Patents by Inventor Sik K. Lui

Sik K. Lui 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: 20140225187
    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: Application
    Filed: February 9, 2013
    Publication date: August 14, 2014
    Inventors: Anup Bhalla, François Hébert, Sung-Shan Tai, Sik K. Lui
  • Publication number: 20140085760
    Abstract: A protection circuit for a power transistor includes a first transistor connected in parallel with the power transistor and having a control terminal connected to a first power supply voltage through a first resistive element; and a first set of diodes connected between a first terminal and a control terminal of the first transistor. In operation, the voltage at the first terminal of the first transistor is clamped to a clamp voltage and the first transistor is turned on to conduct current in a forward conduction mode when an over-voltage condition occurs at a first terminal of the power transistor.
    Type: Application
    Filed: September 27, 2012
    Publication date: March 27, 2014
    Applicant: ALPHA & OMEGA SEMICONDUCTOR, INC.
    Inventor: Sik K. Lui
  • Patent number: 8643135
    Abstract: This invention discloses a semiconductor power device disposed in a semiconductor substrate and having an active cell area and an edge termination area wherein the edge termination area comprises a wide trench filled with a field-crowding reduction filler and a buried field plate buried under a top surface of the semiconductor substrate and laterally extended over a top portion of the field crowding field to move a peak electric field laterally away from the active cell area. In a specific embodiment, the field-crowding reduction filler comprises a silicon oxide filled in the wide trench.
    Type: Grant
    Filed: May 31, 2011
    Date of Patent: February 4, 2014
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Madhur Bobde, Sik K Lui, Anup Bhalla
  • 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
  • Patent number: 8445370
    Abstract: A method for manufacturing a Schottky diode comprising steps of 1) providing a region with a dopant of a second conductivity type opposite to a first conductivity type to form a top doped region in a semiconductor substrate of said first conductivity type; 2) providing a trench through the top doped region to a predetermined depth and providing a dopant of the second conductivity type to form a bottom dopant region of the second conductivity type; and 3) lining a Schottky barrier metal layer on a sidewall of the trench at least extending from a bottom of the top doped region to a top of the bottom doped region.
    Type: Grant
    Filed: June 14, 2010
    Date of Patent: May 21, 2013
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Sik K Lui, Anup Bhalla
  • Patent number: 8431989
    Abstract: This invention discloses a semiconductor power device that includes a plurality of power transistor cells surrounded by a trench opened in a semiconductor substrate. At least one of the cells constituting an active cell has a source region disposed next to a trenched gate electrically connecting to a gate pad and surrounding the cell. The trenched gate further has a bottom-shielding electrode filled with a gate material disposed below and insulated from the trenched gate. At least one of the cells constituting a source-contacting cell surrounded by the trench with a portion functioning as a source connecting trench is filled with the gate material for electrically connecting between the bottom-shielding electrode and a source metal disposed directly on top of the source connecting trench.
    Type: Grant
    Filed: April 28, 2011
    Date of Patent: April 30, 2013
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Anup Bhalla, Sik K. Lui
  • Publication number: 20130093001
    Abstract: This invention discloses a new switching device that includes a drain disposed on a first surface and a source region disposed near a second surface of a semiconductor opposite the first surface. An insulated gate electrode is disposed on top of the second surface for controlling a source to drain current and a source electrode is interposed into the insulated gate electrode for substantially preventing a coupling of an electrical field between the gate electrode and an epitaxial region underneath the insulated gate electrode. The source electrode further covers and extends over the insulated gate for covering an area on the second surface of the semiconductor to contact the source region, An epitaxial layer is disposed above and having a different dopant concentration than the drain region. The gate electrode is insulated from the source electrode by an insulation layer having a thickness depending on a Vgsmax rating of the vertical power device.
    Type: Application
    Filed: March 30, 2012
    Publication date: April 18, 2013
    Inventors: Anup Bhalla, Daniel Ng, Tiesheng Li, Sik K. Lui
  • Patent number: 8372708
    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: October 4, 2011
    Date of Patent: February 12, 2013
    Inventors: Anup Bhalla, François Hébert, Sung-Shan Tai, Sik K Lui
  • Patent number: 8357973
    Abstract: This invention discloses bottom-source lateral diffusion MOS (BS-LDMOS) device. The device has a source region disposed laterally opposite a drain region near a top surface of a semiconductor substrate supporting a gate thereon between the source region and a drain region. The BS-LDMOS device further has a combined sinker-channel region disposed at a depth in the semiconductor substrate entirely below a body region disposed adjacent to the source region near the top surface wherein the combined sinker-channel region functioning as a buried source-body contact for electrically connecting the body region and the source region to a bottom of the substrate functioning as a source electrode. A drift region is disposed near the top surface under the gate and at a distance away from the source region and extending to and encompassing the drain region.
    Type: Grant
    Filed: August 25, 2011
    Date of Patent: January 22, 2013
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Sik K Lui, François Hébert, Anup Bhalla
  • Publication number: 20120306044
    Abstract: This invention discloses a semiconductor power device disposed in a semiconductor substrate and having an active cell area and an edge termination area wherein the edge termination area comprises a wide trench filled with a field-crowding reduction filler and a buried field plate buried under a top surface of the semiconductor substrate and laterally extended over a top portion of the field crowding field to move a peak electric field laterally away from the active cell area. In a specific embodiment, the field-crowding reduction filler comprises a silicon oxide filled in the wide trench.
    Type: Application
    Filed: May 31, 2011
    Publication date: December 6, 2012
    Inventors: Madhur Bobde, Sik K. Lui, Anup Bhalla
  • 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: 8174283
    Abstract: This invention discloses a method for calibrating a gate resistance measurement of a semiconductor power device that includes a step of forming a RC network on a test area on a semiconductor wafer adjacent to a plurality of semiconductor power chips and measuring a resistance and a capacitance of the RC network to prepare for carrying out a wafer-level measurement calibration of the semiconductor power device. The method further includes a step of connecting a probe card to a set of contact pads on the semiconductor wafer for carrying out the wafer-level measurement calibration followed by performing a gate resistance Rg measurement for the semiconductor power chips.
    Type: Grant
    Filed: May 11, 2009
    Date of Patent: May 8, 2012
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Anup Bhalla, Sik K. Lui, Daniel Ng
  • Patent number: 8169062
    Abstract: A semiconductor integrated circuit package having a leadframe (108) that includes a leadframe pad (103a) disposed under a die (100) and a bonding metal area (101a) that is disposed over at least two adjacent sides of the die. The increase in the bonding metal area (101a) increases the number of interconnections between the metal area (101a) and the die (100) to reduce the electric resistance and inductance. Furthermore, the surface area of the external terminals radiating from the package's plastic body (106) is increased if not maximized so that heat can be dissipated quicker and external terminal resistances reduced. The integrated circuit is applicable for MOSFET devices and the bonding metal area (101a) is used for the source terminal (101). The bonding metal area may have a “L” shape, a “C” shape, a “J” shape, an “I” shape or any combination thereof.
    Type: Grant
    Filed: May 24, 2011
    Date of Patent: May 1, 2012
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Leeshawn Luo, Anup Bhalla, Yueh-Se Ho, Sik K. Lui, Mike Chang
  • Patent number: 8163618
    Abstract: This invention discloses a new switching device supported on a semiconductor that includes a drain disposed on a first surface and a source region disposed near a second surface of said semiconductor opposite the first surface. The switching device further includes an insulated gate electrode disposed on top of the second surface for controlling a source to drain current. The switching device further includes a source electrode interposed into the insulated gate electrode for substantially preventing a coupling of an electrical field between the gate electrode and an epitaxial region underneath the insulated gate electrode. The source electrode further covers and extends over the insulated gate for covering an area on the second surface of the semiconductor to contact the source region. The semiconductor substrate further includes an epitaxial layer disposed above and having a different dopant concentration than the drain region.
    Type: Grant
    Filed: February 9, 2010
    Date of Patent: April 24, 2012
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Anup Bhalla, Daniel Ng, Tiesheng Li, Sik K. Lui
  • Patent number: 8119482
    Abstract: This invention discloses a new MOSFET device. The MOSFET device has an improved operation characteristic achieved by manufacturing a MOSFET with a higher gate work function by implementing a P-doped gate in an N-MOSFET device. The P-type gate increases the threshold voltage and shifts the C-Vds characteristics. The reduced Cgd thus achieves the purpose of suppressing the shoot through and resolve the difficulties discussed above. Unlike the conventional techniques, the reduction of the capacitance Cgd is achieved without requiring complicated fabrication processes and control of the recess electrode.
    Type: Grant
    Filed: December 23, 2010
    Date of Patent: February 21, 2012
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Anup Bhalla, Sik K. Lui
  • Publication number: 20120025301
    Abstract: This invention discloses bottom-source lateral diffusion MOS (BS-LDMOS) device. The device has a source region disposed laterally opposite a drain region near a top surface of a semiconductor substrate supporting a gate thereon between the source region and a drain region. The BS-LDMOS device further has a combined sinker-channel region disposed at a depth in the semiconductor substrate entirely below a body region disposed adjacent to the source region near the top surface wherein the combined sinker-channel region functioning as a buried source-body contact for electrically connecting the body region and the source region to a bottom of the substrate functioning as a source electrode. A drift region is disposed near the top surface under the gate and at a distance away from the source region and extending to and encompassing the drain region.
    Type: Application
    Filed: August 25, 2011
    Publication date: February 2, 2012
    Inventors: Sik K. Lui, François Hébert, Anup Bhalla
  • Publication number: 20120018793
    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: Application
    Filed: October 4, 2011
    Publication date: January 26, 2012
    Inventors: Anup Bhalla, François Hébert, Sung-Shan Tai, Sik K. Lui
  • Publication number: 20120007206
    Abstract: This invention discloses bottom-anode Schottky (BAS) device supported on a semiconductor substrate having a bottom surface functioning as an anode electrode with an epitaxial layer has a same doped conductivity as said anode electrode overlying the anode electrode. The BAS device further includes an Schottky contact metal disposed in a plurality of trenches and covering a top surface of the semiconductor substrate between the trenches. The BAS device further includes a plurality of doped JBS regions disposed on sidewalls and below a bottom surface of the trenches doped with an opposite conductivity type from the anode electrode constituting a junction barrier Schottky (JBS) with the epitaxial layer disposed between the plurality of doped JBS regions. The BAS device further includes an ultra-shallow Shannon implant layer disposed immediate below the Schottky contact metal in the epitaxial layer between the plurality of doped JBS regions.
    Type: Application
    Filed: August 23, 2011
    Publication date: January 12, 2012
    Inventors: Anup Bhalla, Sik K. Lui, Yi Su
  • Patent number: 8067822
    Abstract: A semiconductor integrated circuit package having a leadframe (108) that includes a leadframe pad (103a) disposed under a die (100) and a bonding metal area (101a) that is disposed over at least two adjacent sides of the die. The increase in the bonding metal area (101a) increases the number of interconnections between the metal area (101a) and the die (100) to reduce the electric resistance and inductance. Furthermore, the surface area of the external terminals radiating from the package's plastic body (106) is increased if not maximized so that heat can be dissipated quicker and external terminal resistances reduced. The integrated circuit is applicable for MOSFET devices and the bonding metal area (101a) is used for the source terminal (101). The bonding metal area may have a “L” shape, a “C” shape, a “J” shape, an “I” shape or any combination thereof.
    Type: Grant
    Filed: June 23, 2008
    Date of Patent: November 29, 2011
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Leeshawn Luo, Anup Bhalla, Yueh-Se Ho, Sik K. Lui, Mike Chang
  • Patent number: 8035159
    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: April 30, 2007
    Date of Patent: October 11, 2011
    Assignee: Alpha & Omega Semiconductor, Ltd.
    Inventors: Anup Bhalla, François Hébert, Sung-Shan Tai, Sik K Lui