Patents Assigned to Alpha and Omega Semiconductor Limited
  • Patent number: 10535764
    Abstract: Fabricating a semiconductor device includes: forming a first gate trench and a second gate trench in an epitaxial layer overlaying a semiconductor substrate; depositing gate material in the first gate trench to form a first gate and depositing gate material in the second gate trench to form a second gate; forming a body; forming a source; forming an active region contact trench that extends through the source and the body, and a gate contact trench within the second gate; forming an island region under the active region contact trench and disconnected from the body, the island region having an opposite polarity as the epitaxial layer; and disposing a first electrode within the active region contact trench and a second electrode within the gate contact trench.
    Type: Grant
    Filed: July 31, 2018
    Date of Patent: January 14, 2020
    Assignee: Alpha and Omega Semiconductor Limited
    Inventors: Anup Bhalla, Xiaobin Wang, Ji Pan, Sung-Po Wei
  • 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: 9236450
    Abstract: Fabricating a semiconductor device includes: forming a gate trench in an epitaxial layer overlaying a semiconductor substrate; depositing gate material in the gate trench; forming a body; forming a source; forming an active region contact trench that extends through the source and the body into a drain; forming a Schottky barrier controlling layer in the epitaxial layer in bottom region of the active region contact trench; and disposing a contact electrode within the active region contact trench. The Schottky barrier controlling layer controls Schottky barrier height of a Schottky diode formed by the contact electrode and the drain.
    Type: Grant
    Filed: June 10, 2014
    Date of Patent: January 12, 2016
    Assignee: Alpha and Omega Semiconductor Limited
    Inventors: Anup Bhalla, Xiaobin Wang, Ji Pan, Sung-Po Wei
  • Patent number: 8928079
    Abstract: A semiconductor device is formed on a semiconductor substrate. The device includes: a drain; an epitaxial layer overlaying the drain, wherein a drain region extends into the epitaxial layer; and an active region. The active region includes: a body disposed in the epitaxial layer, having a body top surface; a source embedded in the body, extending from the body top surface into 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 into the body; and an active region contact electrode disposed within the active region contact trench. A layer of body region separates the active region contact electrode from the epitaxial layer, and a low injection diode is formed below a body/drain junction.
    Type: Grant
    Filed: September 11, 2012
    Date of Patent: January 6, 2015
    Assignee: Alpha and Omega Semiconductor Limited
    Inventors: Anup Bhalla, Xiaobin Wang, Ji Pan, Sung-Po Wei
  • Patent number: 8809143
    Abstract: Fabricating a semiconductor device includes: forming a gate trench in an epitaxial layer overlaying a semiconductor substrate; depositing gate material in the gate trench; forming a body; forming a source; forming an active region contact trench that extends through the source and the body into the drain; forming a Schottky barrier controlling layer in the epitaxial layer in bottom region of the active region contact trench; and disposing a contact electrode within the active region contact trench.
    Type: Grant
    Filed: December 21, 2012
    Date of Patent: August 19, 2014
    Assignee: Alpha & Omega Semiconductor Limited
    Inventors: Anup Bhalla, Xiaobin Wang, Ji Pan, Sung-Po Wei
  • Patent number: 8728890
    Abstract: Fabricating a semiconductor device includes: forming a gate trench in an epitaxial layer overlaying a semiconductor substrate; depositing gate material in the gate trench; forming a body in the epitaxial layer, having a body top surface and a body bottom surface; forming a source; forming an active region contact trench that extends through the source and the body into the drain, wherein bottom surface of the active region contact trench is formed to include at least a portion that is shallower than the body bottom surface; and disposing a contact electrode within the active region contact trench.
    Type: Grant
    Filed: April 25, 2013
    Date of Patent: May 20, 2014
    Assignee: Alpha & Omega Semiconductor Limited
    Inventors: Anup Bhalla, Xiaobin Wang, Ji Pan, Sung-Po Wei
  • Patent number: 8597998
    Abstract: Fabricating a semiconductor device includes forming a mask on a substrate having a top substrate surface; forming a gate trench in the substrate, through the mask; depositing gate material in the gate trench; removing the mask to leave a gate structure; implanting a body region; implanting a source region; forming a source body contact trench having a trench wall and a trench bottom; forming a plug in the source body contact trench, wherein the plug extends below a bottom of the body region; and disposing conductive material in the source body contact trench, on top of the plug.
    Type: Grant
    Filed: September 5, 2012
    Date of Patent: December 3, 2013
    Assignee: Alpha & Omega Semiconductor Limited
    Inventors: Anup Bhalla, Sik K. Lui, Tiesheng Li
  • Publication number: 20130203225
    Abstract: Fabricating a semiconductor device includes: forming a gate trench in an epitaxial layer overlaying a semiconductor substrate; depositing gate material in the gate trench; forming a body; forming a source; forming an active region contact trench that extends through the source and the body into the drain; forming a Schottky barrier controlling layer in the epitaxial layer in bottom region of the active region contact trench; and disposing a contact electrode within the active region contact trench.
    Type: Application
    Filed: December 21, 2012
    Publication date: August 8, 2013
    Applicant: ALPHA & OMEGA SEMICONDUCTOR LIMITED
    Inventor: Alpha & Omega Semiconductor Limited
  • Patent number: 8450794
    Abstract: A semiconductor device is formed on a semiconductor substrate. The device comprises a drain; an epitaxial layer overlaying the drain; a body disposed in the epitaxial layer, having a body top surface and a body bottom surface; a source embedded in the body, extending from the body top surface into the body; a first gate trench extending into the epitaxial layer; a first gate disposed in the first gate trench; an active region contact trench extending through the source and at least part of the body into the drain; an active region contact electrode disposed within the active region contact trench; a second gate trench extending into the epitaxial layer; a second gate disposed in the gate trench; a gate contact trench formed within the second gate; and a gate contact electrode disposed within the gate contact trench.
    Type: Grant
    Filed: December 9, 2011
    Date of Patent: May 28, 2013
    Assignee: Alpha & Omega Semiconductor Limited
    Inventors: Anup Bhalla, Xiaobin Wang, Ji Pan, Sung-Po Wei
  • Patent number: 8362547
    Abstract: A semiconductor device formed on a semiconductor substrate includes: 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; and an active region. The active region includes: a body disposed in the epitaxial layer, having a body top surface; a source embedded in the body, extending from the body top surface into 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 into the drain region; an active region contact electrode disposed within the active region contact trench, wherein the active region contact electrode and the drain region form a Schottky diode; and a Schottky barrier controlling layer.
    Type: Grant
    Filed: December 21, 2007
    Date of Patent: January 29, 2013
    Assignee: Alpha & Omega Semiconductor Limited
    Inventors: Anup Bhalla, Xiaobin Wang, Ji Pan, Sung-Po Wei
  • Publication number: 20130009242
    Abstract: A semiconductor device is formed on a semiconductor substrate. The device includes: a drain; an epitaxial layer overlaying the drain, wherein a drain region extends into the epitaxial layer; and an active region. The active region includes: a body disposed in the epitaxial layer, having a body top surface; a source embedded in the body, extending from the body top surface into 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 into the body; and an active region contact electrode disposed within the active region contact trench. A layer of body region separates the active region contact electrode from the epitaxial layer, and a low injection diode is formed below a body/drain junction.
    Type: Application
    Filed: September 11, 2012
    Publication date: January 10, 2013
    Applicant: ALPHA & OMEGA SEMICONDUCTOR LIMITED
    Inventors: Anup Bhalla, Xiaobin Wang, Ji Pan, Sung-Po Wei
  • Publication number: 20120329225
    Abstract: Fabricating a semiconductor device includes forming a mask on a substrate having a top substrate surface; forming a gate trench in the substrate, through the mask; depositing gate material in the gate trench; removing the mask to leave a gate structure; implanting a body region; implanting a source region; forming a source body contact trench having a trench wall and a trench bottom; forming a plug in the source body contact trench, wherein the plug extends below a bottom of the body region; and disposing conductive material in the source body contact trench, on top of the plug.
    Type: Application
    Filed: September 5, 2012
    Publication date: December 27, 2012
    Applicant: ALPHA & OMEGA SEMICONDUCTOR LIMITED
    Inventors: Anup Bhalla, Sik Lui, Tiesheng Li
  • Patent number: 8288229
    Abstract: Fabricating a semiconductor device includes forming a hard mask on the substrate having a top substrate surface; forming a gate trench in the substrate, through the hard mask; depositing gate material in the gate trench; removing the hard mask to leave a gate structure; implanting a body region; implanting a source region; forming a source body contact trench having a trench wall and a trench bottom; and disposing an anti-punch through implant along at least a section of the trench wall but not along the trench bottom.
    Type: Grant
    Filed: March 9, 2011
    Date of Patent: October 16, 2012
    Assignee: Alpha & Omega Semiconductor Limited
    Inventors: Anup Bhalla, Sik K. Lui, Tiesheng Li
  • Patent number: 8283723
    Abstract: A semiconductor device is formed on a semiconductor substrate. The device includes a drain, an epitaxial layer overlaying the drain, and an active region. The active region includes a body disposed in the epitaxial layer, having a body top surface, a source embedded in the body, extending from the body top surface into 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 into the body, an active region contact electrode disposed within the active region contact trench, wherein a thin layer of body region separating the active region contact electrode from the drain.
    Type: Grant
    Filed: December 21, 2007
    Date of Patent: October 9, 2012
    Assignee: Alpha & Omega Semiconductor Limited
    Inventors: Anup Bhalla, Xiaobin Wang, Ji Pan, Sung-Po Wei
  • Publication number: 20120080751
    Abstract: A semiconductor device is formed on a semiconductor substrate. The device comprises a drain; an epitaxial layer overlaying the drain; a body disposed in the epitaxial layer, having a body top surface and a body bottom surface; a source embedded in the body, extending from the body top surface into the body; a first gate trench extending into the epitaxial layer; a first gate disposed in the first gate trench; an active region contact trench extending through the source and at least part of the body into the drain; an active region contact electrode disposed within the active region contact trench; a second gate trench extending into the epitaxial layer; a second gate disposed in the gate trench; a gate contact trench formed within the second gate; and a gate contact electrode disposed within the gate contact trench.
    Type: Application
    Filed: December 9, 2011
    Publication date: April 5, 2012
    Applicant: ALPHA & OMEGA SEMICONDUCTOR LIMITED
    Inventors: Anup Bhalla, Xiaobin Wang, Ji Pan, Sung-Po Wei
  • Patent number: 8093651
    Abstract: A semiconductor device is formed on a semiconductor substrate. The device comprises a drain, an epitaxial layer overlaying the drain, and an active region. The active region comprises a body disposed in the epitaxial layer, having a body top surface and a body bottom surface, a source embedded in the body, extending from the body top surface into 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 at least part of the body into the drain, wherein the active region contact trench is shallower than the body bottom surface, and an active region contact electrode disposed within the active region contact trench.
    Type: Grant
    Filed: December 21, 2007
    Date of Patent: January 10, 2012
    Assignee: Alpha & Omega Semiconductor Limited
    Inventors: Anup Bhalla, Xiaobin Wang, Ji Pan, Sung-Po Wei
  • Patent number: 8008151
    Abstract: A method of fabricating a semiconductor device comprises forming a hard mask on a substrate having a top substrate surface, forming a trench in the substrate, through the hard mask, depositing gate material in the trench, where the amount of gate material deposited in the trench extends beyond the top substrate surface, and removing the hard mask to leave a gate structure that extends substantially above the top substrate surface.
    Type: Grant
    Filed: November 9, 2007
    Date of Patent: August 30, 2011
    Assignee: Alpha and Omega Semiconductor Limited
    Inventors: Sung-Shan Tai, Tiesheng Li, Anup Bhalla, Hong Chang, Moses Ho
  • Publication number: 20110207276
    Abstract: Fabricating a semiconductor device includes forming a hard mask on the substrate having a top substrate surface; forming a gate trench in the substrate, through the hard mask; depositing gate material in the gate trench; removing the hard mask to leave a gate structure; implanting a body region; implanting a source region; forming a source body contact trench having a trench wall and a trench bottom; and disposing an anti-punch through implant along at least a section of the trench wall but not along the trench bottom.
    Type: Application
    Filed: March 9, 2011
    Publication date: August 25, 2011
    Applicant: ALPHA & OMEGA SEMICONDUCTOR LIMITED
    Inventors: Anup Bhalla, Sik K. Lui, Tiesheng Li
  • Patent number: 7923774
    Abstract: A semiconductor device includes a drain, a body disposed over the drain, a source embedded in the body, a gate trench extending through the source and the body into the drain, a gate disposed in the gate trench, a source body contact trench extending through the source into the body, a conductive contact layer disposed along at least a portion of a source body contact trench sidewall and in contact with at least a portion of the source, and a trench filling material disposed in the source body contact trench and overlaying at least a portion of the conductive contact layer.
    Type: Grant
    Filed: March 31, 2009
    Date of Patent: April 12, 2011
    Assignee: Alpha & Omega Semiconductor Limited
    Inventors: Anup Bhalla, Sik Lui, Tiesheng Li
  • Patent number: 7667264
    Abstract: A semiconductor device comprises a drain, a body in contact with the drain, the body having a body top surface, a source embedded in the body, extending downward from the body top surface into the body, a trench extending through the source and the body to the drain, and a gate disposed in the trench, having a gate top surface that extends substantially above the body top surface. A method of fabricating a semiconductor device comprises forming a hard mask on a substrate having a top substrate surface, forming a trench in the substrate, through the hard mask, depositing gate material in the trench, where the amount of gate material deposited in the trench extends beyond the top substrate surface, and removing the hard mask to leave a gate structure that extends substantially above the top substrate surface.
    Type: Grant
    Filed: September 27, 2004
    Date of Patent: February 23, 2010
    Assignee: Alpha and Omega Semiconductor Limited
    Inventors: Sung-Shan Tai, Tiesheng Li, Anup Bhalla, Hong Chang, Moses Ho