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: 20170213908
    Abstract: Disclosed herein is a shielded-gate silicon carbide trench MOS-controlled switch, such as a MOSFET or IGBT, with a reduced Miller capacitance. The switch disclosed herein can be used in a variety of applications, including high temperature and/or high voltage power conversion.
    Type: Application
    Filed: July 1, 2015
    Publication date: July 27, 2017
    Inventors: Leonid FURSIN, Anup BHALLA
  • Publication number: 20170213887
    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: April 5, 2017
    Publication date: July 27, 2017
    Inventors: Lingpeng Guan, Anup Bhalla, Madhur Bobde, Tinggang Zhu
  • Patent number: 9716156
    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: Grant
    Filed: May 2, 2015
    Date of Patent: July 25, 2017
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Anup Bhalla, François Hébert, Sung-Shan Tai, Sik K Lui
  • Patent number: 9716057
    Abstract: A composite semiconductor device, such as a high-voltage cascode, is constructed in a single package by mounting a first die on a first planar substrate and second die mounted on a second planar substrate, where the substrates are separated by a gap filled with a dielectric encapsulant. The substrates may be separated both vertically and as well as laterally, to lie in different parallel planes. The substrates are in a leadframe that also includes interconnections, heat sinks, package pins, and removable tie-bars, forming a contiguous metallic structure. Multi-device frames containing multiple leadframes joined by additional tie-bars may be used to process multiple composite semiconductor devices together in, e.g., step-and-repeat wire and die bonding processes and batch encapsulation molding batch processes.
    Type: Grant
    Filed: August 24, 2016
    Date of Patent: July 25, 2017
    Assignee: United Silicon Carbide, Inc.
    Inventors: Hao Zhang, Anup Bhalla
  • Patent number: 9704955
    Abstract: Semiconductor devices are formed using a thin epitaxial layer (nanotube) formed on sidewalls of dielectric-filled trenches. In one embodiment, a method for forming a semiconductor device includes forming a first epitaxial layer on sidewalls of trenches and forming second epitaxial layer on the first epitaxial layer where charges in the doped regions along the sidewalls of the first and second trenches achieve charge balance in operation. In another embodiment, the semiconductor device includes a termination structure including an array of termination cells.
    Type: Grant
    Filed: October 19, 2016
    Date of Patent: July 11, 2017
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Hamza Yilmaz, Xiaobin Wang, Anup Bhalla, John Chen, Hong Chang
  • Patent number: 9685523
    Abstract: This invention discloses a semiconductor device disposed in a semiconductor substrate. The semiconductor device includes a first semiconductor layer of a first conductivity type on a first major surface. The semiconductor device further includes a second semiconductor layer of a second conductivity type on a second major surface opposite the first major surface. The semiconductor device further includes an injection efficiency controlling buffer layer of a first conductivity type disposed immediately below the second semiconductor layer to control the injection efficiency of the second semiconductor layer.
    Type: Grant
    Filed: December 17, 2014
    Date of Patent: June 20, 2017
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Madhur Bobde, Harsh Naik, Lingpeng Guan, Anup Bhalla, Sik Lui
  • Publication number: 20170148910
    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: Application
    Filed: February 6, 2017
    Publication date: May 25, 2017
    Applicant: Alpha and Omega Semiconductor Incorporated
    Inventors: Lingpeng Guan, Anup Bhalla, Hamza Yilmaz
  • Patent number: 9653618
    Abstract: A JFET is formed with vertical and horizontal elements made from a high band-gap semiconductor material such as silicon carbide via triple implantation of a substrate comprising an upper drift region and a lower drain region, the triple implantation forming a lower gate, a horizontal channel, and an upper gate, in a portion of the drift region. A source region may be formed through a portion of the top gate, and the top and bottom gates are connected. A vertical channel region is formed adjacent to the planar JFET region and extending through the top gate, horizontal channel, and bottom gate to connect to the drift, such that the lower gate modulates the vertical channel as well as the horizontal channel, and current from the sources flows first through the horizontal channel and then through the vertical channel into the drift.
    Type: Grant
    Filed: October 21, 2015
    Date of Patent: May 16, 2017
    Assignee: United Silicon Carbide, Inc.
    Inventors: Anup Bhalla, Zhongda Li
  • Publication number: 20170133518
    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: Application
    Filed: January 13, 2017
    Publication date: May 11, 2017
    Inventors: Zhongda Li, Anup Bhalla
  • Patent number: 9647059
    Abstract: This invention discloses a method for manufacturing a semiconductor power device on a semiconductor substrate supporting a drift region composed of an epitaxial layer. The method includes a first step of growing a first epitaxial layer followed by forming a first hard mask layer on top of the epitaxial layer; a second step of applying a first implant mask to open a plurality of implant windows and applying a second implant mask for blocking some of the implant windows to implant a plurality of dopant regions of alternating conductivity types adjacent to each other in the first epitaxial layer; and a third step of repeating the first step and the second step by applying the same first and second implant masks to form a plurality of epitaxial layers, each of which is implanted with the dopant regions of the alternating conductivity types.
    Type: Grant
    Filed: June 8, 2014
    Date of Patent: May 9, 2017
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Lingping Guan, Madhur Bobde, Anup Bhalla, Yeeheng Lee, John Chen, Moses Ho
  • Publication number: 20170125514
    Abstract: This invention discloses a method for manufacturing a semiconductor power device on a semiconductor substrate supporting a . drift region composed of an epitaxial layer. The method includes a first step of growing a first epitaxial layer followed by forming a first hard mask layer on top of the epitaxial layer; a second step of applying a first implant mask to open a plurality of implant windows and applying a second implant mask for blocking some of the implant windows to implant a plurality of dopant regions of alternating conductivity types adjacent to each other in the first epitaxial layer; and a third step of repeating the first step and the second step by applying the same first and second implant masks to form a plurality of epitaxial layers, each of which is implanted with the dopant regions of the alternating conductivity types.
    Type: Application
    Filed: June 8, 2014
    Publication date: May 4, 2017
    Inventors: Lingpeng Guan, Madhur Bobde, Anup Bhalla, Yeeheng Lee, John Chen, Moses Ho
  • Publication number: 20170125394
    Abstract: A silicon surge bypass diode is co-packaged with a high bandgap junction barrier Schottky diode. The co-packaged diodes may be used in a power circuits such as power factor correction circuits, converters, inverters circuit, motor drives, and protection circuits, for example. The high bandgap diode may be made of silicon carbide, gallium nitride, aluminum nitride, aluminum gallium nitride, and/or diamond, for example. The high bandgap diode may be formed by diode connecting a transistor, such as a high-electron-mobility transistor (HEMT). The high bandgap diode may be much smaller than the silicon diode. The package may have a common terminal for the diode cathodes, and separate terminals for the anodes of each diode.
    Type: Application
    Filed: October 25, 2016
    Publication date: May 4, 2017
    Inventor: Anup Bhalla
  • Publication number: 20170117418
    Abstract: A JFET is formed with vertical and horizontal elements made from a high band-gap semiconductor material such as silicon carbide via triple implantation of a substrate comprising an upper drift region and a lower drain region, the triple implantation forming a lower gate, a horizontal channel, and an upper gate, in a portion of the drift region. A source region may be formed through a portion of the top gate, and the top and bottom gates are connected. A vertical channel region is formed adjacent to the planar JFET region and extending through the top gate, horizontal channel, and bottom gate to connect to the drift, such that the lower gate modulates the vertical channel as well as the horizontal channel, and current from the sources flows first through the horizontal channel and then through the vertical channel into the drift.
    Type: Application
    Filed: October 21, 2015
    Publication date: April 27, 2017
    Inventors: Anup Bhalla, Zhongda Li
  • Publication number: 20170117392
    Abstract: A JFET is formed with vertical and horizontal elements made from a high band-gap semiconductor material such as silicon carbide via triple implantation of a substrate comprising an upper drift region and a lower drain region, the triple implantation forming a lower gate, a horizontal channel, and an upper gate, in a portion of the drift region. A source region may be formed through a portion of the top gate, and the top and bottom gates are connected. A vertical channel region is formed adjacent to the planar JFET region and extending through the top gate, horizontal channel, and bottom gate to connect to the drift, such that the lower gate modulates the vertical channel as well as the horizontal channel, and current from the sources flows first through the horizontal channel and then through the vertical channel into the drift.
    Type: Application
    Filed: September 16, 2016
    Publication date: April 27, 2017
    Inventors: Anup Bhalla, Zhongda Li
  • Publication number: 20170117386
    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: Application
    Filed: February 10, 2013
    Publication date: April 27, 2017
    Inventors: Madhur Bobde, Lingpeng Guan, Anup Bhalla, Hamza Yilmaz
  • Patent number: 9620584
    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 7, 2014
    Date of Patent: April 11, 2017
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Lingpeng Guan, Anup Bhalla, Madhur Bobde, Tinggang Zhu
  • Patent number: 9620498
    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: Grant
    Filed: July 26, 2014
    Date of Patent: April 11, 2017
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Yi Su, Anup Bhalla, Daniel Ng
  • Publication number: 20170084730
    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: November 30, 2016
    Publication date: March 23, 2017
    Inventors: Anups Bhalla, Tinggang Zhu
  • Publication number: 20170084694
    Abstract: Semiconductor devices are formed using a thin epitaxial layer (nanotube) formed on sidewalls of dielectric-filled trenches. In one embodiment, a method for forming a semiconductor device includes forming a first epitaxial layer on sidewalls of trenches and forming second epitaxial layer on the first epitaxial layer where charges in the doped regions along the sidewalls of the first and second trenches achieve charge balance in operation. In another embodiment, the semiconductor device includes a termination structure including an array of termination cells.
    Type: Application
    Filed: October 19, 2016
    Publication date: March 23, 2017
    Inventors: Hamza Yilmaz, Xiaobin Wang, Anup Bhalla, John Chen, Hong Chang
  • Publication number: 20170069740
    Abstract: This invention discloses an insulated gate bipolar transistor (IGBT) device formed in a semiconductor substrate. The IGBT device has a split-shielded trench gate that includes an upper gate segment and a lower shield segment. The IGBT device may further include a dummy trench filled with a dielectric layer disposed at a distance away from the split-shielded trench gate. The IGBT device further includes a body region extended between the split-shielded trench gate and the dummy trench encompassing a source region surrounding the split-shielded trench gate near a top surface of the semiconductor substrate. The IGBT device further includes a heavily doped N region disposed below the body region and above a source-dopant drift region above a bottom body-dopant collector region at a bottom surface of the semiconductor substrate. In an alternative embodiment, the IGBT may include a planar gate with a trench shield electrode.
    Type: Application
    Filed: May 11, 2013
    Publication date: March 9, 2017
    Inventors: Madhur Bobde, Anup Bhalla