickness of pad oxide and a reduced thickness of silicon nitride during a field oxide oxidation process.
    Type: Grant
    Filed: July 13, 2006
    Date of Patent: January 11, 2011
    Assignee: National Semiconductor Corporation
    Inventors: Richard W. Foote, Terry Lee Lines, Alexei Sadovnikov, Andy Strachan
  • Patent number: 7714355
    Abstract: In a BSCR or BJT ESD clamp, the breakdown voltage and DC voltage tolerance are controlled by controlling the size of the collector of the BJT device by masking part of the collector.
    Type: Grant
    Filed: December 20, 2005
    Date of Patent: May 11, 2010
    Assignee: National Semiconductor Corp
    Inventors: Vladislav Vashchenko, Alexei Sadovnikov, Peter J. Hopper, Andy Strachan
  • Publication number: 20090206865
    Abstract: A test structure and testing method are provided for characterizing the time-dependent drift in the parasitic PFET leakage current that flows along the sidewall of a deep trench isolation structure from the P-type active area to the P-type substrate in a semiconductor integrated circuit structure. The capacitive coupling characteristics of the deep trench isolation structure are used to control the electrical “bias” of the deep trench structure through the use of a large auxiliary trench mesh network that is formed as part of the deep trench structure. The trench mesh network can be placed adjacent to a Vdd ring or a ground ring and then, by using a ratioed capacitive voltage dividing network, the electrical potential at the trench can be controlled.
    Type: Application
    Filed: September 17, 2008
    Publication date: August 20, 2009
    Inventors: Lisa V. Rozario, Andy Strachan, Richard Orr
  • Patent number: 7507607
    Abstract: A silicide bridged anti-fuse and a method of forming the anti-fuse are disclosed. The silicide bridged anti-fuse can be formed with a tungsten plug metalization process that does not require any additional process steps. As a result, anti-fuses can be added to an electrical circuit as trim elements for no additional cost.
    Type: Grant
    Filed: June 29, 2004
    Date of Patent: March 24, 2009
    Assignee: National Semiconductor Corporation
    Inventors: Charles A. Dark, William M. Coppock, Jeffery L. Nilles, Andy Strachan
  • Patent number: 7488647
    Abstract: A system and method is disclosed that prevents the formation of a vertical bird's beak structure in the manufacture of a semiconductor device. A polysilicon filled trench is formed in a substrate of the semiconductor device. One or more composite layers are then applied over the trench and the substrate. A mask and etch process is then applied to etch the composite layers adjacent to the polysilicon filled trench. A field oxide process is applied to form field oxide portions in the substrate adjacent to the trench. Because no field oxide is placed over the trench there is no formation of a vertical bird's beak structure. A gate oxide layer is applied and a protection cap is formed over the polysilicon filled trench to protect the trench from unwanted effects of subsequent processing steps.
    Type: Grant
    Filed: August 11, 2005
    Date of Patent: February 10, 2009
    Assignee: National Semiconductor Corporation
    Inventors: Charles A. Dark, Andy Strachan
  • Patent number: 7479435
    Abstract: A MOS transistor and subsurface collectors can be formed by using a hard mask and precisely varying the implant angle, rotation, dose, and energy. In this case, a particular atomic species can be placed volumetrically in a required location under the hard mask. The dopant can be implanted to form sub-silicon volumes of arbitrary shapes, such as pipes, volumes, hemispheres, and interconnects.
    Type: Grant
    Filed: December 8, 2004
    Date of Patent: January 20, 2009
    Assignee: National Semiconductor Corporation
    Inventors: Peter J. Hopper, Vladislav Vashchenko, Philipp Lindorfer, Andy Strachan
  • Patent number: 7298159
    Abstract: The trench leakage current of a deep trench isolation structure is measured. The deep trench isolation structure, which is filled with polysilicon, contacts both a first region of a first conductivity type and a second region of a second conductivity type, and is proximate to a third region of the first conductivity type formed in the second region. Test voltages are applied to the structures and the leakage current is measured.
    Type: Grant
    Filed: July 7, 2005
    Date of Patent: November 20, 2007
    Assignee: National Semiconductor Corporation
    Inventors: Lisa V. Rozario, Andy Strachan
  • Patent number: 7238553
    Abstract: When a high-voltage, such as from an ESD pulse, is placed across a silicon controlled rectifier, which includes an NPN transistor and a PNP transistor that is connected to the NPN transistor, the likelihood of punch through occurring between two regions of the rectifier is substantially reduced by forming the emitter of one transistor adjacent to the tails of the sinker down region of the other transistor.
    Type: Grant
    Filed: May 23, 2005
    Date of Patent: July 3, 2007
    Assignee: National Semiconductor Corporation
    Inventors: Vladislav Vashchenko, Andy Strachan, Peter J. Hopper, Philipp Lindorfer
  • Patent number: 7214992
    Abstract: The drain breakdown voltage walk-in of a dual-source, dual-gate PMOS transistor is significantly reduced by utilizing source regions which have a width that is equal to or less than a width of the drain region. By utilizing source regions with widths that are equal to or less than the width of the drain region, the current density in the drain region is significantly reduced which reduces the number of hot charge carriers that are trapped at the silicon-to-silicon dioxide interface which, turn in, reduces the drain breakdown voltage walk-in rate.
    Type: Grant
    Filed: October 27, 2004
    Date of Patent: May 8, 2007
    Assignee: National Semiconductor Corporation
    Inventors: Andy Strachan, Douglas Brisbin
  • Patent number: 7192857
    Abstract: A power transistor structure uses metal drain and source strips with non-uniform widths to reduce variations in current density across the power transistor structure. The reductions in current density, in turn, reduce the source-to-drain turn on resistance and maximize the overall current carrying capacity of power transistor structure.
    Type: Grant
    Filed: April 20, 2005
    Date of Patent: March 20, 2007
    Assignee: National Semiconductor Corporation
    Inventors: Peter J. Hopper, Philipp Lindorfer, Vladislav Vashchenko, Andy Strachan
  • Patent number: 7105373
    Abstract: A single junction interdigitated photodiode utilizes a stack of alternating highly doped first regions of a first conductivity type and highly doped second regions of a second conductivity type, which are formed below and contact the first regions, to collect photons. In addition, a highly doped sinker of a first conductivity type contacts each first region, and a highly doped sinker of a second conductivity type contacts each second region.
    Type: Grant
    Filed: August 14, 2003
    Date of Patent: September 12, 2006
    Assignee: National Semiconductor Corporation
    Inventors: Peter J. Hopper, Philipp Lindorfer, Vladislav Vashchenko, Andy Strachan
  • Patent number: 7037814
    Abstract: In an integrated circuit, dopant concentration levels are adjusted by making use of a perforated mask. Doping levels for different regions across an integrated circuit can be differently defined by making use of varying size and spacings to the perforations in the mask. The diffusion of dopant is completed by making use of an annealing stage.
    Type: Grant
    Filed: October 10, 2003
    Date of Patent: May 2, 2006
    Assignee: National Semiconductor Corporation
    Inventors: Vladislav Vashchenko, Andy Strachan, Peter J. Hopper, Philipp Lindorfer
  • Patent number: 6979879
    Abstract: In a zener zap diode device and a system for making such a device using a double poly process, p+ and n+regions are formed in a tub by means of p-doped and n-doped polysilicon regions, and a p-n junction is formed between the p+ region and an n-tub or between the n+ region and a p-tub. Cobalt or other refractory metal is reacted with silicon to form a silicide on at least the p-doped polysilicon region. By reverse biasing the p-n junction and establishing a sufficiently high zap current, the silicide can be forced to migrate across the junction to form a silicide bridge thereby selectively shorting out the p-n junction.
    Type: Grant
    Filed: April 30, 2004
    Date of Patent: December 27, 2005
    Assignee: National Semiconductor Corporation
    Inventors: Wipawan Yindeepol, Andy Strachan
  • Patent number: 6946706
    Abstract: An LDMOS structure which provides for reduced hot carrier effects. The reduction in hot carrier effects is achieved by increasing the size of the drain region of the LDMOS relative to the size of the source region. The larger size of the drain region reduces the concentration of electrons entering the drain region. This reduction in the concentration of electrons reduces the number of impact ionizations, which in turn reduces the hot carrier effects. The overall performance of the LDMOS is improved by reducing the hot carrier effects.
    Type: Grant
    Filed: July 9, 2003
    Date of Patent: September 20, 2005
    Assignee: National Semiconductor Corporation
    Inventors: Douglas Brisbin, David Tsuei, Alexander H. Owens, Andy Strachan
  • Patent number: 6933562
    Abstract: A power transistor structure uses metal drain and source strips with non-uniform widths to reduce variations in current density across the power transistor structure. The reductions in current density, in turn, reduce the source-to-drain turn on resistance and maximize the overall current carrying capacity of power transistor structure.
    Type: Grant
    Filed: June 27, 2003
    Date of Patent: August 23, 2005
    Assignee: National Semiconductor Corporation
    Inventors: Peter J. Hopper, Philipp Lindorfer, Vladislav Vashchenko, Andy Strachan