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).

  • Patent number: 7633119
    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: February 17, 2006
    Date of Patent: December 15, 2009
    Assignee: Alpha & Omega Semiconductor, Ltd
    Inventors: Anup Bhalla, Sik K Lui
  • Patent number: 7633140
    Abstract: A semiconductor package includes a lead frame having a plurality of leads and a lead frame pad, the lead frame pad including a die coupled thereto, at least one of the plurality of leads having an external portion sloped upwards relative to a bottom surface of the package, metal connectors connecting the die to the plurality of leads, and a resin body encapsulating the die, metal connectors and at least a portion of the lead frame.
    Type: Grant
    Filed: December 9, 2003
    Date of Patent: December 15, 2009
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Leeshawn Luo, Anup Bhalla, Sik K. Lui, Yueh-Se Ho, Mike F. Chang, Xiao Tiang Zhang
  • Publication number: 20090219044
    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: Application
    Filed: May 11, 2009
    Publication date: September 3, 2009
    Inventors: Anup Bhalla, Sik K. Lui, Daniel Ng
  • Publication number: 20090218890
    Abstract: This invention discloses a power switch that includes a fast-switch semiconductor power device and a slow-switch semiconductor power device controllable to turn on and off a current transmitting therethrough. The slow-switch semiconductor power device further includes a ballasting resistor for increasing a device robustness of the slow switch semiconductor power device. In an exemplary embodiment, the fast-switch semiconductor power device includes a fast switch metal oxide semiconductor field effect transistor (MOSFET) and the slow-switch semiconductor power device includes a slow switch MOSFET wherein the slow switch MOSFET further includes a source ballasting resistor.
    Type: Application
    Filed: March 3, 2008
    Publication date: September 3, 2009
    Inventors: Sik K. Lui, Anup Bhalla
  • Publication number: 20090128223
    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: Application
    Filed: October 28, 2008
    Publication date: May 21, 2009
    Inventors: Sik K. Lui, Anup Bhalla, Sanjay Havanur
  • Patent number: 7535021
    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: November 1, 2005
    Date of Patent: May 19, 2009
    Assignee: Alpha & Omega Semiconductor, Ltd.
    Inventors: Anup Bhalla, Sik K. Lui, Daniel Ng
  • Publication number: 20090072301
    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: Application
    Filed: November 18, 2008
    Publication date: March 19, 2009
    Inventors: Anup Bhalla, Sik K. Lui
  • Publication number: 20090039456
    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 8, 2007
    Publication date: February 12, 2009
    Inventors: Anup Bhalla, Sik K. Lui, Yi Su
  • Publication number: 20090014853
    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: Application
    Filed: June 23, 2008
    Publication date: January 15, 2009
    Inventors: Leeshawn Luo, Anup Bhalla, Yueh-Se Ho, Sik K. Lui, Mike Chang
  • Publication number: 20080309382
    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: Application
    Filed: May 27, 2008
    Publication date: December 18, 2008
    Inventors: Anup Bhalla, Sik K. Lui
  • Patent number: 7453119
    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: March 10, 2006
    Date of Patent: November 18, 2008
    Assignee: Alphs & Omega Semiconductor, Ltd.
    Inventors: Anup Bhalla, Sik K. Lui
  • Publication number: 20080265289
    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: April 30, 2007
    Publication date: October 30, 2008
    Inventors: Anup Bhalla, Francios Hebert, Sung-Shan Tai, Sik K. Lui
  • Patent number: 7443225
    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: June 30, 2006
    Date of Patent: October 28, 2008
    Assignee: Alpha & Omega Semiconductor, Ltd.
    Inventors: Sik K Lui, Anup Bhalla, Sanjay Havanur
  • Patent number: 7436022
    Abstract: This invention discloses a semiconductor power device that includes an active cell area having a plurality of power transistor cells and a junction barrier Schottky (JBS) area. The semiconductor power device includes the JBS area that further includes a plurality of Schottky diodes each having a PN junction disposed on an epitaxial layer near a top surface of a semiconductor substrate wherein the PN junction further includes a counter dopant region disposed in the epitaxial layer for reducing a sudden reversal of dopant profile near the PN junction for preventing an early breakdown in the PN junction.
    Type: Grant
    Filed: April 29, 2006
    Date of Patent: October 14, 2008
    Assignee: Alpha & Omega Semiconductors, Ltd.
    Inventors: Anup Bhalla, Daniel Ng, Sik K Lui
  • Publication number: 20080186048
    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: Application
    Filed: April 8, 2008
    Publication date: August 7, 2008
    Inventors: Sik K. Lui, Anup Bhalla
  • Publication number: 20080173956
    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: March 22, 2008
    Publication date: July 24, 2008
    Inventors: Anup Bhalla, Sik K. Lui
  • Patent number: 7391100
    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: October 25, 2004
    Date of Patent: June 24, 2008
    Assignee: Alpha & Omega Semiconductor Limited
    Inventors: Leeshawn Luo, Anup Bhalla, Yueh-Se Ho, Sik K. Lui, Mike Chang
  • Patent number: 7378884
    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 21, 2007
    Date of Patent: May 27, 2008
    Assignee: Alpha & Omega Semiconductor, Ltd.
    Inventors: Anup Bhalla, Sik K. Lui
  • Patent number: 7355433
    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: December 14, 2005
    Date of Patent: April 8, 2008
    Assignee: Alpha & Omega Semiconductor, Ltd
    Inventors: Sik K Lui, Anup Bhalla
  • Publication number: 20080067584
    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: September 17, 2006
    Publication date: March 20, 2008
    Inventors: Sik K Lui, Francois Hebert, Anup Bhalla