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).

  • Patent number: 8884406
    Abstract: A semiconductor device wafer includes a test structure. The test structure includes a layer of material having an angle-shaped test portion disposed on at least a portion of a surface of the semiconductor wafer. A ruler marking on the surface of the semiconductor wafer proximate the test portion is adapted to facilitate measurement of a change in length of the test portion.
    Type: Grant
    Filed: September 13, 2011
    Date of Patent: November 11, 2014
    Assignee: Alpha & Omega Semiconductor Ltd
    Inventors: Yingying Lou, Tiesheng Li, Yu Wang, Anup Bhalla
  • Patent number: 8878292
    Abstract: This invention discloses a semiconductor power device disposed in a semiconductor substrate. The semiconductor power device includes trenched gates each having a stick-up gate segment extended above a top surface of the semiconductor substrate surrounded by sidewall spacers. The semiconductor power device further includes slots opened aligned with the sidewall spacers substantially parallel to the trenched gates. The stick-up gate segment further includes a cap composed of an insulation material surrounded by the sidewall spacers. A layer of barrier metal covers a top surface of the cap and over the sidewall spacers and extends above a top surface of the slots. The slots are filled with a gate material same as the gate segment for functioning as additional gate electrodes for providing a depletion layer extends toward the trenched gates whereby a drift region between the slots and the trenched gate is fully depleted at a gate-to-drain voltage Vgs=0 volt.
    Type: Grant
    Filed: March 2, 2008
    Date of Patent: November 4, 2014
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: François Hébert, Madhur Bobde, Anup Bhalla
  • Publication number: 20140319606
    Abstract: This invention discloses a semiconductor power device that includes a plurality of power transistor cells surrounded by a trench opened in a semiconductor substrate. At least one of the cells constituting an active cell has a source region disposed next to a trenched gate electrically connecting to a gate pad and surrounding the cell. The trenched gate further has a bottom-shielding electrode filled with a gate material disposed below and insulated from the trenched gate. At least one of the cells constituting a source-contacting cell surrounded by the trench with a portion functioning as a source connecting trench is filled with the gate material for electrically connecting between the bottom-shielding electrode and a source metal disposed directly on top of the source connecting trench.
    Type: Application
    Filed: April 26, 2013
    Publication date: October 30, 2014
    Inventors: Anup Bhalla, Sik K. Lui
  • Publication number: 20140319604
    Abstract: A semiconductor power device formed in a semiconductor substrate comprising a highly doped region near a top surface of the semiconductor substrate on top of a lightly doped region supported by a heavily doped region. The semiconductor power device further comprises source trenches opened into the highly doped region filled with conductive trench filling material in electrical contact with the source region near the top surface. The semiconductor power device further comprises buried P-regions disposed below the source trenches and doped with dopants of opposite conductivity from the highly doped region. 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: Application
    Filed: July 11, 2014
    Publication date: October 30, 2014
    Inventors: Anup Bhalla, Hamza Yilmaz, Madhur Bobde, Lingpeng Guan, Jun Hu, Jongoh Kim, Yongping Ding
  • Publication number: 20140319605
    Abstract: A semiconductor power device may include a lightly doped layer formed on a heavily doped layer. One or more devices are formed in the lightly doped layer. Each device may include a body region, a source region, and one or more gate electrodes formed in corresponding trenches in the lightly doped region. Each of the trenches has a depth in a first dimension, a width in a second dimension and a length in a third dimension. The body region is of opposite conductivity type to the lightly and heavily doped layers. The source region is formed proximate the upper surface. One or more deep contacts are formed at one or more locations along the third dimension proximate one or more of the trenches. The contacts extend in the first direction from the upper surface into the lightly doped layer and are in electrical contact with the source region.
    Type: Application
    Filed: July 11, 2014
    Publication date: October 30, 2014
    Inventors: Hamza Yilmaz, Daniel Ng, Daniel Calafut, Madhur Bobde, Anup Bhalla, Ji Pan, Yeeheng Lee, Jongoh Kim
  • Patent number: 8866267
    Abstract: A semiconductor device with substrate-side exposed device-side electrode (SEDE) is disclosed. The semiconductor device has semiconductor substrate (SCS) with device-side, substrate-side and semiconductor device region (SDR) at device-side. Device-side electrodes (DSE) are formed for device operation. A through substrate trench (TST) is extended through SCS, reaching a DSE turning it into an SEDE. The SEDE can be interconnected via conductive interconnector through TST. A substrate-side electrode (SSE) and a windowed substrate-side passivation (SSPV) atop SSE can be included. The SSPV defines an area of SSE for spreading solder material during device packaging. A device-side passivation (DSPV) beneath thus covering the device-side of SEDE can be included. A DSE can also include an extended support ledge, stacked below an SEDE, for structurally supporting it during post-wafer processing packaging.
    Type: Grant
    Filed: May 28, 2010
    Date of Patent: October 21, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Tao Feng, Anup Bhalla
  • Patent number: 8860098
    Abstract: The present disclosure describes structures and processes to produce high voltage JFETs in wide-bandgap materials, most particularly in Silicon Carbide. The present disclosure also provides for products produced by the methods of the present disclosure and for apparatuses used to perform the methods of the present disclosure.
    Type: Grant
    Filed: March 14, 2014
    Date of Patent: October 14, 2014
    Assignee: United Silicon Carbide, Inc.
    Inventors: Anup Bhalla, Peter Alexandrov
  • Publication number: 20140299914
    Abstract: Semiconductor devices are formed using a thin epitaxial layer (nanotube) formed on sidewalls of dielectric-filled trenches. In one embodiment, a semiconductor device is formed in a second semiconductor layer disposed on a first semiconductor layer of opposite conductivity type and having trenches formed therein where the trenches extend from the top surface to the bottom surface of the second semiconductor layer. The semiconductor device includes a first epitaxial layer formed on sidewalls of the trenches where the first epitaxial layer is substantially charge balanced with adjacent semiconductor regions. The semiconductor device further includes a first dielectric layer formed in the trenches adjacent the first epitaxial layer and a gate electrode disposed in an upper portion of at least some of the trenches above the first dielectric layer and insulated from the sidewalls of the trenches by a gate dielectric layer.
    Type: Application
    Filed: April 2, 2014
    Publication date: October 9, 2014
    Applicant: Alpha and Omega Semiconductor Incorporated
    Inventors: Hamza Yilmaz, Xiaobin Wang, Anup Bhalla, John Chen, Hong Chang
  • Patent number: 8847306
    Abstract: A semiconductor substrate may be etched to form trenches with three different widths. A first conductive material is formed at the bottom of the trenches. A second conductive material separated by an insulator is formed over the first conductive material. A first insulator layer is formed on the trenches. A body layer is formed in the substrate. A source is formed in the body layer. A second insulator layer is formed on the trenches and source. Source and gate contacts are formed through the second insulator layer. Source and gate metal are formed on the second insulator layer. 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. 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: January 4, 2012
    Date of Patent: September 30, 2014
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Sung-Shan Tai, Hamza Yilmaz, Anup Bhalla, Hong Chang, John Chen
  • Publication number: 20140273417
    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: May 28, 2014
    Publication date: September 18, 2014
    Applicant: ALPHA AND OMEGA SEMICONDUCTOR INCORPORATED
    Inventors: TingGang Zhu, Anup Bhalla, Madhur Bobde
  • Publication number: 20140264571
    Abstract: A trench formed in a body layer and epitaxial layer of a substrate is lined with a dielectric layer. A shield electrode formed within a lower portion of the trench is insulated by the dielectric layer. A gate electrode formed in the trench above the shield electrode is insulated from the shield electrode by another dielectric layer. One or more source regions formed within the body layer is adjacent a sidewall of the trench. A source pad formed above the body layer is electrically connected to the source regions and insulated from the gate electrode and shield electrode. The source pad provides an external contact to the source region. A gate pad provides an external contact to the gate electrode. A shield electrode pad provides an external contact to the shield electrode. A resistive element is electrically connected between the shield electrode pad and a source lead.
    Type: Application
    Filed: June 3, 2014
    Publication date: September 18, 2014
    Applicant: Alpha and Omega Semiconductor Incorporated
    Inventors: Sik Lui, Yi Su, Daniel Ng, Daniel Calafut, Anup Bhalla
  • Publication number: 20140264477
    Abstract: The present disclosure describes structures and processes to produce high voltage JFETs in wide-bandgap materials, most particularly in Silicon Carbide. The present disclosure also provides for products produced by the methods of the present disclosure and for apparatuses used to perform the methods of the present disclosure.
    Type: Application
    Filed: March 14, 2014
    Publication date: September 18, 2014
    Applicant: United Silicon Carbide, Inc.
    Inventors: Anup Bhalla, Peter Alexandrov
  • Patent number: 8836015
    Abstract: A semiconductor power device is supported on a semiconductor substrate with a bottom layer functioning as a bottom electrode and an epitaxial layer overlying the bottom layer as the bottom layer. The semiconductor power device includes a plurality of FET cells and each cell further includes a body region extending from a top surface into the epitaxial layer. The body region encompasses a heavy body dopant region. An insulated gate is disposed on the top surface of the epitaxial layer, overlapping a first portion of the body region. A barrier control layer is disposed on the top surface of the epitaxial layer next to the body region away from the insulated gate. A conductive layer overlies the top surface of the epitaxial layer covering a second portion of the body region and the heavy body dopant region extending over the barrier control layer forming a Schottky junction diode.
    Type: Grant
    Filed: January 31, 2012
    Date of Patent: September 16, 2014
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Anup Bhalla
  • Patent number: 8835977
    Abstract: A transient-voltage suppressing (TVS) device disposed on a semiconductor substrate of a first conductivity type. The TVS includes a buried dopant region of a second conductivity type disposed and encompassed in an epitaxial layer of the first conductivity type wherein the buried dopant region extends laterally and has an extended bottom junction area interfacing with the underlying portion of the epitaxial layer thus constituting a Zener diode for the TVS device. The TVS device further includes a region above the buried dopant region further comprising a top dopant layer of a second conductivity type and a top contact region of a second conductivity type which act in combination with the epitaxial layer and the buried dopant region to form a plurality of interfacing PN junctions constituting a SCR acting as a steering diode to function with the Zener diode for suppressing a transient voltage.
    Type: Grant
    Filed: December 19, 2012
    Date of Patent: September 16, 2014
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Madhur Bobde, Lingpeng Guan, Anup Bhalla, Limin Weng
  • Publication number: 20140252372
    Abstract: A vertical conduction nitride-based Schottky diode is formed using an insulating substrate which was lifted off after the diode device is encapsulated on the front side with a wafer level molding compound. The wafer level molding compound provides structural support on the front side of the diode device to allow the insulating substrate to be lifted off so that a conductive layer can be formed on the backside of the diode device as the cathode electrode. A vertical conduction nitride-based Schottky diode is thus realized. In another embodiment, a protection circuit for a vertical GaN Schottky diode employs a silicon-based vertical PN junction diode connected in parallel to the GaN Schottky diode to divert reverse bias avalanche current.
    Type: Application
    Filed: May 15, 2014
    Publication date: September 11, 2014
    Applicant: Alpha and Omega Semiconductor Incorporated
    Inventors: TingGang Zhu, Anup Bhalla, Ping Huang, Yueh-Se Ho
  • Patent number: 8829614
    Abstract: This invention discloses a method for manufacturing a semiconductor power device in a semiconductor substrate comprises an active cell area and a termination area.
    Type: Grant
    Filed: August 31, 2009
    Date of Patent: September 9, 2014
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Lingpeng Guan, Anup Bhalla, Madhur Bobde, Tinggang Zhu
  • Patent number: 8828857
    Abstract: An integrated structure combines field effect transistors and a Schottky diode. Trenches formed into a substrate composition extend along a depth of the substrate composition forming mesas therebetween. Each trench is filled with conductive material separated from the trench walls by dielectric material forming a gate region. Two first conductivity type body regions inside each mesa form wells partly into the depth of the substrate composition. An exposed portion of the substrate composition separates the body regions. Second conductivity type source regions inside each body region are adjacent to and on opposite sides of each well. Schottky barrier metal inside each well forms Schottky junctions at interfaces with exposed vertical sidewalls of the exposed portion of the substrate composition separating the body regions.
    Type: Grant
    Filed: April 29, 2013
    Date of Patent: September 9, 2014
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Sik Lui, Yi Su, Daniel Ng, Anup Bhalla
  • Patent number: 8829603
    Abstract: A shielded gate trench field effect transistor can be formed on a substrate having an epitaxial layer on the substrate and a body layer on the epitaxial layer. A trench formed in the body layer and epitaxial layer is lined with a dielectric layer. A shield electrode is formed within a lower portion of the trench. The shield electrode is insulated by the dielectric layer. A gate electrode is formed in the trench above the shield electrode and insulated from the shield electrode by an additional dielectric layer. One or more source regions formed within the body layer is adjacent a sidewall of the trench. A source pad formed above the body layer is electrically connected to the one or more source regions and insulated from the gate electrode and shield electrode. The source pad provides an external contact to the source region. A gate pad provides an external contact to the gate electrode. A shield electrode pad provides an external contact to the shield electrode.
    Type: Grant
    Filed: August 18, 2011
    Date of Patent: September 9, 2014
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Sik Lui, Yi Su, Daniel Ng, Daniel Calafut, Anup Bhalla
  • Patent number: 8829640
    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: March 29, 2011
    Date of Patent: September 9, 2014
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Madhur Bobde, Lingpeng Guan, Anup Bhalla, Hamza Yilmaz
  • Patent number: 8822300
    Abstract: A low capacitance transient voltage suppressor with reduced clamping voltage includes an n+ type substrate, a first epitaxial layer on the substrate, a buried layer formed within the first epitaxial layer, a second epitaxial layer on the first epitaxial layer, and an implant layer formed within the first epitaxial layer below the buried layer. The implant layer extends beyond the buried layer. A first trench is at an edge of the buried layer and an edge of the implant layer. A second trench is at another edge of the buried layer and extends into the implant layer. A third trench is at another edge of the implant layer. Each trench is lined with a dielectric layer. A set of source regions is formed within a top surface of the second epitaxial layer. The trenches and source regions alternate. A pair of implant regions is formed in the second epitaxial layer.
    Type: Grant
    Filed: January 16, 2014
    Date of Patent: September 2, 2014
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Lingpeng Guan, Madhur Bobde, Anup Bhalla, Jun Hu, Wayne F. Eng