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: 20180308967
    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 27, 2018
    Publication date: October 25, 2018
    Inventors: Anup Bhalla, Tinggang Zhu
  • Patent number: 10103240
    Abstract: A lateral super junction JFET is formed from stacked alternating P type and N type semiconductor layers over a P-epi layer supported on an N+ substrate. An N+ drain column extends down through the super junction structure and the P-epi to connect to the N+ substrate to make the device a bottom drain device. N+ source column and P+ gate column extend through the super junction but stop at the P-epi layer. A gate-drain avalanche clamp diode is formed from the bottom the P+ gate column through the P-epi to the N+ drain substrate.
    Type: Grant
    Filed: February 10, 2013
    Date of Patent: October 16, 2018
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Madhur Bobde, Lingpeng Guann, Anup Bhalla, Hamza Yilmaz
  • Patent number: 10074742
    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: Grant
    Filed: December 7, 2015
    Date of Patent: September 11, 2018
    Assignee: Alpha and Omega Semiconductor Limited
    Inventors: Anup Bhalla, Xiaobin Wang, Ji Pan, Sung-Po Wei
  • Patent number: 10069005
    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: February 6, 2017
    Date of Patent: September 4, 2018
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Lingpeng Guan, Anup Bhalla, Hamza Yilmaz
  • Patent number: 10062755
    Abstract: Semiconductor devices are formed using a thin epitaxial layer (nanotube) formed on sidewalls of dielectric-filled trenches. In one embodiment, a termination structure is formed in the termination area and includes an array of termination cells formed in the termination area, the array of termination cells including a first termination cell at an interface to the active area to a last termination cell, each termination cell in the array of termination cells being formed in a mesa of the first semiconductor layer and having a first width; and an end termination cell being formed next to the last termination cell in the termination area, the end termination cell being formed in an end mesa of the first semiconductor layer and having a second width greater than the first width.
    Type: Grant
    Filed: January 10, 2018
    Date of Patent: August 28, 2018
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Hamza Yilmaz, Xiaobin Wang, Anup Bhalla, John Chen, Hong Chang
  • Publication number: 20180240872
    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: August 23, 2018
    Inventors: Hamza Yilmaz, Daniel Ng, Lingping Guan, Anup Bhalla, Wilson Ma, Moses Ho, John Chen
  • Patent number: 10056500
    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: Grant
    Filed: September 15, 2016
    Date of Patent: August 21, 2018
    Assignee: United Silicon Carbide, Inc.
    Inventors: Zhongda Li, Anup Bhalla
  • Patent number: 10050134
    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: June 8, 2016
    Date of Patent: August 14, 2018
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR INCORPORATED
    Inventors: Anup Bhalla, Madhur Bobde, Yongping Ding, Xiaotian Zhang, Yueh-Se Ho
  • Patent number: 10050154
    Abstract: A vertical JFET with a ladder termination may be made by a method 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: Grant
    Filed: January 13, 2017
    Date of Patent: August 14, 2018
    Assignee: United Silicon Carbide, Inc.
    Inventors: Zhongda Li, Anup Bhalla
  • Publication number: 20180226513
    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: April 6, 2018
    Publication date: August 9, 2018
    Inventors: Zhongda Li, Anup Bhalla
  • Patent number: 10038106
    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: Grant
    Filed: June 29, 2017
    Date of Patent: July 31, 2018
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: TingGang Zhu, Anup Bhalla, Ping Huang, Yueh-Se Ho
  • Publication number: 20180212022
    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: January 23, 2018
    Publication date: July 26, 2018
    Inventors: Lingpeng Guan, Anup Bhalla, Madhur Bobde, Tinggang Zhu
  • Patent number: 10032584
    Abstract: This invention discloses a power switch that includes a fast-switch semiconductor power device and a slow-switch semiconductor power device controllable to turn on and off a current transmitting therethrough. The slow-switch semiconductor power device further includes a ballasting resistor for increasing a device robustness of the slow switch semiconductor power device. In an exemplary embodiment, the fast-switch semiconductor power device includes a fast switch metal oxide semiconductor field effect transistor (MOSFET) and the slow-switch semiconductor power device includes a slow switch MOSFET wherein the slow switch MOSFET further includes a source ballasting resistor.
    Type: Grant
    Filed: December 30, 2014
    Date of Patent: July 24, 2018
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Sik K. Lui, Anup Bhalla
  • Publication number: 20180204937
    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: Application
    Filed: March 9, 2018
    Publication date: July 19, 2018
    Inventors: Anup Bhalla, Madhur Bobde, Yongping Ding, Xiaotian Zhang, Yueh-Se Ho
  • Patent number: 10020389
    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: November 30, 2016
    Date of Patent: July 10, 2018
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Anup Bhalla, Tinggang Zhu
  • Patent number: 9978740
    Abstract: A unidirectional transient voltage suppressor (TVS) device is formed with first and second NPN transistors that are connected in parallel to each other. Each NPN transistor includes a collector region, an emitter. The first and second NPN structures are formed on a common substrate. The first NPN transistor has a floating base and the second NPN transistor has a base shorted to an emitter.
    Type: Grant
    Filed: June 17, 2016
    Date of Patent: May 22, 2018
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Lingpeng Guan, Madhur Bobde, Anup Bhalla
  • Publication number: 20180138906
    Abstract: This invention discloses a power switch that includes a fast-switch semiconductor power device and a slow-switch semiconductor power device controllable to turn on and off a current transmitting therethrough. The slow-switch semiconductor power device further includes a ballasting resistor for increasing a device robustness of the slow switch semiconductor power device. In an exemplary embodiment, the fast-switch semiconductor power device includes a fast switch metal oxide semiconductor field effect transistor (MOSFET) and the slow-switch semiconductor power device includes a slow switch MOSFET wherein the slow switch MOSFET further includes a source ballasting resistor.
    Type: Application
    Filed: December 30, 2014
    Publication date: May 17, 2018
    Inventors: Sik K. Lui, Anup Bhalla
  • Publication number: 20180130880
    Abstract: Semiconductor devices are formed using a thin epitaxial layer (nanotube) formed on sidewalls of dielectric-filled trenches. In one embodiment, a termination structure is formed in the termination area and includes an array of termination cells formed in the termination area, the array of termination cells including a first termination cell at an interface to the active area to a last termination cell, each termination cell in the array of termination cells being formed in a mesa of the first semiconductor layer and having a first width; and an end termination cell being formed next to the last termination cell in the termination area, the end termination cell being formed in an end mesa of the first semiconductor layer and having a second width greater than the first width.
    Type: Application
    Filed: January 10, 2018
    Publication date: May 10, 2018
    Inventors: Hamza Yilmaz, Xiaobin Wang, Anup Bhalla, John Chen, Hong Chang
  • Patent number: 9960237
    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: Grant
    Filed: April 13, 2015
    Date of Patent: May 1, 2018
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Xiaobin Wang, Anup Bhalla, Hamza Yilmaz, Daniel Ng
  • Publication number: 20180102435
    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: December 8, 2017
    Publication date: April 12, 2018
    Inventors: François Hébert, Madjur Bobde, Anup Bhalla