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).

  • Patent number: 9460926
    Abstract: A power integrated circuit includes a junction field effect transistor (JFET) device formed in a first portion of a semiconductor layer with a gate region being formed using a first body region, and a double-diffused metal-oxide-semiconductor (LDMOS) transistor formed in a second portion of the semiconductor layer with a channel being formed in a second body region. The power integrated circuit includes a first deep diffusion region formed under the first body region and in electrical contact with the first body region where the first deep diffusion region together with the firs body region establish a pinch off voltage of the JFET device; and a second deep diffusion region formed under the second body region and in electrical contact with the second body region where the second deep diffusion region forms a reduced surface field (RESURF) structure in the LDMOS transistor.
    Type: Grant
    Filed: June 30, 2014
    Date of Patent: October 4, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Shekar Mallikarjunaswamy
  • Patent number: 9437673
    Abstract: Aspects of the present disclosure describe an integrated circuit comprises a substrate of a first conductivity type semiconductor, a lightly doped semiconductor layer of the first conductivity type semiconductor disposed over the substrate, a driver circuit, an electrically conductive interconnect structure formed over the semiconductor layer and electrically connected to the driver circuit at one end, at least one guard structure formed in the semiconductor layer and under the interconnect structure and a well region of the first conductivity type semiconductor formed in a top portion of the semiconductor layer, between the driver circuit and the at least one guard structure and under the interconnect structure. The guard structure is electrically floating. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure.
    Type: Grant
    Filed: February 5, 2014
    Date of Patent: September 6, 2016
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR INCORPORATED
    Inventor: Shekar Mallikarjunaswamy
  • Publication number: 20160247895
    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: March 1, 2016
    Publication date: August 25, 2016
    Inventors: Shekar Mallikarjunaswamy, Francois Hebert
  • Publication number: 20160225898
    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: April 11, 2016
    Publication date: August 4, 2016
    Inventor: Shekar Mallikarjunaswamy
  • Patent number: 9373682
    Abstract: An integrated circuit includes a guard ring structure including a guard ring with integrated well taps to reduce the silicon area required for the guard ring structure. In some embodiments, the guard ring structure includes an N-type guard ring surrounded by inner and outer P-type guard rings. The N-type guard ring is formed with interleaving deep N-wells and P-wells that are formed on an N-type buried layer and are electrically shorted together. The inner and outer P-type guard rings are formed in P-wells. The interleaving deep N-wells and P-wells of the N-type guard ring may be connected to ground or be left floating. By integrating P-well contacts in the N-type guard ring, P-well contacts, or P-taps, for the P-type guard ring can be eliminated.
    Type: Grant
    Filed: June 30, 2014
    Date of Patent: June 21, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Shekar Mallikarjunaswamy
  • Patent number: 9355971
    Abstract: In some embodiment, a fuse structure in a semiconductor device uses a metal fuse element connected to a stacked via fuse link connected to a thin film resistive element. The fuse structure can be incorporated in an integrated circuit for EOS protection. In other embodiments, an integrated EOS/ESD protection circuit includes a current limiting resistor integrated with an ESD protection circuit. In some embodiments, the current limiting resistor is formed in an N-well forming the collector of the ESD protection circuit.
    Type: Grant
    Filed: June 23, 2015
    Date of Patent: May 31, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Shekar Mallikarjunaswamy
  • Patent number: 9337284
    Abstract: A closed cell lateral MOSFET device includes minimally sized source/body contacts formed in one or more 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 7, 2014
    Date of Patent: May 10, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Shekar Mallikarjunaswamy
  • Patent number: 9312335
    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: September 23, 2011
    Date of Patent: April 12, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Shekar Mallikarjunaswamy, François Hébert
  • Publication number: 20160099242
    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: Application
    Filed: October 12, 2015
    Publication date: April 7, 2016
    Inventor: Shekar Mallikarjunaswamy
  • Publication number: 20150380398
    Abstract: A power integrated circuit includes a junction field effect transistor (JFET) device formed in a first portion of a semiconductor layer with a gate region being formed using a first body region, and a double-diffused metal-oxide-semiconductor (LDMOS) transistor formed in a second portion of the semiconductor layer with a channel being formed in a second body region. The power integrated circuit includes a first deep diffusion region formed under the first body region and in electrical contact with the first body region where the first deep diffusion region together with the firs body region establish a pinch off voltage of the JFET device; and a second deep diffusion region formed under the second body region and in electrical contact with the second body region where the second deep diffusion region forms a reduced surface field (RESURF) structure in the LDMOS transistor.
    Type: Application
    Filed: June 30, 2014
    Publication date: December 31, 2015
    Inventor: Shekar Mallikarjunaswamy
  • Publication number: 20150380483
    Abstract: An integrated circuit includes a guard ring structure including a guard ring with integrated well taps to reduce the silicon area required for the guard ring structure. In some embodiments, the guard ring structure includes an N-type guard ring surrounded by inner and outer P-type guard rings. The N-type guard ring is formed with interleaving deep N-wells and P-wells that are formed on an N-type buried layer and are electrically shorted together. The inner and outer P-type guard rings are formed in P-wells. The interleaving deep N-wells and P-wells of the N-type guard ring may be connected to ground or be left floating. By integrating P-well contacts in the N-type guard ring, P-well contacts, or P-taps, for the P-type guard ring can be eliminated.
    Type: Application
    Filed: June 30, 2014
    Publication date: December 31, 2015
    Inventor: Shekar Mallikarjunaswamy
  • Publication number: 20150380413
    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: Application
    Filed: June 30, 2014
    Publication date: December 31, 2015
    Inventor: Shekar Mallikarjunaswamy
  • Patent number: 9214534
    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: November 12, 2014
    Date of Patent: December 15, 2015
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Shekar Mallikarjunaswamy, Francois Hebert
  • Publication number: 20150340856
    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: August 5, 2015
    Publication date: November 26, 2015
    Inventor: Shekar Mallikarjunaswamy
  • Patent number: 9190408
    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: Grant
    Filed: March 4, 2014
    Date of Patent: November 17, 2015
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Shekar Mallikarjunaswamy
  • Patent number: 9159828
    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: Grant
    Filed: March 30, 2012
    Date of Patent: October 13, 2015
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Shekar Mallikarjunaswamy, John Chen, YongZhong Hu
  • Publication number: 20150287820
    Abstract: A closed cell lateral MOSFET device includes minimally sized source/body contacts formed in one or more 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: April 7, 2014
    Publication date: October 8, 2015
    Applicant: Alpha and Omega Semiconductor Incorporated
    Inventor: Shekar Mallikarjunaswamy
  • Patent number: 9130562
    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: March 13, 2013
    Date of Patent: September 8, 2015
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Shekar Mallikarjunaswamy
  • Patent number: 9118322
    Abstract: A bidirectional switch device includes a main pass field effect transistor (FET) connected to an input node and an output node. A body region of the first main pass transistor is tied to a voltage substantially halfway between the voltage at the input node side of the first main pass transistor and the voltage at the output node side of the transistor when the first main pass transistor is in an ON state.
    Type: Grant
    Filed: February 24, 2011
    Date of Patent: August 25, 2015
    Assignee: Alpha and Omega Semiconductor (Cayman) LTD
    Inventors: Mohammad Suhaib Husain, Shekar Mallikarjunaswamy
  • Publication number: 20150221720
    Abstract: Aspects of the present disclosure describe an integrated circuit comprises a substrate of a first conductivity type semiconductor, a lightly doped semiconductor layer of the first conductivity type semiconductor disposed over the substrate, a driver circuit, an electrically conductive interconnect structure formed over the semiconductor layer and electrically connected to the driver circuit at one end, at least one guard structure formed in the semiconductor layer and under the interconnect structure and a well region of the first conductivity type semiconductor formed in a top portion of the semiconductor layer, between the driver circuit and the at least one guard structure and under the interconnect structure. The guard structure is electrically floating. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure.
    Type: Application
    Filed: February 5, 2014
    Publication date: August 6, 2015
    Applicant: Alpha and Omega Semiconductor Incorporated
    Inventor: Shekar Mallikarjunaswamy