Patents by Inventor Anup Bhalla

Anup Bhalla 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: 20170053989
    Abstract: A termination structure with multiple embedded potential spreading capacitive structures (TSMEC) and method are disclosed for terminating an adjacent trench MOSFET atop a bulk semiconductor layer (BSL) with bottom drain electrode. The BSL has a proximal bulk semiconductor wall (PBSW) supporting drain-source voltage (DSV) and separating TSMEC from trench MOSFET. The TSMEC has oxide-filled large deep trench (OFLDT) bounded by PBSW and a distal bulk semiconductor wall (DBSW). The OFLDT includes a large deep oxide trench into the BSL and embedded capacitive structures (EBCS) located inside the large deep oxide trench and between PBSW and DBSW for spatially spreading the DSV across them. In one embodiment, the EBCS contains interleaved conductive embedded polycrystalline semiconductor regions (EPSR) and oxide columns (OXC) of the OFLDT, a proximal EPSR next to PBSW is connected to an active upper source region and a distal EPSR next to DBSW is connected to the DBSW.
    Type: Application
    Filed: April 13, 2015
    Publication date: February 23, 2017
    Inventors: Xiaobin Wang, Anup Bhalla, Hamza Yilmaz, Daniel Ng
  • Patent number: 9577072
    Abstract: The present disclosure describes a termination structure for a high voltage semiconductor transistor device. The termination structure is composed of at least two termination zones and an electrical disconnection between the body layer and the edge of the device. A first zone is configured to spread the electric field within the device. A second zone is configured to smoothly bring the electric field back up to the top surface of the device. The electrical disconnection prevents the device from short circuiting the edge of the device. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
    Type: Grant
    Filed: June 12, 2015
    Date of Patent: February 21, 2017
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR INCORPORATED
    Inventors: Lingpeng Guan, Anup Bhalla, Hamza Yilmaz
  • Patent number: 9570404
    Abstract: A semiconductor power device comprises a plurality of power transistor cells each having a trenched gate disposed in a gate trench wherein the trenched gate comprising a shielding bottom electrode disposed in a bottom portion of the gate trench electrically insulated from a top gate electrode disposed in a top portion of the gate trench by an inter-electrode insulation layer. At least one of the transistor cells includes the shielding bottom electrode functioning as a source-connecting shielding bottom electrode electrically connected to a source electrode of the semiconductor power device and at least one of the transistor cells having the shielding bottom electrode functioning as a gate-connecting shielding bottom electrode electrically connected to a gate metal of the semiconductor power device.
    Type: Grant
    Filed: April 1, 2014
    Date of Patent: February 14, 2017
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Ji Pang, Daniel Ng, Anup Bhalla, Xiaobin Wang
  • Publication number: 20170018627
    Abstract: A vertical JFET made by a process using a limited number of masks. A first mask is used to form mesas and trenches in active cell and termination regions simultaneously. A maskless self-aligned process is used to form silicide source and gate contacts. A second mask is used to open windows to the contacts. A third mask is used to pattern overlay metallization. An optional fourth mask is used to pattern passivation. Optionally the channel may be doped via angled implantation, and the width of the trenches and mesas in the active cell region may be varied from those in the termination region.
    Type: Application
    Filed: September 15, 2016
    Publication date: January 19, 2017
    Inventors: Zhongda Li, Anup Bhalla
  • Publication number: 20170018657
    Abstract: A vertical JFET made by a process using a limited number of masks. A first mask is used to form mesas and trenches in active cell and termination regions simultaneously. A mask-less self-aligned process is used to form silicide source and gate contacts. A second mask is used to open windows to the contacts. A third mask is used to pattern overlay metallization. An optional fourth mask is used to pattern passivation. Optionally the channel may be doped via angled implantation, and the width of the trenches and mesas in the active cell region may be varied from those in the termination region.
    Type: Application
    Filed: July 14, 2015
    Publication date: January 19, 2017
    Inventors: Zhongda Li, Anup Bhalla
  • Patent number: 9543413
    Abstract: A corner layout for a semiconductor device that maximizes the breakdown voltage is disclosed. The device includes first and second subsets of the striped cell arrays. The ends of each striped cell in the first array is spaced a uniform distance from the nearest termination device structure. In the second subset, the ends of striped cells proximate a corner of the active cell region are configured to maximize breakdown voltage by spacing the ends of each striped cell a non-uniform distance from the nearest termination device structure. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
    Type: Grant
    Filed: December 28, 2015
    Date of Patent: January 10, 2017
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR INCORPORATED
    Inventors: Lingpeng Guan, Anup Bhalla
  • Publication number: 20170005183
    Abstract: The present invention concerns a monolithically merged trenched-and-implanted Bipolar Junction Transistor (TI-BJT) with antiparallel diode and a method of manufacturing the same. Trenches are made in a collector, base, emitter stack downto the collector. The base electrode is formed on an implanted base contact region at the bottom surface of the trench. The present invention also provides for products produced by the methods of the present invention and for apparatuses used to perform the methods of the present invention.
    Type: Application
    Filed: February 10, 2015
    Publication date: January 5, 2017
    Applicant: United Silicon Carbide, Inc.
    Inventors: Anup BHALLA, Leonid FURSIN
  • Publication number: 20160380073
    Abstract: A heterostructure field effect transistor (HFET) gallium nitride (GaN) semiconductor power device comprises a hetero junction structure comprises a first semiconductor layer interfacing a second semiconductor layer of two different band gaps thus generating an interface layer as a two-dimensional electron gas (2DEG) layer. The power device further comprises a source electrode and a drain electrode disposed on two opposite sides of a gate electrode disposed on top of the hetero junction structure for controlling a current flow between the source and drain electrodes in the 2DEG layer.
    Type: Application
    Filed: June 3, 2015
    Publication date: December 29, 2016
    Inventors: Anup Bhalla, Tinggang Zhu
  • Publication number: 20160380117
    Abstract: Trench JFETs may be created by etching trenches into the topside of a substrate of a first doping type to form mesas. The substrate is made up of a backside drain layer, a middle drift layer, and topside source layer. The etching goes through the source layer and partly into the drift layer. Gate regions are formed on the sides and bottoms of the trenches using doping of a second type. Vertical channel regions are formed behind the vertical gate segments via angled implantation using a doping of the first kind, providing improved threshold voltage control. Optionally the substrate may include a lightly doped channel layer between the drift and source layers, such that the mesas include a lightly doped channel region that more strongly contrasts with the implanted vertical channel regions.
    Type: Application
    Filed: September 9, 2016
    Publication date: December 29, 2016
    Inventors: Anup Bhalla, Peter Alexandrov
  • Publication number: 20160372542
    Abstract: This invention discloses a semiconductor power device disposed in a semiconductor substrate comprising a heavily doped region formed on a lightly doped region and having an active cell area and an edge termination area. The edge termination area comprises a plurality of termination trenches formed in the heavily doped region with the termination trenches lined with a dielectric layer and filled with a conductive material therein. The edge termination further includes a plurality of buried guard rings formed as doped regions in the lightly doped region of the semiconductor substrate immediately adjacent to the termination trenches.
    Type: Application
    Filed: July 12, 2014
    Publication date: December 22, 2016
    Inventors: Yeeheng Lee, Madhur Bobde, Yongping Ding, Jongoh Kim, Anup Bhalla
  • Publication number: 20160372610
    Abstract: A termination structure for a nitride-based Schottky diode includes a guard ring formed by an epitaxially grown P-type nitride-based compound semiconductor layer and dielectric field plates formed on the guard ring. The termination structure is formed at the edge of the anode electrode of the Schottky diode and has the effect of reducing electric field crowding at the anode electrode edge, especially when the Schottky diode is reverse biased. In one embodiment, the P-type epitaxial layer includes a step recess to further enhance the field spreading effect of the termination structure.
    Type: Application
    Filed: June 22, 2016
    Publication date: December 22, 2016
    Inventors: TingGang Zhu, Anup Bhalla, Ping Huang, Yueh-Se Ho
  • Patent number: 9520480
    Abstract: A heterostructure field effect transistor (HFET) gallium nitride (GaN) semiconductor power device comprises a hetero junction structure comprises a first semiconductor layer interfacing a second semiconductor layer of two different band gaps thus generating an interface layer as a two-dimensional electron gas (2DEG) layer. The power device further comprises a source electrode and a drain electrode disposed on two opposite sides of a gate electrode disposed on top of the hetero junction structure for controlling a current flow between the source and drain electrodes in the 2DEG layer.
    Type: Grant
    Filed: June 3, 2015
    Date of Patent: December 13, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Anup Bhalla, Tinggang Zhu
  • Patent number: 9520464
    Abstract: This invention discloses a semiconductor power device disposed in a semiconductor substrate and having an active cell area and an edge termination area the edge termination area wherein the edge termination area comprises a superjunction structure having doped semiconductor columns of alternating conductivity types with a charge imbalance between the doped semiconductor columns to generate a saddle junction electric field in the edge termination.
    Type: Grant
    Filed: January 4, 2016
    Date of Patent: December 13, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Madhur Bobde, Lingpeng Guan, Anup Bhalla, Hamza Yilmaz
  • Publication number: 20160351659
    Abstract: A semiconductor device includes a semiconductor substrate and epitaxial layer of a first conductivity type with the epitaxial layer on a top surface of the substrate. A body region of a second conductivity type opposite the first conductivity type is disposed near a top surface of the epitaxial layer. A first conductivity type source region is inside the body region and a drain is at a bottom surface of the substrate. An inslated gate overlaps the source and body regions. First and second trenches in the epitaxial layer are lined with insulation material and filled with electrically conductive material. Second conductivity type buried regions are positioned below the trenches. Second conductivity type charge linking paths along one or more walls of the first trench electrically connect a first buried region to the body region. A second buried region is separated from the body region by portions of the expitaxial layer.
    Type: Application
    Filed: August 12, 2016
    Publication date: December 1, 2016
    Inventors: Anup Bhalla, Hamza Yilmaz, Madhur Bobde, Lingpeng Guan, Jun Hu, Jongoh Kim, Yongping Ding
  • Patent number: 9502503
    Abstract: Semiconductor devices includes a thin epitaxial layer (nanotube) formed on sidewalls of mesas formed in a semiconductor layer. In one embodiment, a semiconductor device includes a first epitaxial layer and a second epitaxial layer formed on mesas of the semiconductor layer. The thicknesses and doping concentrations of the first and second epitaxial layers and the mesa are selected to achieve charge balance in operation. In another embodiment, the semiconductor body is lightly doped and the thicknesses and doping concentrations of the first and second epitaxial layers are selected to achieve charge balance in operation.
    Type: Grant
    Filed: April 12, 2016
    Date of Patent: November 22, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Hamza Yilmaz, Xiaobin Wang, Anup Bhalla, John Chen, Hong Chang
  • Publication number: 20160336432
    Abstract: Trench JFETs may be created by etching trenches into the topside of a substrate of a first doping type to form mesas. The substrate is made up of a backside drain layer, a middle drift layer, and topside source layer. The etching goes through the source layer and partly into the drift layer. Gate regions are formed on the sides and bottoms of the trenches using doping of a second type. Vertical channel regions are formed behind the vertical gate segments via angled implantation using a doping of the first kind, providing improved threshold voltage control. Optionally the substrate may include a lightly doped channel layer between the drift and source layers, such that the mesas include a lightly doped channel region that more strongly contrasts with the implanted vertical channel regions.
    Type: Application
    Filed: July 28, 2016
    Publication date: November 17, 2016
    Inventors: Anup Bhalla, Peter Alexandrov
  • Publication number: 20160322469
    Abstract: This invention discloses a semiconductor power device. The trenched semiconductor power device includes a trenched gate, opened from a top surface of a semiconductor substrate, surrounded by a source region encompassed in a body region near the top surface above a drain region disposed on a bottom surface of a substrate. The semiconductor power device further includes an implanting-ion block disposed above the top surface on a mesa area next to the body region having a thickness substantially larger than 0.3 micron for blocking body implanting ions and source ions from entering into the substrate under the mesa area whereby masks for manufacturing the semiconductor power device can be reduced.
    Type: Application
    Filed: May 2, 2015
    Publication date: November 3, 2016
    Inventors: Anup Bhalla, François Hébert, Sung-Shan Tai, Sik K. Lui
  • Publication number: 20160322459
    Abstract: This invention discloses a semiconductor power device disposed in a semiconductor substrate and the semiconductor substrate has a plurality of trenches. Each of the trenches is filled with a plurality of epitaxial layers of alternating conductivity types constituting nano tubes functioning as conducting channels stacked as layers extending along a sidewall direction with a “Gap Filler” layer filling a merging-gap between the nano tubes disposed substantially at a center of each of the trenches. The “Gap Filler” layer can be very lightly doped Silicon or grown and deposited dielectric layer. In an exemplary embodiment, the plurality of trenches are separated by pillar columns each having a width approximately half to one-third of a width of the trenches.
    Type: Application
    Filed: May 1, 2015
    Publication date: November 3, 2016
    Inventors: Hamza Yilmaz, Daniel Ng, Lingping Guan, Anup Bhalla, Wilson Ma, Moses Ho, John Chen
  • Publication number: 20160315053
    Abstract: A semiconductor power device comprises a plurality of power transistor cells each having a trenched gate disposed in a gate trench wherein the trenched gate comprising a shielding bottom electrode disposed in a bottom portion of the gate trench electrically insulated from a top gate electrode disposed in a top portion of the gate trench by an inter-electrode insulation layer. At least one of the transistor cells includes the shielding bottom electrode functioning as a source-connecting shielding bottom electrode electrically connected to a source electrode of the semiconductor power device and at least one of the transistor cells having the shielding bottom electrode functioning as a gate-connecting shielding bottom electrode electrically connected to a gate metal of the semiconductor power device.
    Type: Application
    Filed: April 1, 2014
    Publication date: October 27, 2016
    Inventors: Ji Pan, Daniel Ng, Anup Bhalla, Xiaobin Wang
  • Patent number: 9478646
    Abstract: A method for fabricating an anode-shorted field stop insulated gate bipolar transistor (IGBT) comprises selectively forming first and second semiconductor implant regions of opposite conductivity types. A field stop layer of a second conductivity type can be grown onto or implanted into the substrate. An epitaxial layer can be grown on the substrate or on the field stop layer. One or more insulated gate bipolar transistors (IGBT) component cells are formed within the epitaxial layer.
    Type: Grant
    Filed: July 27, 2011
    Date of Patent: October 25, 2016
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR INCORPORATED
    Inventors: Anup Bhalla, Madhur Bobde, Yongping Ding, Xiaotian Zhang, Yueh-Se Ho