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: 9349796
    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: December 10, 2015
    Date of Patent: May 24, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Hamza Yilmaz, Xiaobin Wang, Anup Bhalla, John Chen, Hong Chang
  • Patent number: 9331068
    Abstract: A hybrid semiconductor bipolar switch in which a normally-on high-voltage wide-bandgap semiconductor bipolar switch and a normally-off field effect transistor are connected in a cascode (Baliga-pair) configuration. The switch may be constructed as a stacked hybrid device where a discrete transistor is bonded on top of a bipolar switch. Power systems may use plural switches paired with anti-parallel diodes.
    Type: Grant
    Filed: October 30, 2014
    Date of Patent: May 3, 2016
    Assignee: United Silicon Carbide, Inc.
    Inventors: Leonid Fursin, Anup Bhalla
  • Publication number: 20160118381
    Abstract: A hybrid semiconductor bipolar switch in which a normally-on high-voltage wide-bandgap semiconductor bipolar switch and a normally-off field effect transistor are connected in a cascode (Baliga-pair) configuration. The switch may be constructed as a stacked hybrid device where a discrete transistor is bonded on top of a bipolar switch. Power systems may use plural switches paired with anti-parallel diodes.
    Type: Application
    Filed: December 30, 2015
    Publication date: April 28, 2016
    Inventors: Leonid Fursin, Anup Bhalla
  • Publication number: 20160118459
    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: Application
    Filed: December 28, 2015
    Publication date: April 28, 2016
    Inventors: Lingpeng Guan, Anup Bhalla
  • Patent number: 9324807
    Abstract: A monolithically integrated MOS channel in gate-source shorted mode is used as a diode for the third quadrant conduction path for a power MOSFET. The MOS diode and MOSFET can be constructed in a variety of configurations including split-cell and trench. The devices may be formed of silicon carbide, gallium nitride, aluminum nitride, aluminum gallium nitride, diamond, or similar semiconductor. Low storage capacitance and low knee voltage for the MOS diode can be achieved by a variety of means. The MOS diode may be implemented with channel mobility enhancement materials, and/or have a very thin/high permittivity gate dielectric. The MOSFET gate conductor and MOS diode gate conductor may be made of polysilicon doped with opposite dopant types. The surface of the MOS diode dielectric may be implanted with cesium.
    Type: Grant
    Filed: July 10, 2015
    Date of Patent: April 26, 2016
    Assignee: United Silicon Carbide, Inc.
    Inventors: Anup Bhalla, Leonid Fursin
  • Patent number: 9324858
    Abstract: In a trench-gated MIS device contact is made to the gate within the trench, thereby eliminating the need to have the gate material, typically polysilicon, extend outside of the trench. This avoids the problem of stress at the upper corners of the trench. Contact between the gate metal and the polysilicon is normally made in a gate metal region that is outside the active region of the device. Various configurations for making the contact between the gate metal and the polysilicon are described, including embodiments wherein the trench is widened in the area of contact. Since the polysilicon is etched back below the top surface of the silicon throughout the device, there is normally no need for a polysilicon mask, thereby saving fabrication costs.
    Type: Grant
    Filed: November 1, 2010
    Date of Patent: April 26, 2016
    Assignee: Vishay-Siliconix
    Inventors: Anup Bhalla, Dorman Pitzer, Jacek Korec, Xiaorong Shi, Sik Lui
  • Patent number: 9318603
    Abstract: The invention relates to a power semiconductor device and its preparation methods thereof. Particularly, the invention aims at providing a method for reducing substrate contribution to the Rdson (drain-source on resistance) of power MOSFETs, and a power MOSFET device made by the method. By forming one or more bottom grooves at the bottom of Si substrate, the on resistance of the power MOSFET device attributed to the substrate is effectively reduced. A matching lead frame base complementary to the substrate with bottom grooves further improves the package of the power MOSFET device.
    Type: Grant
    Filed: March 8, 2014
    Date of Patent: April 19, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Yi Su, Daniel Ng, Anup Bhalla, Jun Lu
  • Patent number: 9312336
    Abstract: A semiconductor device includes a drain region, an epitaxial layer overlaying the drain region, and an active region. The active region includes: a body disposed in the epitaxial layer; a source embedded in the body; a gate trench extending into the epitaxial layer; a gate disposed in the gate trench; a contact trench extending through the source and at least part of the body; a contact electrode disposed in the contact trench; and an implant disposed at least in part along a contact trench wall; and an epitaxial enhancement portion disposed below the contact trench and in contact with the implant.
    Type: Grant
    Filed: October 18, 2013
    Date of Patent: April 12, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Ji Pan, Anup Bhalla
  • Publication number: 20160099315
    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: Application
    Filed: December 10, 2015
    Publication date: April 7, 2016
    Inventors: Hamza Yilmaz, Xiaobin Wang, Anup Bhalla, John Chen, Hong Chang
  • Publication number: 20160099308
    Abstract: An oxide termination semiconductor device may comprise a plurality of gate trenches, a gate runner, and an insulator termination trench. The gate trenches are located in an active region. Each gate trench includes a conductive gate electrode. The insulator termination trench is located in a termination region that surrounds the active region. The insulator termination trench is filled with an insulator material to form an insulator termination for the semiconductor device.
    Type: Application
    Filed: December 10, 2015
    Publication date: April 7, 2016
    Inventors: Sik Lui, Anup Bhalla
  • Publication number: 20160099351
    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: Application
    Filed: October 6, 2014
    Publication date: April 7, 2016
    Inventors: François Hébert, Madhur Bobde, Anup Bhalla
  • Publication number: 20160087093
    Abstract: A semiconductor device formed on a semiconductor substrate, comprising: an epitaxial layer overlaying the semiconductor substrate; a drain formed on back of the semiconductor substrate; a drain region that extends into the epitaxial layer; an active region; and an island region under the contact trench and disconnected from the body, the island region having an opposite polarity as the epitaxial layer. The active region comprises: a body disposed in the epitaxial layer; a source embedded in the body; a gate trench extending into the epitaxial layer; a gate disposed in the gate trench; an active region contact trench extending through the source and the body; and an active region contact electrode disposed within the active region contact trench.
    Type: Application
    Filed: December 7, 2015
    Publication date: March 24, 2016
    Inventors: Anup Bhalla, Xiaobin Wang, Ji Pan, Sung-Po Wei
  • Publication number: 20160079414
    Abstract: A semiconductor device includes a gate electrode, a top source region disposed next to the gate electrode, a drain region disposed below the bottom of the gate electrode, a dielectric disposed on top of the gate electrode, and a doped polysilicon spacer disposed on the source region and along a sidewall of the dielectric. Methods for manufacturing such device are also disclosed. 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: November 12, 2015
    Publication date: March 17, 2016
    Inventors: François Hébert, Anup Bhalla
  • Patent number: 9281394
    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: Grant
    Filed: July 11, 2014
    Date of Patent: March 8, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Hamza Yilmaz, Daniel Ng, Daniel Calafut, Madhur Bobde, Anup Bhalla, Ji Pan, Yeeheng Lee, Jongoh Kim
  • Publication number: 20160049392
    Abstract: A semiconductor power device is supported on a semiconductor substrate of a first conductivity type with a bottom layer functioning as a bottom electrode and an epitaxial layer overlying the bottom layer with a same conductivity type as the bottom layer. The semiconductor power device includes a plurality of FET cells and each cell further includes a body region of a second conductivity type extending from a top surface into the epitaxial layer. The body region encompasses a heavy body dopant region of second conductivity type. 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: Application
    Filed: August 13, 2014
    Publication date: February 18, 2016
    Inventor: Anup Bhalla
  • Publication number: 20160043169
    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: Application
    Filed: August 7, 2014
    Publication date: February 11, 2016
    Inventors: Lingpeng Guan, Anup Bhalla, Madhur Bobde, Tinggang Zhu
  • Patent number: 9257375
    Abstract: A multi-die package has a plurality of leads and first and second semiconductor dies in superimposition and bonded together defining a die stack. The die stack has opposed first and second sides, with each of the first and second semiconductor dies having gate, drain and source regions, and gate, drain and source contacts. The first opposed side has the drain contact of the second semiconductor die, which is in electrical communication with a first set of the plurality of leads. The gate, drain and source contacts of the first semiconductor die and the gate and source contacts of the second semiconductor die are disposed on the second of said opposed sides and in electrical communication with a second set of the plurality of leads. The lead for the source of the first semiconductor die may be the same as the lead for the drain of the second semiconductor die.
    Type: Grant
    Filed: September 20, 2011
    Date of Patent: February 9, 2016
    Assignee: Alpha and Omega Semiconductor Inc.
    Inventors: Anup Bhalla, Yi Su, David Grey
  • Publication number: 20160027771
    Abstract: A semiconductor power device supported on a semiconductor substrate comprising a plurality of transistor cells each having a source and a drain with a gate to control an electric current transmitted between the source and the drain. The semiconductor further includes a gate-to-drain (GD) clamp termination connected in series between the gate and the drain further includes a plurality of back-to-back polysilicon diodes connected in series to a silicon diode includes parallel doped columns in the semiconductor substrate wherein the parallel doped columns having a predefined gap. The doped columns further include a U-shaped bend column connect together the ends of parallel doped columns with a deep doped-well that is disposed below and engulfing the U-shaped bend.
    Type: Application
    Filed: July 26, 2014
    Publication date: January 28, 2016
    Inventors: Yi Su, Anup Bhalla, Daniel Ng
  • Patent number: 9245949
    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 semiconductor layer on a semiconductor substrate of opposite conductivity type and having trenches formed therein where the trenches extend from the top surface to the bottom surface of the 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. In another embodiment, a semiconductor device is formed in a first semiconductor layer having trenches and mesas formed thereon where the trenches extend from the top surface to the bottom surface of the first semiconductor layer. The semiconductor device includes semiconductor regions formed on the bottom surface of the mesas of the first semiconductor layer.
    Type: Grant
    Filed: December 4, 2014
    Date of Patent: January 26, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Hamza Yilmaz, Xiaobin Wang, Anup Bhalla, John Chen, Hong Chang
  • Publication number: 20160013267
    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: January 14, 2016
    Inventors: Yeeheng Lee, Madhur Bobde, Yongping Ding, Jongoh Kim, Anup Bhalla