Patents by Inventor Vishnu Khemka

Vishnu Khemka 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: 20240113045
    Abstract: A semiconductor device has first and second current terminals and a control terminal that can be biased to form an electrically conductive path from the first current terminal to the second current terminal through a channel region is provided with a temperature-sensitive current limiting device. The current-limiting device is integrally formed from semiconductor material of the control terminal and is configured to cause a reduction in electrical current flowing through the channel region when the temperature of the device in the channel region exceeds a predetermined threshold temperature.
    Type: Application
    Filed: September 23, 2022
    Publication date: April 4, 2024
    Inventors: Tanuj Saxena, John Pigott, Vishnu Khemka, Ljubo Radic, Ganming Qin
  • Patent number: 11631763
    Abstract: A semiconductor device includes a substrate having opposed first and second major surface, an active area, and a termination area. Insulated trenches extend from the first major surface toward the second major surface, each of the insulated trenches including a conductive field plate and a gate electrode overlying the conductive field plate, the gate electrode being separated from the field plate by a gate-field plate insulator. The field plate extends longitudinally in both of the active and termination areas and the gate electrode is absent in the termination area. A body region of a first conductivity type extends laterally between pairs of the insulated trenches. First and second spacer regions of a second conductivity type extend laterally between the pairs of the insulated trenches at the termination area to produce segments of the first conductivity type between the first and second spacer regions that are isolated from the body region.
    Type: Grant
    Filed: April 4, 2022
    Date of Patent: April 18, 2023
    Assignee: NXP USA, Inc.
    Inventors: Tanuj Saxena, Vishnu Khemka, Bernhard Grote, Ganming Qin, Moaniss Zitouni
  • Publication number: 20220393004
    Abstract: A high voltage trench field plate power MOSFET device is fabricated in a substrate having first and second trenches separated from one another by a narrow epitaxial semiconductor drift pillar structure, where insulated gate electrode layers and insulated field plate layers are formed in the first and second trenches, and where a body well region is formed in an upper portion of the narrow epitaxial semiconductor drift pillar structure to include source contact regions in an active area, and to include an integrated ballast resistor section which connects one or more of the source contact regions to the termination area and which has no source contact regions.
    Type: Application
    Filed: May 26, 2022
    Publication date: December 8, 2022
    Inventors: Tanuj Saxena, Christian Torrent, Vishnu Khemka, Ganming Qin, Moaniss Zitouni
  • Patent number: 11489072
    Abstract: A MOSFET includes a substrate having a body region of a first conductivity type. A main field effect transistor (mainFET) and a mirror device are formed in the substrate. The mainFET includes first gate trenches, first source regions of a second conductivity type adjacent to the first gate trenches, and first body implant regions of the first conductivity type extending into the body region adjacent to and interposed between the first source regions. The mirror device includes second gate trenches, second source regions of the second conductivity type adjacent to the second gate trenches, second body implant regions of the first conductivity type extending into the body region adjacent to and interposed between the second source regions, and link elements of the first conductivity type interconnecting pairs of the second body implant regions.
    Type: Grant
    Filed: April 7, 2021
    Date of Patent: November 1, 2022
    Assignee: NXP USA, Inc.
    Inventors: Ganming Qin, Feng Li, Vishnu Khemka, Moaniss Zitouni, Tanuj Saxena
  • Publication number: 20220231161
    Abstract: A semiconductor device includes a substrate having opposed first and second major surface, an active area, and a termination area. Insulated trenches extend from the first major surface toward the second major surface, each of the insulated trenches including a conductive field plate and a gate electrode overlying the conductive field plate, the gate electrode being separated from the field plate by a gate-field plate insulator. The field plate extends longitudinally in both of the active and termination areas and the gate electrode is absent in the termination area. A body region of a first conductivity type extends laterally between pairs of the insulated trenches. First and second spacer regions of a second conductivity type extend laterally between the pairs of the insulated trenches at the termination area to produce segments of the first conductivity type between the first and second spacer regions that are isolated from the body region.
    Type: Application
    Filed: April 4, 2022
    Publication date: July 21, 2022
    Inventors: Tanuj Saxena, Vishnu Khemka, Bernhard Grote, Ganming Qin, Moaniss Zitouni
  • Patent number: 11329150
    Abstract: A semiconductor device includes a substrate having opposed first and second major surface, an active area, and a termination area. Insulated trenches extend from the first major surface toward the second major surface, each of the insulated trenches including a conductive field plate and a gate electrode overlying the conductive field plate, the gate electrode being separated from the field plate by a gate-field plate insulator. The field plate extends longitudinally in both of the active and termination areas and the gate electrode is absent in the termination area. A body region of a first conductivity type extends laterally between pairs of the insulated trenches. First and second spacer regions of a second conductivity type extend laterally between the pairs of the insulated trenches at the termination area to produce segments of the first conductivity type between the first and second spacer regions that are isolated from the body region.
    Type: Grant
    Filed: April 14, 2020
    Date of Patent: May 10, 2022
    Assignee: NXP USA, Inc.
    Inventors: Tanuj Saxena, Vishnu Khemka, Bernhard Grote, Ganming Qin, Moaniss Zitouni
  • Publication number: 20210320200
    Abstract: A semiconductor device includes a substrate having opposed first and second major surface, an active area, and a termination area. Insulated trenches extend from the first major surface toward the second major surface, each of the insulated trenches including a conductive field plate and a gate electrode overlying the conductive field plate, the gate electrode being separated from the field plate by a gate-field plate insulator. The field plate extends longitudinally in both of the active and termination areas and the gate electrode is absent in the termination area. A body region of a first conductivity type extends laterally between pairs of the insulated trenches. First and second spacer regions of a second conductivity type extend laterally between the pairs of the insulated trenches at the termination area to produce segments of the first conductivity type between the first and second spacer regions that are isolated from the body region.
    Type: Application
    Filed: April 14, 2020
    Publication date: October 14, 2021
    Inventors: Tanuj Saxena, Vishnu Khemka, Bernhard Grote, Ganming Qin, Moaniss Zitouni
  • Publication number: 20210226054
    Abstract: A MOSFET includes a substrate having a body region of a first conductivity type. A main field effect transistor (mainFET) and a mirror device are formed in the substrate. The mainFET includes first gate trenches, first source regions of a second conductivity type adjacent to the first gate trenches, and first body implant regions of the first conductivity type extending into the body region adjacent to and interposed between the first source regions. The mirror device includes second gate trenches, second source regions of the second conductivity type adjacent to the second gate trenches, second body implant regions of the first conductivity type extending into the body region adjacent to and interposed between the second source regions, and link elements of the first conductivity type interconnecting pairs of the second body implant regions.
    Type: Application
    Filed: April 7, 2021
    Publication date: July 22, 2021
    Inventors: Ganming Qin, Feng Li, Vishnu Khemka, Moaniss Zitouni, Tanuj Saxena
  • Patent number: 11004970
    Abstract: A MOSFET includes a substrate having a body region of a first conductivity type. A main field effect transistor (mainFET) and a mirror device are formed in the substrate. The mainFET includes first gate trenches, first source regions of a second conductivity type adjacent to the first gate trenches, and first body implant regions of the first conductivity type extending into the body region adjacent to and interposed between the first source regions. The mirror device includes second gate trenches, second source regions of the second conductivity type adjacent to the second gate trenches, second body implant regions of the first conductivity type extending into the body region adjacent to and interposed between the second source regions, and link elements of the first conductivity type interconnecting pairs of the second body implant regions.
    Type: Grant
    Filed: May 20, 2019
    Date of Patent: May 11, 2021
    Assignee: NXP USA, Inc.
    Inventors: Ganming Qin, Feng Li, Vishnu Khemka, Moaniss Zitouni, Tanuj Saxena
  • Publication number: 20200373426
    Abstract: A MOSFET includes a substrate having a body region of a first conductivity type. A main field effect transistor (mainFET) and a mirror device are formed in the substrate. The mainFET includes first gate trenches, first source regions of a second conductivity type adjacent to the first gate trenches, and first body implant regions of the first conductivity type extending into the body region adjacent to and interposed between the first source regions. The mirror device includes second gate trenches, second source regions of the second conductivity type adjacent to the second gate trenches, second body implant regions of the first conductivity type extending into the body region adjacent to and interposed between the second source regions, and link elements of the first conductivity type interconnecting pairs of the second body implant regions.
    Type: Application
    Filed: May 20, 2019
    Publication date: November 26, 2020
    Inventors: Ganming Qin, Feng Li, Vishnu Khemka, Moaniss Zitouni, Tanuj Saxena
  • Patent number: 10811502
    Abstract: A method for manufacturing a super-junction MOSFET entails forming a recessed shield electrode in a trench in a semiconductor layer of a substrate, the trench being lined with a first oxide layer. When the electrically conductive material forming the shield electrode is removed to recess the shield electrode, the first oxide layer on sidewalls of the trench is exposed. Removal of the first oxide layer from the sidewalls and from shield sidewalls of the electrode produces openings at a top part of the shield sidewalls. A second oxide layer is formed over the shield electrode and fills the openings. Part of the second oxide layer is removed to expose a top surface of the shield electrode. A gate dielectric is formed over the top surface of the shield electrode and conductive material is deposited over the gate dielectric in the trench to form a gate electrode of the MOSFET.
    Type: Grant
    Filed: May 30, 2019
    Date of Patent: October 20, 2020
    Assignee: NXP USA, Inc.
    Inventors: Vishnu Khemka, Tanuj Saxena, Ganming Qin, Raghuveer Vankayala Gupta, Mark Edward Gibson, Moaniss Zitouni
  • Publication number: 20200152786
    Abstract: A vertical bi-directional device includes first and second conductive gates in a semiconductor layer with a first vertical gate oxide on a sidewall of the first conductive gate and a second vertical gate oxide on a sidewall of the second conductive gate. A first heavily doped region of a first conductivity type is at the surface adjacent the first conductive gate, and a second heavily doped region of the first conductive type is at the surface adjacent to the second conductive gate. Doped regions of the first conductivity type extend below the conductive gates towards a substrate. A doped region of a second conductivity type extends laterally from the first vertical gate oxide to the second vertical gate oxide, and a heavily doped region of the second conductivity type is at the surface of the semiconductor layer, between the first and second heavily doped regions of the first conductivity type.
    Type: Application
    Filed: November 13, 2018
    Publication date: May 14, 2020
    Inventors: Moaniss ZITOUNI, Vishnu KHEMKA, Ganming QIN, Tanuj SAXENA, Raghuveer Vankayala GUPTA, Mark Edward GIBSON
  • Patent number: 10644146
    Abstract: A vertical bi-directional device includes first and second conductive gates in a semiconductor layer with a first vertical gate oxide on a sidewall of the first conductive gate and a second vertical gate oxide on a sidewall of the second conductive gate. A first heavily doped region of a first conductivity type is at the surface adjacent the first conductive gate, and a second heavily doped region of the first conductive type is at the surface adjacent to the second conductive gate. Doped regions of the first conductivity type extend below the conductive gates towards a substrate. A doped region of a second conductivity type extends laterally from the first vertical gate oxide to the second vertical gate oxide, and a heavily doped region of the second conductivity type is at the surface of the semiconductor layer, between the first and second heavily doped regions of the first conductivity type.
    Type: Grant
    Filed: November 13, 2018
    Date of Patent: May 5, 2020
    Assignee: NXP USA, Inc.
    Inventors: Moaniss Zitouni, Vishnu Khemka, Ganming Qin, Tanuj Saxena, Raghuveer Vankayala Gupta, Mark Edward Gibson
  • Patent number: 10600911
    Abstract: A transistor includes a trench formed in a semiconductor substrate. A gate electrode is formed in the trench with a first edge of the gate electrode proximate to a first sidewall of the trench. A first field plate is formed in the trench with the first field plate located between a second edge of the gate electrode and a second sidewall of the trench. A dielectric material is formed in the trench with the dielectric material having a first thickness between the first sidewall and a first edge of the first field plate, and a second thickness between the second sidewall and a second edge of the first field plate, the second thickness larger than the first thickness.
    Type: Grant
    Filed: September 26, 2017
    Date of Patent: March 24, 2020
    Assignee: NXP USA, INC.
    Inventors: Bernhard Grote, Saumitra Raj Mehrotra, Ljubo Radic, Vishnu Khemka, Mark Edward Gibson
  • Patent number: 10600879
    Abstract: A trench structure is located directly laterally between a first well and a first source region for a first transistor and the second well region with a second source for a second transistor. The trench structure includes a first gate structure for the first transistor, a second gate structure for the second transistor, a first conductive field plate structure, and a second conductive field plate structure. The first gate structure, the first field plate structure, the second field plate structure, and the second gate structure are located in the trench structure in a lateral line between the first well region and the second well region. The trench structure includes a dielectric separating the first field plate structure and the second field plate structure from each other in the lateral line. A drain region for the first transistor and the second transistor includes a portion located directly below the trench structure.
    Type: Grant
    Filed: March 12, 2018
    Date of Patent: March 24, 2020
    Assignee: NXP USA, INC.
    Inventors: Bernhard Grote, Saumitra Raj Mehrotra, Ljubo Radic, Vishnu Khemka
  • Patent number: 10431678
    Abstract: A plurality of trench stripes are disposed in parallel in an epitaxial layer on a drain and extends from a top region to a bottom region of a first surface of the semiconductor. A first polysilicon layer is in each of the trench stripes. The first polysilicon layer extends between the drain and the first surface proximal to the top region and the bottom region, and between the drain and a level below the first surface in a middle region between the top region and the bottom region. A second polysilicon layer is over the first polysilicon layer in the middle region, wherein the first poly silicon layer forms a shield, and the second polysilicon layer forms a gate. A source is in a silicon mesa stripe surrounding the first trench stripe.
    Type: Grant
    Filed: July 18, 2018
    Date of Patent: October 1, 2019
    Assignee: NXP USA, Inc.
    Inventors: Ganming Qin, Vishnu Khemka, Ljubo Radic, Bernhard Grote, Tanuj Saxena, Moaniss Zitouni
  • Publication number: 20190280094
    Abstract: A trench structure is located directly laterally between a first well and a first source region for a first transistor and the second well region with a second source for a second transistor. The trench structure includes a first gate structure for the first transistor, a second gate structure for the second transistor, a first conductive field plate structure, and a second conductive field plate structure. The first gate structure, the first field plate structure, the second field plate structure, and the second gate structure are located in the trench structure in a lateral line between the first well region and the second well region. The trench structure includes a dielectric separating the first field plate structure and the second field plate structure from each other in the lateral line. A drain region for the first transistor and the second transistor includes a portion located directly below the trench structure.
    Type: Application
    Filed: March 12, 2018
    Publication date: September 12, 2019
    Inventors: BERNHARD GROTE, Saumitra Raj Mehrotra, Ljubo Radic, Vishnu Khemka
  • Publication number: 20190148541
    Abstract: A plurality of trench stripes are disposed in parallel in an epitaxial layer on a drain and extends from a top region to a bottom region of a first surface of the semiconductor. A first polysilicon layer is in each of the trench stripes. The first polysilicon layer extends between the drain and the first surface proximal to the top region and the bottom region, and between the drain and a level below the first surface in a middle region between the top region and the bottom region. A second polysilicon layer is over the first polysilicon layer in the middle region, wherein the first poly silicon layer forms a shield, and the second polysilicon layer forms a gate. A source is in a silicon mesa stripe surrounding the first trench stripe.
    Type: Application
    Filed: July 18, 2018
    Publication date: May 16, 2019
    Inventors: Ganming Qin, Vishnu Khemka, Ljubo Radic, Bernhard Grote, Tanuj Saxena, Moaniss Zitouni
  • Publication number: 20190097045
    Abstract: A transistor includes a trench formed in a semiconductor substrate. A gate electrode is formed in the trench with a first edge of the gate electrode proximate to a first sidewall of the trench. A first field plate is formed in the trench with the first field plate located between a second edge of the gate electrode and a second sidewall of the trench. A dielectric material is formed in the trench with the dielectric material having a first thickness between the first sidewall and a first edge of the first field plate, and a second thickness between the second sidewall and a second edge of the first field plate, the second thickness larger than the first thickness.
    Type: Application
    Filed: September 26, 2017
    Publication date: March 28, 2019
    Inventors: BERNHARD GROTE, SAUMITRA RAJ MEHROTRA, LJUBO RADIC, VISHNU KHEMKA, MARK EDWARD GIBSON
  • Patent number: 10153357
    Abstract: A method for manufacturing a super junction power MOSFET includes forming a first trench in a substrate, forming a first oxide layer over the substrate and in the bottom and along sidewalls of the trench, depositing electrically conductive material in the trench, masking a first portion of the electrically conductive material, forming a recessed portion of the electrically conductive material, forming an oxide portion over and in contact with the recessed portion of the electrically conductive material, removing a part of the oxide portion by masking, removing the first oxide layer on the sidewalls while another part of the oxide portion remains in contact with the recessed portion of the electrically conductive material, forming a gate dielectric along exposed sidewalls of the trench, and depositing additional electrically conductive material over the other part of the oxide portion in the trench.
    Type: Grant
    Filed: August 28, 2017
    Date of Patent: December 11, 2018
    Assignee: NXP USA, Inc.
    Inventors: Ganming Qin, Vishnu Khemka, Tanuj Saxena, Moaniss Zitouni, Raghuveer Vankayala Gupta, Mark Edward Gibson