Patents Assigned to Alpha and Omega Semiconductor Incorporated
  • 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
  • Patent number: 9627526
    Abstract: A semiconductor device having a plurality of transistors includes a termination area that features a transistor with an asymmetric gate.
    Type: Grant
    Filed: March 24, 2014
    Date of Patent: April 18, 2017
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Yeeheng Lee, Yongping Ding, Xiaobin Wang
  • Patent number: 9620614
    Abstract: This invention discloses a semiconductor power device formed in a semiconductor substrate includes rows of multiple horizontal columns of thin layers of alternate conductivity types in a drift region of the semiconductor substrate where each of the thin layers having a thickness to enable a punch through the thin layers when the semiconductor power device is turned on. In a specific embodiment the thickness of the thin layers satisfying charge balance equation q*ND*WN=q*NA*WP and a punch through condition of WP<2*WD*[ND/(NA+ND)] where ND and WN represent the doping concentration and the thickness of the N type layers 160, while NA and WP represent the doping concentration and thickness of the P type layers; WD represents the depletion width; and q represents an electron charge, which cancel out. This device allows for a near ideal rectangular electric field profile at breakdown voltage with sawtooth like ridges.
    Type: Grant
    Filed: September 25, 2013
    Date of Patent: April 11, 2017
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Madhur Bobde
  • Patent number: 9620630
    Abstract: Semiconductor power devices can be formed on substrate structure having a lightly doped semiconductor substrate of a first conductivity type or a second conductivity type opposite to the first conductivity type. A semiconductive first buffer layer of the first conductivity type formed above the substrate. A doping concentration of the first buffer layer is greater than a doping concentration of the substrate. A second buffer layer of the second conductivity type formed above the first buffer layer. An epitaxial layer of the second conductivity type formed above the second buffer layer. One or more heavily doped regions of the second conductivity type are formed through portions of the first buffer layer from the second buffer layer and into corresponding portions of the substrate. This abstract is provided with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
    Type: Grant
    Filed: March 16, 2016
    Date of Patent: April 11, 2017
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR INCORPORATED
    Inventors: Madhur Bobde, Jun Hu, Lingpeng Guan, Hamza Yilmaz, Lei Zhang, Jongoh Kim
  • 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: 20170098626
    Abstract: The present invention discloses small-size battery protection packages and provides a process of fabricating small-size battery protection packages. A battery protection package includes a first common-drain metal oxide semiconductor field effect transistor (MOSFET), a second common-drain MOSFET, a power control integrated circuit (IC), a plurality of solder balls, a plurality of conductive bumps, and a packaging layer. The power control IC is vertically stacked on top of the first and second common-drain MOSFETs. At least a majority portion of the power control IC and at least majority portions of the plurality of solder balls are embedded into the packaging layer.
    Type: Application
    Filed: December 21, 2016
    Publication date: April 6, 2017
    Applicant: Alpha and Omega Semiconductor Incorporated
    Inventors: Zhiqiang Niu, Yan Xun Xue, Man Sheng Hu, Jun Lu, Yueh-Se Ho, Hamza Yilmaz
  • Publication number: 20170093281
    Abstract: The invention proposes a system and method for extending the maximum duty cycle of a step-down switching converter to nearly 100% while maintaining a constant switching frequency. The system includes a voltage mode or current mode step-down converter driven by a leading edge blanking (LEB) signal, which operates at the desired switching frequency. More particularly, the LEB signal is connected to a slope generator and/or a current sense network. In each switching cycle, the LEB signal forces the slope signal and/or current sense signal to reset, thereby achieving a constant switching frequency. Corresponding methods for how to extend the maximum duty cycle of a step-down switching converter while maintaining a constant frequency are also disclosed.
    Type: Application
    Filed: September 24, 2015
    Publication date: March 30, 2017
    Applicant: Alpha and Omega Semiconductor Incorporated
    Inventor: Youngbok KIM
  • Patent number: 9595609
    Abstract: A semiconductor device includes a superjunction structure formed using simultaneous N and P angled implants into the sidewall of a trench. The simultaneous N and P angled implants use different implant energies and dopants of different diffusion rate so that after annealing, alternating N and P thin semiconductor regions are formed. The alternating N and P thin semiconductor regions form a superjunction structure where a balanced space charge region is formed to enhance the breakdown voltage characteristic of the semiconductor device.
    Type: Grant
    Filed: September 21, 2015
    Date of Patent: March 14, 2017
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Karthik Padmanabhan, Madhur Bobde, Lingpeng Guan, Lei Zhang, Hamza Yilmaz
  • Patent number: 9595517
    Abstract: A semiconductor device includes a semiconductor layer of a first conductivity type formed on a substrate; a first trench formed in the semiconductor layer including a first trench gate; a second trench formed in the semiconductor layer and extending into the substrate and including a second trench gate; a first transistor device formed in the semiconductor layer adjacent the first trench. The second trench encircles active area of the first transistor device to provide electrical isolation of the first transistor device.
    Type: Grant
    Filed: October 12, 2015
    Date of Patent: March 14, 2017
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Shekar Mallikarjunaswamy
  • Patent number: 9595587
    Abstract: Embodiments of the present disclosure provide a contact structure in a split-gate trench transistor device for electrically connecting the top electrode to the bottom electrode inside the trench. The transistor device comprises a semiconductor substrate and one or more trenches formed in the semiconductor substrate. The trenches are lined with insulating materials along the sidewalls inside the trenches. Each trench has a bottom electrode in lower portions of the trench and a top electrode in its upper portions. The bottom electrode and the top electrode are separated by an insulating material. A contact structure filled with conductive materials is formed in each trench in an area outside of an active region of the device to connect the top electrode and the bottom electrode. It is emphasized that 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.
    Type: Grant
    Filed: April 23, 2014
    Date of Patent: March 14, 2017
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Yeeheng Lee, Sik Lui, Jongoh Kim, Hong Chang, Madhur Bobde, Lingpeng Guan, Hamza Yilmaz
  • Publication number: 20170069750
    Abstract: A semiconductor device having a plurality of transistors includes a termination area that features a transistor with an asymmetric gate.
    Type: Application
    Filed: March 24, 2014
    Publication date: March 9, 2017
    Applicant: ALPHA & OMEGA SEMICONDUCTOR INCORPORATED
    Inventors: Yeeheng Lee, Yongping Ding, Xiaobin Wang
  • Patent number: 9583586
    Abstract: A low capacitance transient voltage suppressor with snapback control and a reduced voltage punch-through breakdown mode 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. A set of source regions is formed within a top surface of the second epitaxial layer. Implant regions are formed in the second epitaxial layer, with a first implant region located below the first source region.
    Type: Grant
    Filed: December 22, 2015
    Date of Patent: February 28, 2017
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR INCORPORATED
    Inventors: Ning Shi, Lingpeng Guan, Madhur Bobde
  • 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
  • Patent number: 9564516
    Abstract: A MOSFET device and fabrication method are disclosed. The MOSFET has a drain in chip plane with an epitaxial layer overlay atop. The MOSFET further comprises: a Kelvin-contact body and an embedded Kelvin-contact source; a trench gate extending into the epitaxial layer; a lower contact trench extending through the Kelvin-contact source and at least part of the Kelvin-contact body defining respectively a vertical source-contact surface and a vertical body-contact surface; a patterned dielectric layer atop the Kelvin-contact source and the trench gate; a patterned top metal layer. As a result: a planar ledge is formed atop the Kelvin-contact source; the MOSFET device exhibits a lowered body Kelvin contact impedance and, owing to the presence of the planar ledge, a source Kelvin contact impedance that is lower than an otherwise MOSFET device without the planar ledge; and an integral parallel Schottky diode is also formed.
    Type: Grant
    Filed: January 22, 2015
    Date of Patent: February 7, 2017
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Ji Pan
  • Patent number: 9564406
    Abstract: The present invention discloses small-size battery protection packages and provides a process of fabricating small-size battery protection packages. A battery protection package includes a first common-drain metal oxide semiconductor field effect transistor (MOSFET), a second common-drain MOSFET, a power control integrated circuit (IC), a plurality of solder balls, a plurality of conductive bumps, and a packaging layer. The power control IC is vertically stacked on top of the first and second common-drain MOSFETs. At least a majority portion of the power control IC and at least majority portions of the plurality of solder balls are embedded into the packaging layer.
    Type: Grant
    Filed: July 30, 2015
    Date of Patent: February 7, 2017
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR INCORPORATED
    Inventors: Zhiqiang Niu, Yan Xun Xue, Man Sheng Hu, Jun Lu, Yueh-Se Ho, Hamza Yilmaz
  • Publication number: 20170033060
    Abstract: The present invention discloses small-size battery protection packages and provides a process of fabricating small-size battery protection packages. A battery protection package includes a first common-drain metal oxide semiconductor field effect transistor (MOSFET), a second common-drain MOSFET, a power control integrated circuit (IC), a plurality of solder balls, a plurality of conductive bumps, and a packaging layer. The power control IC is vertically stacked on top of the first and second common-drain MOSFETs. At least a majority portion of the power control IC and at least majority portions of the plurality of solder balls are embedded into the packaging layer.
    Type: Application
    Filed: July 30, 2015
    Publication date: February 2, 2017
    Applicant: ALPHA AND OMEGA SEMICONDUCTOR INCORPORATED
    Inventors: Zhiqiang Niu, Yan Xun Xue, Man Sheng Hu, Jun Lu, Yueh-Se Ho, Hamza Yilmaz
  • Patent number: 9559179
    Abstract: A semiconductor device formed on a semiconductor substrate having a substrate top surface, comprising: a gate trench extending from the substrate top surface into the semiconductor substrate; a gate electrode in the gate trench; a gate top dielectric material disposed over the gate electrode; a body region adjacent to the gate trench; a source region embedded in the body region; a metal layer disposed over at least a portion of a gate trench opening and at least a portion of the source region, wherein: the source region has a curved sidewall portion that is adjacent to the gate trench, and that extends above the gate top dielectric material.
    Type: Grant
    Filed: September 30, 2015
    Date of Patent: January 31, 2017
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: John Chen
  • Publication number: 20170025356
    Abstract: A method to provide a wafer level package with increasing contact pad area comprising the steps of forming a first packaging layer on wafer top surface, grinding the wafer back surface and etch through holes, depositing a metal to fill the through holes and covering wafer backside, cutting through the wafer from wafer backside forming a plurality of grooves separating each chip then depositing a second packaging layer filling the grooves and covering the wafer back metal, reducing the first packaging layer thickness to expose the second packaging layer filling the grooves and forming a plurality of contact pads overlaying the first packaging layer thereafter cutting through the second packaging layer in the grooves to form individual package.
    Type: Application
    Filed: October 6, 2016
    Publication date: January 26, 2017
    Applicant: Alpha and Omega Semiconductor Incorporated
    Inventor: Yan Xun Xue