Patents by Inventor Sik Lui

Sik 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: 20120193676
    Abstract: This invention discloses a semiconductor device disposed in a semiconductor substrate. The semiconductor device includes a first semiconductor layer of a first conductivity type on a first major surface. The semiconductor device further includes a second semiconductor layer of a second conductivity type on a second major surface opposite the first major surface. The semiconductor device further includes an injection efficiency controlling buffer layer of a first conductivity type disposed immediately below the second semiconductor layer to control the injection efficiency of the second semiconductor layer.
    Type: Application
    Filed: January 31, 2011
    Publication date: August 2, 2012
    Inventors: Madhur Bobde, Harsh Naik, Lingpeng Guan, Anup Bhalla, Sik Lui
  • Publication number: 20120146090
    Abstract: Transistor devices can be fabricated with an integrated diode using a self-alignment. The device includes a doped semiconductor substrate having one or more electrically insulated gate electrodes formed in trenches in the substrate. One or more body regions are formed in a top portion of the substrate proximate each gate trench. One or more source regions are formed in a self-aligned fashion in a top portion of the body regions proximate each gate trench. One or more thick insulator portions are formed over the gate electrodes on a top surface of the substrate with spaces between adjacent thick insulator portions. A metal is formed on top of the substrate over the thick insulator portions. The metal forms a self-aligned contact to the substrate through the spaces between the thick insulator portions. An integrated diode is formed under the self-aligned contact.
    Type: Application
    Filed: December 14, 2010
    Publication date: June 14, 2012
    Applicant: Alpha and Omega Semiconductor Incorporated
    Inventors: Sik Lui, Anup Bhalla
  • Publication number: 20120132988
    Abstract: An oxide termination semiconductor device may comprise a plurality of gate trenches, a gate runner, and an insulator termination trench. The gate trenches are located in an active region. Each gate trench includes a conductive gate electrode. The insulator termination trench is located in a termination region that surrounds the active region. The insulator termination trench is filled with an insulator material to form an insulator termination for the semiconductor device. The device can be made using a three-mask or four-mask process.
    Type: Application
    Filed: February 7, 2012
    Publication date: May 31, 2012
    Applicant: Alpha and Omega Semiconductor Incorporated
    Inventors: Sik Lui, Anup Bhalla
  • Publication number: 20120074896
    Abstract: A semiconductor die with integrated MOSFET and diode-connected enhancement mode JFET is disclosed. The MOSFET-JFET die includes common semiconductor substrate region (CSSR) of type-1 conductivity. A MOSFET device and a diode-connected enhancement mode JFET (DCE-JFET) device are located upon CSSR. The DCE-JFET device has the CSSR as its DCE-JFET drain. At least two DCE-JFET gate regions of type-2 conductivity located upon the DCE-JFET drain and laterally separated from each other with a DCE-JFET gate spacing. At least a DCE-JFET source of type-1 conductivity located upon the CSSR and between the DCE-JFET gates. A top DCE-JFET electrode, located atop and in contact with the DCE-JFET gate regions and DCE-JFET source regions. When properly configured, the DCE-JFET simultaneously exhibits a forward voltage Vf substantially lower than that of a PN junction diode while the reverse leakage current can be made comparable to that of a PN junction diode.
    Type: Application
    Filed: September 29, 2010
    Publication date: March 29, 2012
    Inventors: Sik Lui, Wei Wang
  • Publication number: 20110233667
    Abstract: A semiconductor device and fabrication methods are disclosed. The device includes a plurality of gate electrodes formed in trenches located in an active region of a semiconductor substrate. A first gate runner is formed in the substrate and electrically connected to the gate electrodes, wherein the first gate runner surrounds the active region. A second gate runner is connected to the first gate runner and located between the active region and a termination region. A termination structure surrounds the first and second gate runners and the active region. The termination structure includes a conductive material in an insulator-lined trench in the substrate, wherein the termination structure is electrically shorted to a source or body layer of the substrate thereby forming a channel stop for the device.
    Type: Application
    Filed: May 18, 2010
    Publication date: September 29, 2011
    Applicant: Alpha and Omega Semiconductor Incorporated
    Inventors: Sung-Shan Tai, Sik Lui, Xiaobin Wang
  • Publication number: 20110233666
    Abstract: An oxide termination semiconductor device may comprise a plurality of gate trenches, a gate runner, and an insulator termination trench. The gate trenches are located in an active region. Each gate trench includes a conductive gate electrode. The insulator termination trench is located in a termination region that surrounds the active region. The insulator termination trench is filled with an insulator material to form an insulator termination for the semiconductor device. The device can be made using a three-mask or four-mask process.
    Type: Application
    Filed: March 24, 2010
    Publication date: September 29, 2011
    Applicant: Alpha and Omega Semiconductor Incorporated
    Inventors: Sik Lui, Anup Bhalla
  • Patent number: 8004063
    Abstract: A precision high-frequency capacitor includes a dielectric layer formed on the front side surface of a semiconductor substrate and a first electrode on top of the dielectric layer. The semiconductor substrate is heavily doped and therefore has a low resistivity. A second electrode, insulated from the first electrode, is also formed over the front side surface. In one embodiment, the second electrode is connected by a metal-filled via to a layer of conductive material on the back side of the substrate. In alternative embodiments, the via is omitted and the second electrode is either in electrical contact with the substrate or is formed on top of the dielectric layer, yielding a pair of series-connected capacitors. ESD protection for the capacitor can be provided by a pair of oppositely-directed diodes formed in the substrate and connected in parallel with the capacitor.
    Type: Grant
    Filed: November 16, 2006
    Date of Patent: August 23, 2011
    Assignee: Vishay Intertechnology, Inc.
    Inventors: Haim Goldberger, Sik Lui, Jacek Korec, Y. Mohammed Kasem, Harianto Wong, Jack Van Den Heuvel
  • Publication number: 20110176247
    Abstract: A precision high-frequency capacitor includes a dielectric layer formed on the front side surface of a semiconductor substrate and a first electrode on top of the dielectric layer. The semiconductor substrate is heavily doped and therefore has a low resistivity. A second electrode, insulated from the first electrode, is also formed over the front side surface. In one embodiment, the second electrode is connected by a metal-filled via to a layer of conductive material on the back side of the substrate. In alternative embodiments, the via is omitted and the second electrode is either in electrical contact with the substrate or is formed on top of the dielectric layer, yielding a pair of series-connected capacitors. ESD protection for the capacitor can be provided by a pair of oppositely-directed diodes formed in the substrate and connected in parallel with the capacitor.
    Type: Application
    Filed: March 30, 2011
    Publication date: July 21, 2011
    Applicant: VISHAY INTERTECHNOLOGY, INC.
    Inventors: Haim Goldberger, Sik Lui, Jacek Korec, Y. Mohammed Kasem, Harianto Wong, Jack Van Den Heuvel
  • 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
  • Publication number: 20110049580
    Abstract: A hybrid packaged gate controlled semiconductor switching device (HPSD) has an insulated-gate transistor (IGT) made of a first semiconductor die and a rectifying-gate transistor (RGT) made of a second semiconductor die. The RGT gate and source are electrically connected to the IGT source and drain respectively. The HPSD includes a package base with package terminals for interconnecting the HPSD to external environment. The IGT is die bonded atop the package base. The second semiconductor die is formed upon a composite semiconductor epi layer overlaying an electrically insulating substrate (EIS) thus creating a RGT die. The RGT die is stacked and bonded atop the IGT die via the EIS. The IGT, RGT die and package terminals are interconnected with bonding wires. Thus, the HPSD is a stacked package of IGT die and RGT die with reduced package footprint while allowing flexible placements of device terminal electrodes on the IGT.
    Type: Application
    Filed: August 28, 2009
    Publication date: March 3, 2011
    Inventors: Sik Lui, Anup Bhalla
  • Publication number: 20110042742
    Abstract: In a trench-gated MIS device contact is made to the gate within the trench, thereby eliminating the need to have the gate material, typically polysilicon, extend outside of the trench. This avoids the problem of stress at the upper corners of the trench. Contact between the gate metal and the polysilicon is normally made in a gate metal region that is outside the active region of the device. Various configurations for making the contact between the gate metal and the polysilicon are described, including embodiments wherein the trench is widened in the area of contact. Since the polysilicon is etched back below the top surface of the silicon throughout the device, there is normally no need for a polysilicon mask, thereby saving fabrication costs.
    Type: Application
    Filed: November 1, 2010
    Publication date: February 24, 2011
    Applicant: VISHAY-SILICONIX
    Inventors: Anup Bhalla, Dorman Pitzer, Jacek Korec, Xiaorong Shi, Sik Lui
  • Patent number: 7868381
    Abstract: In a trench-gated MIS device contact is made to the gate within the trench, thereby eliminating the need to have the gate material, typically polysilicon, extend outside of the trench. This avoids the problem of stress at the upper corners of the trench. Contact between the gate metal and the polysilicon is normally made in a gate metal region that is outside the active region of the device. Various configurations for making the contact between the gate metal and the polysilicon are described, including embodiments wherein the trench is widened in the area of contact. Since the polysilicon is etched back below the top surface of the silicon throughout the device, there is normally no need for a polysilicon mask, thereby saving fabrication costs.
    Type: Grant
    Filed: November 5, 2007
    Date of Patent: January 11, 2011
    Assignee: Vishay-Siliconix
    Inventors: Anup Bhalla, Domon Pitzer, Jacek Korec, Xiaorong Shi, Sik Lui
  • Publication number: 20100295152
    Abstract: A precision high-frequency capacitor includes a dielectric layer formed on the front side surface of a semiconductor substrate and a first electrode on top of the dielectric layer. The semiconductor substrate is heavily doped and therefore has a low resistivity. A second electrode, insulated from the first electrode, is also formed over the front side surface. In one embodiment, the second electrode is connected by a metal-filled via to a layer of conductive material on the back side of the substrate. In alternative embodiments, the via is omitted and the second electrode is either in electrical contact with the substrate or is formed on top of the dielectric layer, yielding a pair of series-connected capacitors. ESD protection for the capacitor can be provided by a pair of oppositely-directed diodes formed in the substrate and connected in parallel with the capacitor.
    Type: Application
    Filed: November 16, 2006
    Publication date: November 25, 2010
    Inventors: Haim Goldberger, Sik Lui, Jacek Korec, Y. Mohammed Kasem, Harianto Wong, Jack Van Den Heuvel
  • Patent number: 7800169
    Abstract: A semiconductor device comprises a drain, a body disposed over the drain, having a body top surface, a source embedded in the body, extending downward from the body top surface into 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 having a trench wall and an anti-punch through implant that is disposed along the trench wall. A method of fabricating a semiconductor device comprises forming a hard mask on a 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, forming a source body contact trench having a trench wall and forming an anti-punch through implant.
    Type: Grant
    Filed: September 11, 2007
    Date of Patent: September 21, 2010
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Anup Bhalla, Sik Lui, Tiesheng Li
  • Patent number: 7605425
    Abstract: A semiconductor device comprises a drain, a body disposed over the drain, having a body top surface, a source embedded in the body, extending downward from the body top surface into 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 having a trench wall and an anti-punch through implant that is disposed along the trench wall.
    Type: Grant
    Filed: September 11, 2007
    Date of Patent: October 20, 2009
    Assignee: Alpha & Omega Semiconductor Limited
    Inventors: Anup Bhalla, Sik Lui, Tiesheng Li
  • Publication number: 20090224316
    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: Application
    Filed: March 31, 2009
    Publication date: September 10, 2009
    Inventors: Anup Bhalla, Sik Lui, Tiesheng Li
  • Publication number: 20080108202
    Abstract: A method of fabricating a capacitor in a semiconductor substrate. The semiconductor substrate is doped to have a low resistivity. A second electrode, insulated from a first electrode, is formed over a front side surface and connected by a metal-filled via to the back side surface. The via may be omitted and the second electrode may be in electrical contact with the substrate or may be formed on top of the dielectric layer, yielding a pair of series-connected capacitors. ESD protection for the capacitor is provided by a pair of oppositely-directed diodes formed in the substrate connected in parallel with the capacitor. Capacitance is increased while maintaining a low effective series resistance. Electrodes include a plurality of fingers, which are interdigitated with the fingers of other electrode. The capacitor is fabricated in a wafer-scale process with other capacitors, where capacitors are separated from each other by a dicing technique.
    Type: Application
    Filed: December 28, 2007
    Publication date: May 8, 2008
    Applicant: VISHAY-SILICONIX
    Inventors: Haim Goldberger, Sik Lui, Jacek Korec, Y. Kasem, Harianto Wong, Jack Van Den Heuvel
  • Patent number: 7335946
    Abstract: In a trench-gated MIS device contact is made to the gate within the trench, thereby eliminating the need to have the gate material, typically polysilicon, extend outside of the trench. This avoids the problem of stress at the upper corners of the trench. Contact between the gate metal and the polysilicon is normally made in a gate metal region that is outside the active region of the device. Various configurations for making the contact between the gate metal and the polysilicon are described, including embodiments wherein the trench is widened in the area of contact. Since the polysilicon is etched back below the top surface of the silicon throughout the device, there is normally no need for a polysilicon mask, thereby saving fabrication costs.
    Type: Grant
    Filed: July 22, 2004
    Date of Patent: February 26, 2008
    Assignee: Vishay-Siliconix
    Inventors: Anup Bhalla, Dorman Pitzer, Jacek Korec, Xiaorong Shi, Sik Lui
  • Publication number: 20080001219
    Abstract: A semiconductor device comprises a drain, a body disposed over the drain, having a body top surface, a source embedded in the body, extending downward from the body top surface into 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 having a trench wall and an anti-punch through implant that is disposed along the trench wall. A method of fabricating a semiconductor device comprises forming a hard mask on a 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, forming a source body contact trench having a trench wall and forming an anti-punch through implant.
    Type: Application
    Filed: September 11, 2007
    Publication date: January 3, 2008
    Inventors: Anup Bhalla, Sik Lui, Tiesheng Li
  • Publication number: 20080001220
    Abstract: A semiconductor device comprises a drain, a body disposed over the drain, having a body top surface, a source embedded in the body, extending downward from the body top surface into 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 having a trench wall and an anti-punch through implant that is disposed along the trench wall. A method of fabricating a semiconductor device comprises forming a hard mask on a 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, forming a source body contact trench having a trench wall and forming an anti-punch through implant.
    Type: Application
    Filed: September 11, 2007
    Publication date: January 3, 2008
    Inventors: Anup Bhalla, Sik Lui, Tiesheng Li