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: 20110221005
    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 s 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: Application
    Filed: May 24, 2011
    Publication date: September 15, 2011
    Inventors: Leeshawn Luo, Anup Bhalla, Yueh-Se Ho, Sik K. Lui, Mike Chang
  • Patent number: 8008716
    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: September 17, 2006
    Date of Patent: August 30, 2011
    Assignee: Alpha & Omega Semiconductor, Ltd
    Inventors: Sik K Lui, François Hébert, Anup Bhalla
  • Publication number: 20110204440
    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: Application
    Filed: April 28, 2011
    Publication date: August 25, 2011
    Inventors: Anup Bhalla, Sik K. Lui
  • 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: 7960233
    Abstract: This invention discloses a new trenched vertical semiconductor power device that includes a capacitor formed between a conductive layer covering over an inter-dielectric layer disposed on top of a trenched gate. In a specific embodiment, the trenched vertical semiconductor power device may be a trenched metal oxide semiconductor field effect transistor (MOSFET) power device. The trenched gate is a trenched polysilicon gate and the conductive layer is a second polysilicon layer covering an inter-poly dielectric layer disposed on top of the trenched polysilicon gate. The conductive layer is further connected to a source of the vertical power device.
    Type: Grant
    Filed: August 21, 2010
    Date of Patent: June 14, 2011
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Sik K. Lui, Anup Bhalla
  • Patent number: 7936011
    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: December 11, 2009
    Date of Patent: May 3, 2011
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Anup Bhalla, Sik K Lui
  • Publication number: 20110097885
    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: Application
    Filed: December 23, 2010
    Publication date: April 28, 2011
    Inventors: Anup Bhalla, Sik K. Lui
  • Publication number: 20110042724
    Abstract: This invention discloses an improved MOSFET devices manufactured with a trenched gate by forming the sidewalls of the trench on a (110) crystal orientation of a semiconductor substrate. The trench is covering with a dielectric oxide layer along the sidewalls and the bottom surface or the termination of the trench formed along different crystal orientations of the semiconductor substrate. Special manufacturing processes such as oxide annealing process, special mask or SOG processes are implemented to overcome the limitations of the non-uniform dielectric layer growth.
    Type: Application
    Filed: April 20, 2009
    Publication date: February 24, 2011
    Inventors: Anup Bhalla, Sik K. Lui, Sung-Shan Tai
  • Patent number: 7863675
    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: March 22, 2008
    Date of Patent: January 4, 2011
    Assignee: Alpha & Omega Semiconductor, Ltd.
    Inventors: Anup Bhalla, Sik K. Lui
  • Publication number: 20100330767
    Abstract: This invention discloses a new trenched vertical semiconductor power device that includes a capacitor formed between a conductive layer covering over an inter-dielectric layer disposed on top of a trenched gate. In a specific embodiment, the trenched vertical semiconductor power device may be a trenched metal oxide semiconductor field effect transistor (MOSFET) power device. The trenched gate is a trenched polysilicon gate and the conductive layer is a second polysilicon layer covering an inter-poly dielectric layer disposed on top of the trenched polysilicon gate. The conductive layer is further connected to a source of the vertical power device.
    Type: Application
    Filed: August 21, 2010
    Publication date: December 30, 2010
    Inventors: Sik K. Lui, Anup Bhalla
  • Publication number: 20100258897
    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: Application
    Filed: June 14, 2010
    Publication date: October 14, 2010
    Inventors: Sik K. Lui, Anup Bhalla
  • Patent number: 7786531
    Abstract: This invention discloses a new trenched vertical semiconductor power device that includes a capacitor formed between a conductive layer covering over an inter-dielectric layer disposed on top of a trenched gate. In a specific embodiment, the trenched vertical semiconductor power device may be a trenched metal oxide semiconductor field effect transistor (MOSFET) power device. The trenched gate is a trenched polysilicon gate and the conductive layer is a second polysilicon layer covering an inter-poly dielectric layer disposed on top of the trenched polysilicon gate. The conductive layer is further connected to a source of the vertical power device.
    Type: Grant
    Filed: July 14, 2005
    Date of Patent: August 31, 2010
    Assignee: Alpha & Omega semiconductor Ltd.
    Inventors: Sik K. Lui, Anup Bhalla
  • Patent number: 7764105
    Abstract: This invention discloses a new MOSFET device. The MOSFET device has an improved operation characteristic achieved by connecting a shunt FET of low impedance to the MOSFET device. The shunt FET is to shunt a transient current therethrough. The shunt FET is employed for preventing an inadvertent turning on of the MOSFET device. The inadvertent turning on of the MOSFET may occur when a large voltage transient occurs at the drain of the MOSFET device. By connecting the gate of the shunt FET to the drain of the MOSFET device, a low impedance path is provided at the right point of time during the circuit operation to shunt the current without requiring any external circuitry.
    Type: Grant
    Filed: May 27, 2008
    Date of Patent: July 27, 2010
    Assignee: Alpha & Omega Semiconductor, Ltd
    Inventors: Anup Bhalla, Sik K. Lui
  • Patent number: 7755379
    Abstract: This invention discloses a circuit for performing an unclamped inductive test on a metal oxide semiconductor field effect transistor (MOSFET) device driven by a gate driver. The circuit includes a current sense circuit for measuring an unclamped inductive testing (UIS) current that increases with an increase of a pulse width inputted from the gate driver to the MOSFET device wherein the current sensing circuit is provided to turn off the gate driver when a predefined UIS current is reached. The test circuit further includes a MOSFET failure detection circuit connected to a drain terminal of the MOSFET device for measuring a drain voltage change for detecting the MOSFET failure during the UIS test. The test circuit further includes a first switch for switching ON/OFF a power supply to the MOSFET device to and a second switch connected between a drain and source terminal of the MOSFET.
    Type: Grant
    Filed: April 8, 2008
    Date of Patent: July 13, 2010
    Assignee: Alpha & Omega Semiconductor, Ltd
    Inventors: Sik K Lui, Anup Bhalla
  • Patent number: 7745878
    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 active cell further includes a trenched source contact opened between the trenches wherein the trenched source contact opened through a source region into a body region for electrically connecting the source region to a source metal disposed on top of an insulation layer wherein a trench bottom surface of the trenched source contact further covered with a conductive material to function as an integrated Schottky barrier diode in said active cell. A shielding structure is disposed at the bottom and insulated from the trenched gate to provide shielding effect for both the trenched gate and the Schottky diode.
    Type: Grant
    Filed: November 18, 2008
    Date of Patent: June 29, 2010
    Assignee: Alpha & Omega Semiconductor, Ltd
    Inventors: Anup Bhalla, Sik K Lui
  • Publication number: 20100148246
    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: Application
    Filed: February 9, 2010
    Publication date: June 17, 2010
    Inventors: Anup Bhalla, Daniel Ng, Tiesheng Li, Sik K. Lui
  • Patent number: 7737522
    Abstract: A Schottky diode includes at least a trenched opened in a semiconductor substrate doped with a dopant of a first conductivity type wherein the trench is filled with a Schottky junction barrier metal. The Schottky diode further includes one or more dopant region of a second conductivity type surrounding sidewalls of the trench distributed along the depth of the trench for shielding a reverse leakage current through the sidewalls of the trench. The Schottky diode further includes a bottom-doped region of the second conductivity type surrounding a bottom surface of the trench and a top-doped region of the second conductivity type surrounding a top portion of the sidewalls of the trench. In a preferred embodiment, the first conductivity type is a N-type conductivity type and the middle-depth dopant region comprising a P-dopant region.
    Type: Grant
    Filed: September 30, 2006
    Date of Patent: June 15, 2010
    Assignee: Alpha & Omega Semiconductor, Ltd.
    Inventors: Sik K Lui, Anup Bhalla
  • Publication number: 20100090276
    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: Application
    Filed: December 11, 2009
    Publication date: April 15, 2010
    Inventors: Anup Bhalla, Sik K. Lui
  • Patent number: 7671662
    Abstract: A semiconductor power device includes a circuit to provide a gate signal wherein the gate signal has a negative temperature coefficient of gate driving voltage for decreasing a gate driving voltage with an increase temperature whereby the semiconductor power device has a net Ids temperature coefficient that is less than or equal to zero. In an exemplary embodiment, the gate voltage driver includes a diode that has a negative forward voltage temperature coefficient connected between a gate and a source of the semiconductor power device. In another embodiment, the gate voltage is integrated with the semiconductor power device manufactured as part of an integrated circuit with the semiconductor power device.
    Type: Grant
    Filed: October 28, 2008
    Date of Patent: March 2, 2010
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Sik K Lui, Anup Bhalla, Sanjay Havanur
  • Patent number: 7659570
    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: May 9, 2005
    Date of Patent: February 9, 2010
    Assignee: Alpha & Omega Semiconductor Ltd.
    Inventors: Anup Bhalla, Daniel Ng, Tiesheng Li, Sik K. Lui