Patents by Inventor Daniel S. Calafut

Daniel S. Calafut 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: 7768034
    Abstract: An electrostatic discharge (ESD) protection network for power MOSFETs includes parallel branches, containing polysilicon zener diodes and resistors, used for protecting the gate from rupture caused by high voltages caused by ESD. The branches may have the same or independent paths for voltage to travel across from the gate region into the semiconductor substrate. Specifically, the secondary branch has a higher breakdown voltage than the primary branch so that the voltage is shared across the two branches of the protection network. The ESD protection network of the device provides a more effective design without increasing the space used on the die. The ESD protection network can also be used with other active and passive devices such as thyristors, insulated-gate bipolar transistors, and bipolar junction transistors.
    Type: Grant
    Filed: October 1, 2007
    Date of Patent: August 3, 2010
    Assignee: Fairchild Semiconductor Corporation
    Inventors: Daniel S. Calafut, Hamza Yilmaz, Steven Sapp
  • Patent number: 7625793
    Abstract: A double-diffused metal-oxide-semiconductor (“DMOS”) field-effect transistor with an improved gate structure. The gate structure includes a first portion of a first conductivity type for creating electron flow from the source to the drain when a charge is applied to the gate. The gate structure includes a second portion of a second conductivity type having a polarity that is opposite a polarity of the first conductivity type, for decreasing a capacitance charge under the gate. A second structure for decreasing a capacitance under the gate includes an implant region in the semiconductor substrate between a channel region, where the implant region is doped to have a conductivity opposite the channel region.
    Type: Grant
    Filed: September 26, 2005
    Date of Patent: December 1, 2009
    Assignee: Fairchild Semiconductor Corporation
    Inventor: Daniel S. Calafut
  • Publication number: 20040232407
    Abstract: A double-diffused metal-oxide-semiconductor (“DMOS”) field-effect transistor with an improved gate structure. The gate structure includes a first portion of a first conductivity type for creating electron flow from the source to the drain when a charge is applied to the gate. The gate structure includes a second portion of a second conductivity type having a polarity that is opposite a polarity of the first conductivity type, for decreasing a capacitance charge under the gate. A second structure for decreasing a capacitance under the gate includes an implant region in the semiconductor substrate between a channel region, where the implant region is doped to have a conductivity opposite the channel region.
    Type: Application
    Filed: March 17, 2003
    Publication date: November 25, 2004
    Applicant: Fairchild Semiconductor Corporation
    Inventor: Daniel S. Calafut
  • Patent number: 6673680
    Abstract: A power metal oxide semiconductor-field-effect-transistor (MOSFET) device using trench technology to achieve a reduced-mask-production process. The power MOSFET device includes a gate signal bus having multiple gate trenches formed using fewer masks than previously required for a similar device. The two-dimensional behavior of the trenches provides an advantageous field-coupling effect that suppresses hot-carrier generation without the need for the commonly used thick layer of silicon dioxide beneath the gate polysilicon. The use of easily controlled silicon trench etching in production of the power MOSFET results in stable, low cost, and high yielding manufacturing.
    Type: Grant
    Filed: March 25, 2002
    Date of Patent: January 6, 2004
    Assignee: Fairchild Semiconductor Corporation
    Inventor: Daniel S. Calafut
  • Patent number: 6534825
    Abstract: A double-diffused metal-oxide-semiconductor (“DMOS”) field-effect transistor with an improved gate structure. The gate structure includes a first portion of a first conductivity type for creating electron flow from the source to the drain when a charge is applied to the gate. The gate structure includes a second portion of a second conductivity type having a polarity that is opposite a polarity of the first conductivity type, for decreasing a capacitance charge under the gate. A second structure for decreasing a capacitance under the gate includes an implant region in the semiconductor substrate between a channel region, where the implant region is doped to have a conductivity opposite the channel region.
    Type: Grant
    Filed: August 14, 2002
    Date of Patent: March 18, 2003
    Assignee: Fairchild Semiconductor Corporation
    Inventor: Daniel S. Calafut
  • Publication number: 20020190282
    Abstract: A double-diffused metal-oxide-semiconductor (“DMOS”) field-effect transistor with an improved gate structure. The gate structure includes a first portion of a first conductivity type for creating electron flow from the source to the drain when a charge is applied to the gate. The gate structure includes a second portion of a second conductivity type having a polarity that is opposite a polarity of the first conductivity type, for decreasing a capacitance charge under the gate. A second structure for decreasing a capacitance under the gate includes an implant region in the semiconductor substrate between a channel region, where the implant region is doped to have a conductivity opposite the channel region.
    Type: Application
    Filed: August 14, 2002
    Publication date: December 19, 2002
    Applicant: Fairchild Semiconductor Corporation
    Inventor: Daniel S. Calafut
  • Patent number: 6461918
    Abstract: A double-diffused metal-oxide-semiconductor (“DMOS”) field-effect transistor with an improved gate structure. The gate structure includes a first portion of a first conductivity type for creating electron flow from the source to the drain when a charge is applied to the gate. The gate structure includes a second portion of a second conductivity type having a polarity that is opposite a polarity of the first conductivity type, for decreasing a capacitance charge under the gate. A second structure for decreasing a capacitance under the gate includes an implant region in the semiconductor substrate between a channel region, where the implant region is doped to have a conductivity opposite the channel region.
    Type: Grant
    Filed: December 20, 1999
    Date of Patent: October 8, 2002
    Assignee: Fairchild Semiconductor Corporation
    Inventor: Daniel S. Calafut
  • Publication number: 20020102795
    Abstract: A power metal oxide semiconductor-field-effect-transistor (MOSFET) device using trench technology to achieve a reduced-mask-production process. The power MOSFET device includes a gate signal bus having multiple gate trenches formed using fewer masks than previously required for a similar device. The two-dimensional behavior of the trenches provides an advantageous field-coupling effect that suppresses hot-carrier generation without the need for the commonly used thick layer of silicon dioxide beneath the gate polysilicon. The use of easily controlled silicon trench etching in production of the power MOSFET results in stable, low cost, and high yielding manufacturing.
    Type: Application
    Filed: March 25, 2002
    Publication date: August 1, 2002
    Inventor: Daniel S. Calafut
  • Patent number: 6396102
    Abstract: A power metal oxide semiconductor-field-effect-transistor (MOSFET) device using trench technology to achieve a reduced-mask-production process. The power MOSFET device includes a gate signal bus having multiple gate trenches formed using fewer masks than previously required for a similar device. The two-dimensional behavior of the trenches provides an advantageous field-coupling effect that suppresses hot-carrier generation without the need for the commonly used thick layer of silicon dioxide beneath the gate poly-silicon. The use of easily controlled silicon trench etching in production of the power MOSFET results in stable, low cost, and high yielding manufacturing.
    Type: Grant
    Filed: January 27, 1998
    Date of Patent: May 28, 2002
    Assignee: Fairchild Semiconductor Corporation
    Inventor: Daniel S. Calafut
  • Patent number: 6229163
    Abstract: A method for utilizing fractal analysis in the design and manufacture of semiconductor structures including transistor devices such as power MOS devices. The method includes using fractal theory to determine optimum source perimeter values to increase aspect ratio. The method is implemented to allow for use of the theoretical values in conjunction with known photolithographic fabrication techniques. The resultant structure thus incorporates the theoretically derived values to approximate a fractal structure.
    Type: Grant
    Filed: November 20, 1998
    Date of Patent: May 8, 2001
    Assignee: Fairchild Semiconductor Corp.
    Inventor: Daniel S. Calafut
  • Patent number: 6153473
    Abstract: A structural enhancement to a conventional DMOS process flow addresses the well-known destructive latch up problem. The additional steps include a symmetric "deep" punch-through stopper implant and additional thermal budget to remove silicon damage and distribute the ionized dopants appropriately. The purpose of the implant is to create a low resistance base region within the parasitic bipolar transistor to prevent the device from activating under high current conditions. In terms of circuit characteristics, the goal is to lower the voltage drop at node Vx in FIG. 1C during avalanche breakdown. This structure also provides a means of suppressing the phenomena of punch-through breakdown which can also lower the device's voltage reading.
    Type: Grant
    Filed: October 13, 1998
    Date of Patent: November 28, 2000
    Assignee: National Semiconductor Corporation
    Inventors: Daniel S. Calafut, Steven P. Sapp