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: 20150069464
    Abstract: A lateral bipolar transistor with deep emitter and deep collector regions is formed using multiple epitaxial layers of the same conductivity type. Deep emitter and deep collector regions are formed without the use of trenches. Vertically aligned diffusion regions are formed in each epitaxial layer so that the diffusion regions merged into a contiguous diffusion region after annealing to function as emitter or collector or isolation structures. In another embodiment, a lateral trench PNP bipolar transistor is formed using trench emitter and trench collector regions. In yet another embodiment, a lateral PNP bipolar transistor with a merged LDMOS transistor is formed to achieve high performance.
    Type: Application
    Filed: November 12, 2014
    Publication date: March 12, 2015
    Inventors: Shekar Mallikarjunaswamy, Francois Hebert
  • Patent number: 8937356
    Abstract: An electrostatic discharge (ESD) protection circuit includes a triggering diode that includes a junction between a P-grade (PG) region and an N-well. The PG region has a dopant profile equivalent to a P-drain dopant profile of a PMOS transistor having a breakdown voltage represented by V whereby the triggering diode for conducting a current when a voltage greater than the breakdown voltage V is applied. In an exemplary embodiment, the dopant profile of the PG region includes two dopant implant profiles that include a shallow implant profile with a higher dopant concentration and a deep implant profile with a lower dopant concentration.
    Type: Grant
    Filed: April 5, 2011
    Date of Patent: January 20, 2015
    Assignee: Alpha Omega Semiconductor Inc.
    Inventor: Shekar Mallikarjunaswamy
  • Patent number: 8916951
    Abstract: A lateral bipolar transistor with deep emitter and deep collector regions is formed using multiple epitaxial layers of the same conductivity type. Deep emitter and deep collector regions are formed without the use of trenches. Vertically aligned diffusion regions are formed in each epitaxial layer so that the diffusion regions merged into a contiguous diffusion region after annealing to function as emitter or collector or isolation structures. In another embodiment, a lateral trench PNP bipolar transistor is formed using trench emitter and trench collector regions. In yet another embodiment, a lateral PNP bipolar transistor with a merged LDMOS transistor is formed to achieve high performance.
    Type: Grant
    Filed: September 23, 2011
    Date of Patent: December 23, 2014
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Shekar Mallikarjunaswamy, François Hébert
  • Patent number: 8889487
    Abstract: A three-dimensional (3D) gate driver integrated circuit includes a high-side integrated circuit stacked on a low-side integrated circuit where the high-side integrated circuit and the low-side integrated circuit are interconnected using through-silicon vias (TSV). As thus formed, the high-side integrated circuit and the low-side integrated circuit can be formed without termination regions and without buried layers. The 3D gate driver integrated circuit improves ease of high voltage integration and improves the ruggedness and reliability of the gate driver integrated circuit.
    Type: Grant
    Filed: June 24, 2014
    Date of Patent: November 18, 2014
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Shekar Mallikarjunaswamy
  • Publication number: 20140308784
    Abstract: A three-dimensional (3D) gate driver integrated circuit includes a high-side integrated circuit stacked on a low-side integrated circuit where the high-side integrated circuit and the low-side integrated circuit are interconnected using through-silicon vias (TSV). As thus formed, the high-side integrated circuit and the low-side integrated circuit can be formed without termination regions and without buried layers. The 3D gate driver integrated circuit improves ease of high voltage integration and improves the ruggedness and reliability of the gate driver integrated circuit.
    Type: Application
    Filed: June 24, 2014
    Publication date: October 16, 2014
    Inventor: Shekar Mallikarjunaswamy
  • Publication number: 20140268441
    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: Application
    Filed: March 13, 2013
    Publication date: September 18, 2014
    Applicant: ALPHA AND OMEGA SEMICONDUCTOR INCORPORATED
    Inventor: Shekar Mallikarjunaswamy
  • Patent number: 8816476
    Abstract: The present invention features a field effect transistor forming on a semiconductor substrate having formed thereon gate, source and drain regions, with said gate region having a lateral gate channel. A plurality of spaced-apart trenches each having an electrically conductive plug formed therein in electrical communication with said gate, source and drain regions, with said trenches extend from a back surface of said semiconductor substrate to a controlled depth. A trench contact shorts the source region and a body region. A source contact is in electrical communication with said source region and a drain contact in electrical communication with said drain region, with said source and drain contacts being disposed on opposite sides of said gate channel.
    Type: Grant
    Filed: April 27, 2011
    Date of Patent: August 26, 2014
    Assignee: Alpha & Omega Semiconductor Corporation
    Inventor: Shekar Mallikarjunaswamy
  • Publication number: 20140225190
    Abstract: A semiconductor device with multiple transistor devices 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 being an LDMOS transistor formed in the semiconductor layer between the first trench and the second trench; and a second transistor device formed in the semiconductor layer on the other side of the second trench. The first transistor device is electrically isolated from the second transistor device by the second trench.
    Type: Application
    Filed: March 4, 2014
    Publication date: August 14, 2014
    Applicant: Alpha and Omega Semiconductor Incorporated
    Inventor: Shekar Mallikarjunaswamy
  • Patent number: 8791723
    Abstract: A three-dimensional (3D) gate driver integrated circuit includes a high-side integrated circuit stacked on a low-side integrated circuit where the high-side integrated circuit and the low-side integrated circuit are interconnected using through-silicon vias (TSV). As thus formed, the high-side integrated circuit and the low-side integrated circuit can be formed without termination regions and without buried layers. The 3D gate driver integrated circuit improves ease of high voltage integration and improves the ruggedness and reliability of the gate driver integrated circuit.
    Type: Grant
    Filed: August 17, 2012
    Date of Patent: July 29, 2014
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Shekar Mallikarjunaswamy
  • Publication number: 20140167218
    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: December 19, 2012
    Publication date: June 19, 2014
    Inventors: Shekar Mallikarjunaswamy, Madhur Bobde
  • Patent number: 8704303
    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. The planar gate forms a lateral channel in the body region, and the trench gate in the first trench forms a vertical channel in the body region of the LDMOS transistor.
    Type: Grant
    Filed: January 10, 2013
    Date of Patent: April 22, 2014
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Shekar Mallikarjunaswamy
  • Publication number: 20140049293
    Abstract: A three-dimensional (3D) gate driver integrated circuit includes a high-side integrated circuit stacked on a low-side integrated circuit where the high-side integrated circuit and the low-side integrated circuit are interconnected using through-silicon vias (TSV). As thus formed, the high-side integrated circuit and the low-side integrated circuit can be formed without termination regions and without buried layers.
    Type: Application
    Filed: August 17, 2012
    Publication date: February 20, 2014
    Applicant: ALPHA & OMEGA SEMICONDUCTOR, INC.
    Inventor: Shekar Mallikarjunaswamy
  • Patent number: 8643137
    Abstract: A short channel Lateral MOSFET (LMOS) and method are disclosed with interpenetrating drain-body protrusions (IDBP) for reducing channel-on resistance while maintaining high punch-through voltage. The LMOS includes lower device bulk layer; upper source and upper drain region both located atop lower device bulk layer; both upper source and upper drain region are in contact with an intervening upper body region atop lower device bulk layer; both upper drain and upper body region are shaped to form a drain-body interface; the drain-body interface has an IDBP structure with a surface drain protrusion lying atop a buried body protrusion while revealing a top body surface area of the upper body region; gate oxide-gate electrode bi-layer disposed atop the upper body region forming an LMOS with a short channel length defined by the horizontal length of the top body surface area delineated between the upper source region and the upper drain region.
    Type: Grant
    Filed: June 4, 2012
    Date of Patent: February 4, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Shekar Mallikarjunaswamy, Amit Paul
  • Patent number: 8542470
    Abstract: This invention discloses a transient voltage suppressing (TVS) circuit that includes a triggering Zener diode connected between an emitter and a collector of a bipolar-junction transistor (BJT) wherein the Zener diode having a reverse breakdown voltage BV less than or equal to a BVceo of the BJT where BVceo stands for a collector to emitter breakdown voltage with base left open. The TVS circuit further includes a rectifier connected in parallel to the BJT for triggering a rectified current through the rectifier for further limiting an increase of a reverse blocking voltage. The triggering Zener diode, the BJT and the rectifier are formed in a semiconductor substrate by implanting and configuring dopant regions of a first and a second conductivity types in an N-well and a P-well whereby the TVS can be formed in parallel as part of the manufacturing processes of the electronic device.
    Type: Grant
    Filed: January 16, 2012
    Date of Patent: September 24, 2013
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Shekar Mallikarjunaswamy
  • Patent number: 8503141
    Abstract: This invention discloses an electronic device formed as an integrated circuit (IC) wherein the electronic device further includes a transient voltage suppressing (TVS) circuit for suppressing a transient voltage. The transient voltage suppressing (TVS) circuit includes a Zener diode connected between a ground terminal and a node for triggering a snapback circuit. In one embodiment, this node may be a Vcc terminal. The TVS device further includes a snapback circuit connected in parallel to the Zener diode for conducting a transient voltage current with a snapback current-voltage (I-V) characteristic upon turning on of the snapback circuit. And, the TVS device further includes a snapback suppressing circuit connected in series with the snapback circuit for conducting a current with an I-V characteristic complementary to the snapback-IV characteristic for clamping a snapback voltage.
    Type: Grant
    Filed: July 10, 2012
    Date of Patent: August 6, 2013
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Shekar Mallikarjunaswamy
  • Publication number: 20130075746
    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: September 23, 2011
    Publication date: March 28, 2013
    Applicant: ALPHA AND OMEGA SEMICONDUCTOR INC.
    Inventors: Shekar Mallikarjunaswamy, François Hébert
  • Publication number: 20130075741
    Abstract: A lateral bipolar transistor with deep emitter and deep collector regions is formed using multiple epitaxial layers of the same conductivity type. Deep emitter and deep collector regions are formed without the use of trenches. Vertically aligned diffusion regions are formed in each epitaxial layer so that the diffusion regions merged into a contiguous diffusion region after annealing to function as emitter or collector or isolation structures. In another embodiment, a lateral trench PNP bipolar transistor is formed using trench emitter and trench collector regions. In yet another embodiment, a lateral PNP bipolar transistor with a merged LDMOS transistor is formed to achieve high performance.
    Type: Application
    Filed: September 23, 2011
    Publication date: March 28, 2013
    Applicant: ALPHA AND OMEGA SEMICONDUCTOR INC.
    Inventors: Shekar Mallikarjunaswamy, François Hébert
  • Patent number: 8378420
    Abstract: A vertical trench LDMOS transistor includes a semiconductor layer of a first conductivity type; a first trench formed in the semiconductor layer and filled with a trench dielectric and a trench gate is formed in the first trench; a body region of a second conductivity type formed in the semiconductor layer adjacent the first trench; a source region formed in the body region and adjacent the first trench; a planar gate insulated from the semiconductor layer by a second gate dielectric layer and overlying the body region; and a drain drift region formed in the semiconductor layer. The planar gate forms a lateral channel in the body region between the source region and the drain drift region, and the trench gate in the first trench forms a vertical channel in the body region along the sidewall of the first trench between the source region and the semiconductor layer.
    Type: Grant
    Filed: April 5, 2012
    Date of Patent: February 19, 2013
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Shekar Mallikarjunaswamy
  • Publication number: 20130016446
    Abstract: This invention discloses a transient voltage suppressing (TVS) circuit that includes a triggering Zener diode connected between an emitter and a collector of a bipolar-junction transistor (BJT) wherein the Zener diode having a reverse breakdown voltage BV less than or equal to a BVceo of the BJT where BVceo stands for a collector to emitter breakdown voltage with base left open. The TVS circuit further includes a rectifier connected in parallel to the BJT for triggering a rectified current through the rectifier for further limiting an increase of a reverse blocking voltage. The triggering Zener diode, the BJT and the rectifier are formed in a semiconductor substrate by implanting and configuring dopant regions of a first and a second conductivity types in an N-well and a P-well whereby the TVS can be formed in parallel as part of the manufacturing processes of the electronic device.
    Type: Application
    Filed: January 16, 2012
    Publication date: January 17, 2013
    Inventor: Shekar Mallikarjunaswamy
  • Publication number: 20120281329
    Abstract: This invention discloses an electronic device formed as an integrated circuit (IC) wherein the electronic device further includes a transient voltage suppressing (TVS) circuit for suppressing a transient voltage. The transient voltage suppressing (TVS) circuit includes a Zener diode connected between a ground terminal and a node for triggering a snapback circuit. In one embodiment, this node may be a Vcc terminal. The TVS device further includes a snapback circuit connected in parallel to the Zener diode for conducting a transient voltage current with a snapback current-voltage (I-V) characteristic upon turning on of the snapback circuit. And, the TVS device further includes a snapback suppressing circuit connected in series with the snapback circuit for conducting a current with an I-V characteristic complementary to the snapback-IV characteristic for clamping a snapback voltage.
    Type: Application
    Filed: July 10, 2012
    Publication date: November 8, 2012
    Inventor: Shekar Mallikarjunaswamy