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: 20160064551
    Abstract: Aspects of the present disclosure describe a high density trench-based power MOSFET with self-aligned source contacts. The source contacts are self-aligned with a first insulative spacer and a second insulative spacer, wherein the first spacer is resistant to an etching process that will selectively remove the material the second spacer is made from. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
    Type: Application
    Filed: November 10, 2015
    Publication date: March 3, 2016
    Inventors: Yeeheng Lee, Hong Chang, Jongoh Kim, Sik Lui, Hamza Yilmaz, Madhur Bobde, Daniel Calafut, John Chen
  • Patent number: 9269805
    Abstract: Aspects of the present disclosure describe a trench MOSFET with a channel length that may be controlled by counterdoping the body-drain junction to form a straggle region adjacent to the trenches. The channel length is defined between the straggle region at the bottom and a source region at the top. Both of the straggle region and the source region are of the same conductivity type though they may be different ion species. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
    Type: Grant
    Filed: August 27, 2015
    Date of Patent: February 23, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Sik Lui
  • Patent number: 9252264
    Abstract: Aspects of the present disclosure describe a high density trench-based power MOSFETs with self-aligned source contacts and methods for making such devices. The source contacts are self-aligned with spacers and the active devices may have a two-step gate oxide. A lower portion may have a thickness that is larger than the thickness of an upper portion of the gate oxide. The MOSFETS also may include a depletable shield in a lower portion of the substrate. The depletable shield may be configured such that during a high drain bias the shield substantially depletes. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
    Type: Grant
    Filed: December 10, 2014
    Date of Patent: February 2, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Madhur Bobde, Hamza Yilmaz, Sik Lui, Daniel Ng
  • Patent number: 9246347
    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: Grant
    Filed: December 10, 2013
    Date of Patent: January 26, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Sik Lui, Wei Wang
  • Patent number: 9230957
    Abstract: Aspects of the present disclosure describe MOSFET devices that have snubber circuits. The snubber circuits comprise one or more resistors with a dynamically controllable resistance that is controlled by changes to a gate and/or drain potentials of the one or more MOSFET structures during switching events.
    Type: Grant
    Filed: July 16, 2013
    Date of Patent: January 5, 2016
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Sik Lui, Ji Pan
  • Publication number: 20150380544
    Abstract: Aspects of the present disclosure describe a high density trench-based power. The active devices may have a two-step gate oxide. A lower portion may have a thickness that is larger than the thickness of an upper portion of the gate oxide. A lightly doped sub-body layer may be formed below a body region between two or more adjacent active device structures of the plurality. The sub-body layer extends from a depth of the upper portion of the gate oxide to a depth of the lower portion of the gate oxide It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
    Type: Application
    Filed: September 3, 2015
    Publication date: December 31, 2015
    Inventors: Hamza Yilmaz, Madhur Bobde, Hong Chang, Yeeheng Lee, Daniel Calafut, Jongoh Kim, Sik Lui, John Chen
  • Publication number: 20150372133
    Abstract: Aspects of the present disclosure describe a trench MOSFET with a channel length that may be controlled by counterdoping the body-drain junction to form a straggle region adjacent to the trenches. The channel length is defined between the straggle region at the bottom and a source region at the top. Both of the straggle region and the source region are of the same conductivity type though they may be different ion species. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
    Type: Application
    Filed: August 27, 2015
    Publication date: December 24, 2015
    Inventor: Sik Lui
  • Patent number: 9219003
    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. Source and body regions inside the active region are at source potential and source and body regions outside the isolation trench are at drain potential. The device can be made using a three-mask or four-mask process.
    Type: Grant
    Filed: January 27, 2015
    Date of Patent: December 22, 2015
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Sik Lui, Anup Bhalla
  • Patent number: 9214545
    Abstract: A semiconductor device has a plurality of gate electrodes over a gate insulator layer formed in active trenches located in an active region of a semiconductor substrate. A first gate runner is formed in the semiconductor substrate and electrically connected to the gate electrodes. The first gate runner abuts and surrounds the active region. A second gate runner is connected to the first gate runner to make contact to a gate metal. A dielectric filled trench surrounds the first and second gate runners and the active region and a highly doped channel stop region is formed under the dielectric filled trench.
    Type: Grant
    Filed: December 8, 2014
    Date of Patent: December 15, 2015
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Sung-Shan Tai, Sik Lui, Xiaobin Wang
  • Patent number: 9190512
    Abstract: Aspects of the present disclosure describe a high density trench-based power MOSFET with self-aligned source contacts. The source contacts are self-aligned with a first insulative spacer and a second insulative spacer, wherein the first spacer is resistant to an etching process that will selectively remove the material the second spacer is made from. Additionally, the active devices may have a two-step gate oxide, wherein a lower portion of the gate oxide has a thickness T2 that is larger than the thickness T1 of an upper portion of the gate oxide. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
    Type: Grant
    Filed: January 27, 2015
    Date of Patent: November 17, 2015
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Yeeheng Lee, Hong Chang, Jongoh Kim, Sik Lui, Hamza Yilmaz, Madhur Bobde, Daniel Calafut, John Chen
  • Publication number: 20150311295
    Abstract: Embodiments of the present disclosure provide a contact structure in a split-gate trench transistor device for electrically connecting the top electrode to the bottom electrode inside the trench. The transistor device comprises a semiconductor substrate and one or more trenches formed in the semiconductor substrate. The trenches are lined with insulating materials along the sidewalls inside the trenches. Each trench has a bottom electrode in lower portions of the trench and a top electrode in its upper portions. The bottom electrode and the top electrode are separated by an insulating material. A contact structure filled with conductive materials is formed in each trench in an area outside of an active region of the device to connect the top electrode and the bottom electrode. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure.
    Type: Application
    Filed: April 23, 2014
    Publication date: October 29, 2015
    Applicant: Alpha and Omega Semiconductor Incorporated
    Inventors: Yeeheng Lee, Sik Lui, Jongoh Kim, Hong Chang, Madhur Bobde, Lingpeng Guan, Hamza Yilmaz
  • Patent number: 9171917
    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: January 23, 2014
    Date of Patent: October 27, 2015
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Madhur Bobde, Sik Lui, Anup Bhalla
  • Patent number: 9136370
    Abstract: A trench formed in a body layer and epitaxial layer of a substrate is lined with a dielectric layer. A shield electrode formed within a lower portion of the trench is insulated by the dielectric layer. A gate electrode formed in the trench above the shield electrode is insulated from the shield electrode by another dielectric layer. One or more source regions formed within the body layer is adjacent a sidewall of the trench. A source pad formed above the body layer is electrically connected to the source regions and insulated from the gate electrode and shield electrode. The source pad provides an external contact to the source region. A gate pad provides an external contact to the gate electrode. A shield electrode pad provides an external contact to the shield electrode. A resistive element is electrically connected between the shield electrode pad and a source lead.
    Type: Grant
    Filed: June 3, 2014
    Date of Patent: September 15, 2015
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Sik Lui, Yi Su, Daniel Ng, Daniel Calafut, Anup Bhalla
  • Patent number: 9136380
    Abstract: Aspects of the present disclosure describe a high density trench-based power MOSFETs with self-aligned source contacts and methods for making such devices. The source contacts are self-aligned with spacers that are formed along the sidewall of the gate caps. Additionally, the active devices may have a two-step gate oxide. A lower portion may have a thickness that is larger than the thickness of an upper portion of the gate oxide. The two-step gate oxide combined with the self-aligned source contacts allow for the production of devices with a pitch in the deep sub-micron level. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
    Type: Grant
    Filed: July 11, 2014
    Date of Patent: September 15, 2015
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Hamza Yilmaz, Madhur Bobde, Hong Chang, Yeeheng Lee, Daniel Calafut, Jongoh Kim, Sik Lui, John Chen
  • Patent number: 9136060
    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: Grant
    Filed: December 28, 2007
    Date of Patent: September 15, 2015
    Assignee: VISHAY-SILICONIX
    Inventors: Haim Goldberger, Sik Lui, Jacek Korec, Y. Mohammed Kasem, Harianto Wong, Jack Van Den Heuvel
  • Patent number: 9123805
    Abstract: Aspects of the present disclosure describe a trench MOSFET with a channel length that may be controlled by counterdoping the body-drain junction to form a straggle region adjacent to the trenches. The channel length is defined between the straggle region at the bottom and a source region at the top. Both of the straggle region and the source region are of the same conductivity type though they may be different ion species.
    Type: Grant
    Filed: November 14, 2013
    Date of Patent: September 1, 2015
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventor: Sik Lui
  • Publication number: 20150171201
    Abstract: A transistor 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: March 2, 2015
    Publication date: June 18, 2015
    Inventors: Sik Lui, Anup Bhalla
  • Publication number: 20150162777
    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: December 10, 2013
    Publication date: June 11, 2015
    Inventors: Sik Lui, Wei Wang
  • Publication number: 20150145037
    Abstract: Aspects of the present disclosure describe a high density trench-based power MOSFET with self-aligned source contacts. The source contacts are self-aligned with a first insulative spacer and a second insulative spacer, wherein the first spacer is resistant to an etching process that will selectively remove the material the second spacer is made from. Additionally, the active devices may have a two-step gate oxide, wherein a lower portion of the gate oxide has a thickness T2 that is larger than the thickness T1 of an upper portion of the gate oxide. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
    Type: Application
    Filed: January 27, 2015
    Publication date: May 28, 2015
    Inventors: Yeeheng Lee, Hong Chang, Jongoh Kim, Sik Lui, Hamza Yilmaz, Madhur Bobde, Daniel Calafut, John Chen
  • Publication number: 20150137227
    Abstract: Aspects of the present disclosure describe a high density trench-based power MOSFETs with self-aligned source contacts and methods for making such devices. The source contacts are self-aligned with spacers and the active devices may have a two-step gate oxide. A lower portion may have a thickness that is larger than the thickness of an upper portion of the gate oxide. The MOSFETS also may include a depletable shield in a lower portion of the substrate. The depletable shield may be configured such that during a high drain bias the shield substantially depletes. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
    Type: Application
    Filed: December 10, 2014
    Publication date: May 21, 2015
    Inventors: Madhur Bobde, Hamza Yilmaz, Sik Lui, Daniel Ng