Patents by Inventor Shekar Mallikarjunaswamy

Shekar Mallikarjunaswamy 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: 20180076319
    Abstract: A closed cell lateral MOSFET device includes minimally sized source/body contacts formed in source cells with silicided source and body diffusion regions formed therein. In this manner, the cell pitch of the cellular transistor array is kept small while the ruggedness of the transistor is ensured. In other embodiments, a closed cell lateral MOSFET device is formed using silicided source and body diffusion regions and self-aligned contacts or borderless contacts as the source/body contacts. The polysilicon gate mesh can be formed using minimum polysilicon-to-polysilicon spacing to minimize the cell pitch of the cellular transistor array.
    Type: Application
    Filed: November 16, 2017
    Publication date: March 15, 2018
    Inventor: Shekar Mallikarjunaswamy
  • Publication number: 20180062386
    Abstract: A MOSFET and an electrostatic discharge (ESD) protection device on a common chip includes a MOSFET with a source, a gate, and a drain, and an ESD protection device configured to implement a diode function that is biased to prevent current from flowing through the common chip from the source to the drain.
    Type: Application
    Filed: August 23, 2016
    Publication date: March 1, 2018
    Inventor: Shekar Mallikarjunaswamy
  • Patent number: 9899471
    Abstract: An integrated circuit uses a compact CMOS device isolation scheme which forms a ring of N-well housing PMOS devices to encircle the P-well housing NMOS devices in a circuit block. An N-type buried layer is formed under the P-well and extends partially under the surrounding N-well. The compact CMOS device isolation scheme eliminates the use of a deep N-well ring around the circuit block. Therefore, the circuit blocks of the integrated circuit can be formed with reduced silicon area and the die size for implementing the integrated circuit is reduced.
    Type: Grant
    Filed: December 8, 2016
    Date of Patent: February 20, 2018
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Shekar Mallikarjunaswamy
  • Publication number: 20170373158
    Abstract: A vertical TVS (VTVS) circuit includes a semiconductor substrate for supporting the VTVS device thereon having a heavily doped layer extending to the bottom of substrate. Deep trenches are provided for isolation between multi-channel VTVS. Trench gates are also provided for increasing the capacitance of VTVS with integrated EMI filter.
    Type: Application
    Filed: August 20, 2017
    Publication date: December 28, 2017
    Inventors: Shekar Mallikarjunaswamy, Madhur Bobde
  • Patent number: 9853143
    Abstract: A closed cell lateral MOSFET device includes minimally sized source/body contacts formed in source cells with silicided source and body diffusion regions formed therein. In this manner, the cell pitch of the cellular transistor array is kept small while the ruggedness of the transistor is ensured. In other embodiments, a closed cell lateral MOSFET device is formed using silicided source and body diffusion regions and self-aligned contacts or borderless contacts as the source/body contacts. The polysilicon gate mesh can be formed using minimum polysilicon-to-polysilicon spacing to minimize the cell pitch of the cellular transistor array.
    Type: Grant
    Filed: April 11, 2016
    Date of Patent: December 26, 2017
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Shekar Mallikarjunaswamy
  • Patent number: 9837400
    Abstract: A power integrated circuit includes a double-diffused metal-oxide-semiconductor (LDMOS) transistor formed in a first portion of the semiconductor layer with a channel being formed in a first body region. The power integrated circuit includes a first deep diffusion region formed in the first deep well under the first body region and in electrical contact with the first body region and a second deep diffusion region formed in the first deep well under the drain drift region and in electrical contact with the first body region. The first deep diffusion region and the second deep diffusion region together form a reduced surface field (RESURF) structure in the LDMOS transistor.
    Type: Grant
    Filed: September 7, 2016
    Date of Patent: December 5, 2017
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Shekar Mallikarjunaswamy
  • Patent number: 9837386
    Abstract: A power conversion device including a low-side MOSFET, a high-side MOSFET and an integrated control IC chip is disclosed. The power conversion device further includes a substrate comprising a first mounting area having a first group of welding discs and a second mounting area having a second group of welding discs; a first chip flipped and attached to the first mounting area; a second chip flipped and attached to the second mounting area; a metal clip; and a molding body covering a front surface of the substrate, the first chip, the second chip and the metal clip. Metal pads on a front side of the first chip is attached to the first group of welding discs. Metal pads on a front side of the second chip is attached to the second group of welding discs. The metal clip connects a connection pad to a back metal layer of the first chip.
    Type: Grant
    Filed: January 12, 2016
    Date of Patent: December 5, 2017
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR INCORPORATED
    Inventors: Xiaotian Zhang, Shekar Mallikarjunaswamy, Zhiqiang Niu, Cheow Khoon Oh, Yueh-Se Ho
  • Publication number: 20170263727
    Abstract: A lateral bipolar transistor includes trench emitter and trench collector regions to form ultra-narrow emitter regions, thereby improving emitter efficiency. The same trench process is used to form the emitter/collector trenches as well as the trench isolation structures so that no additional processing steps are needed to form the trench emitter and collector. In embodiments of the present invention, the trench emitter and trench collector regions may be formed using ion implantation into trenches formed in a semiconductor layer. In other embodiments, the trench emitter and trench collector regions may be formed by out-diffusion of dopants from heavily doped polysilicon filled trenches.
    Type: Application
    Filed: May 30, 2017
    Publication date: September 14, 2017
    Inventors: Shekar Mallikarjunaswamy, Francois Hebert
  • Patent number: 9748346
    Abstract: A vertical TVS (VTVS) circuit includes a semiconductor substrate for supporting the VTVS device thereon having a heavily doped layer extending to the bottom of substrate. Deep trenches are provided for isolation between multi-channel VTVS. Trench gates are also provided for increasing the capacitance of VTVS with integrated EMI filter.
    Type: Grant
    Filed: November 25, 2014
    Date of Patent: August 29, 2017
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Shekar Mallikarjunaswamy, Madhur Bobde
  • Publication number: 20170213894
    Abstract: A dual channel trench LDMOS transistor includes a semiconductor layer of a first conductivity type formed on a substrate; a first trench formed in the semiconductor layer where a trench gate is formed in an upper portion of the first trench; a body region of the second conductivity type formed in the semiconductor layer adjacent the first trench; a source region of the first conductivity type formed in the body region and adjacent the first trench; a planar gate overlying the body region; a drain drift region of the first conductivity type formed in the semiconductor layer and in electrical contact with a drain electrode; and alternating N-type and P-type regions formed in the drain drift region with higher doping concentration than the drain-drift regions to form a super-junction structure in the drain drift region.
    Type: Application
    Filed: February 1, 2017
    Publication date: July 27, 2017
    Inventor: Shekar Mallikarjunaswamy
  • Publication number: 20170200705
    Abstract: A power device including a low-side MOSFET, a high-side MOSFET and an integrated control IC chip is disclosed. The power device further includes a substrate comprising a first mounting area having a first group of welding discs and a second mounting area having a second group of welding discs; a first chip flipped and attached to the first mounting area; a second chip flipped and attached to the second mounting area; a metal clip; and a molding body covering a front surface of the substrate, the first chip, the second chip and the metal clip. Metal pads on a front side of the first chip is attached to the first group of welding discs. Metal pads on a front side of the second chip is attached to the second group of welding discs. The metal clip connects a connection pad to a back metal layer of the first chip.
    Type: Application
    Filed: January 12, 2016
    Publication date: July 13, 2017
    Applicant: Alpha and Omega Semiconductor Incorporated
    Inventors: Xiaotian Zhang, Shekar Mallikarjunaswamy, Zhiqiang Niu, Cheow Khoon Oh, Yueh-Se Ho
  • Patent number: 9698237
    Abstract: A lateral bipolar transistor includes trench emitter and trench collector regions to form ultra-narrow emitter regions, thereby improving emitter efficiency. The same trench process is used to form the emitter/collector trenches as well as the trench isolation structures so that no additional processing steps are needed to form the trench emitter and collector. In embodiments of the present invention, the trench emitter and trench collector regions may be formed using ion implantation into trenches formed in a semiconductor layer. In other embodiments, the trench emitter and trench collector regions may be formed by out-diffusion of dopants from heavily doped polysilicon filled trenches.
    Type: Grant
    Filed: March 1, 2016
    Date of Patent: July 4, 2017
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Shekar Mallikarjunaswamy, Francois Hebert
  • Patent number: 9685443
    Abstract: An integrated circuit includes an active device formed in a semiconductor layer of a first conductivity type, a first guard ring of the first conductivity type formed in the semiconductor layer surrounding at least part of the active device; a second guard ring of the second conductivity type formed in the semiconductor layer surrounding the first guard ring and the active device and including comprising alternating first well regions of the first conductivity type and the second well regions of the second conductivity type, the first and second well regions being electrically shorted together and electrically coupled to a ground potential or floating; and a third guard ring of the first conductivity type formed in the semiconductor layer surrounding the second guard ring. The first and third guard rings do not receive direct electrical connection.
    Type: Grant
    Filed: May 24, 2016
    Date of Patent: June 20, 2017
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Shekar Mallikarjunaswamy
  • Publication number: 20170154957
    Abstract: An integrated circuit uses a compact CMOS device isolation scheme which forms a ring of N-well housing PMOS devices to encircle the P-well housing NMOS devices in a circuit block. An N-type buried layer is formed under the P-well and extends partially under the surrounding N-well. The compact CMOS device isolation scheme eliminates the use of a deep N-well ring around the circuit block. Therefore, the circuit blocks of the integrated circuit can be formed with reduced silicon area and the die size for implementing the integrated circuit is reduced.
    Type: Application
    Filed: December 8, 2016
    Publication date: June 1, 2017
    Inventor: Shekar Mallikarjunaswamy
  • Publication number: 20170141225
    Abstract: In an embodiment, this invention discloses a top-drain lateral diffusion metal oxide field effect semiconductor (TD-LDMOS) device supported on a semiconductor substrate. The TD-LDMOS includes a source electrode disposed on a bottom surface of the semiconductor substrate. The TD-LDMOS further includes a source region and a drain region disposed on two opposite sides of a planar gate disposed on a top surface of the semiconductor substrate wherein the source region is encompassed in a body region constituting a drift region as a lateral current channel between the source region and drain region under the planar gate. The TD-LDMOS further includes at least a trench filled with a conductive material and extending vertically from the body region near the top surface downwardly to electrically contact the source electrode disposed on the bottom surface of the semiconductor substrate.
    Type: Application
    Filed: September 12, 2015
    Publication date: May 18, 2017
    Inventors: Shekar Mallikarjunaswamy, John Chen, Yongzhong Hu
  • Patent number: 9595517
    Abstract: A semiconductor device includes a semiconductor layer of a first conductivity type formed on a substrate; a first trench formed in the semiconductor layer including a first trench gate; a second trench formed in the semiconductor layer and extending into the substrate and including a second trench gate; a first transistor device formed in the semiconductor layer adjacent the first trench. The second trench encircles active area of the first transistor device to provide electrical isolation of the first transistor device.
    Type: Grant
    Filed: October 12, 2015
    Date of Patent: March 14, 2017
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Shekar Mallikarjunaswamy
  • Publication number: 20170062415
    Abstract: A power integrated circuit includes a double-diffused metal-oxide-semiconductor (LDMOS) transistor formed in a first portion of the semiconductor layer with a channel being formed in a first body region. The power integrated circuit includes a first deep diffusion region formed in the first deep well under the first body region and in electrical contact with the first body region and a second deep diffusion region formed in the first deep well under the drain drift region and in electrical contact with the first body region. The first deep diffusion region and the second deep diffusion region together form a reduced surface field (RESURF) structure in the LDMOS transistor.
    Type: Application
    Filed: September 7, 2016
    Publication date: March 2, 2017
    Inventor: Shekar Mallikarjunaswamy
  • Patent number: 9548307
    Abstract: An integrated circuit includes a first well of the first conductivity type formed in a semiconductor layer where the first well housing active devices and being connected to a first well potential, a second well of a second conductivity type formed in the semiconductor layer and encircling the first well where the second well housing active devices and being connected to a second well potential, and a buried layer of the second conductivity type formed under the first well and overlapping at least partially the second well encircling the first well. In an alternate embodiment, instead of the buried layer, the integrated circuit includes a third well of the second conductivity type formed in the semiconductor layer where the third well contains the first well and overlaps at least partially the second well encircling the first well.
    Type: Grant
    Filed: June 30, 2014
    Date of Patent: January 17, 2017
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Shekar Mallikarjunaswamy
  • Publication number: 20160358917
    Abstract: An integrated circuit includes an active device formed in a semiconductor layer of a first conductivity type, a first guard ring of the first conductivity type formed in the semiconductor layer surrounding at least part of the active device; a second guard ring of the second conductivity type formed in the semiconductor layer surrounding the first guard ring and the active device and including comprising alternating first well regions of the first conductivity type and the second well regions of the second conductivity type, the first and second well regions being electrically shorted together and electrically coupled to a ground potential or floating; and a third guard ring of the first conductivity type formed in the semiconductor layer surrounding the second guard ring. The first and third guard rings do not receive direct electrical connection.
    Type: Application
    Filed: May 24, 2016
    Publication date: December 8, 2016
    Inventor: Shekar Mallikarjunaswamy
  • Patent number: 9466972
    Abstract: A high-voltage gate driver circuit configured to drive a high-side power switch and a low-side power switch includes an active dv/dt triggered ESD protection circuit coupled between a protected node and a power rail node. The active dv/dt triggered ESD protection circuit includes a dv/dt circuit controlling an ESD protection transistor connected between the protected node and the power rail node. The ESD protection transistor is turned on when an ESD event occurs at the protected node to conduct ESD current from the protected node to the power rail node. The dv/dt circuit is charged up after a time constant to disable the ESD protection transistor.
    Type: Grant
    Filed: August 5, 2015
    Date of Patent: October 11, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Shekar Mallikarjunaswamy