Patents by Inventor Yuming Bai

Yuming Bai 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: 20080258212
    Abstract: Remote contacts to the polysilicon regions of a trench metal oxide semiconductor (MOS) barrier Schottky (TMBS) device, as well as to the polysilicon regions of a MOS field effect transistor (MOSFET) section and of a TMBS section in a monolithically integrated TMBS and MOSFET (SKYFET) device, are employed. The polysilicon is recessed relative to adjacent mesas. Contact of the source metal to the polysilicon regions of the TMBS section is made through an extension of the polysilicon to outside the active region of the TMBS section. This change in the device architecture relieves the need to remove all of the oxides from both the polysilicon and silicon mesa regions of the TMBS section prior to the contact step. As a consequence, encroachment of contact metal into the sidewalls of the trenches in a TMBS device, or in a SKYFET device, is avoided.
    Type: Application
    Filed: April 7, 2008
    Publication date: October 23, 2008
    Applicant: VISHAY-SILICONIX
    Inventors: Deva N. Pattanayak, Kyle Terrill, Sharon Shi, Misha Lee, Yuming Bai, Kam Lui, Kuo-In Chen
  • Publication number: 20080182376
    Abstract: In a trench MOSFET, the lower portion of the trench contains a buried source electrode, which is insulated from the epitaxial layer and semiconductor substrate but in electrical contact with the source region. When the MOSFET is in an “off” condition, the bias of the buried source electrode causes the “drift” region of the mesa to become depleted, enhancing the ability of the MOSFET to block current. The doping concentration of the drift region can therefore be increased, reducing the on-resistance of the MOSFET. The buried source electrode also reduces the gate-to-drain capacitance of the MOSFET, improving the ability of the MOSFET to operate at high frequencies. The substrate may advantageously include a plurality of annular trenches separated by annular mesas and a gate metal layer that extends outward from a central region in a plurality of gate metal legs separated by source metal regions.
    Type: Application
    Filed: March 31, 2008
    Publication date: July 31, 2008
    Applicant: Siliconix incorporated
    Inventors: Deva N. Pattanayak, Yuming Bai, Kyle Terrill, Christiana Yue, Robert Xu, Kam Hong Lui, Kuo-In Chen, Sharon Shi
  • Patent number: 7344945
    Abstract: Embodiments of the present invention provide a striped or closed cell trench metal-oxide-semiconductor field effect transistor (TMOSFET). The striped or closed cell TMOSFET comprises a source region, a body region disposed above the source region, a drift region disposed above the body region, a drain region disposed above the drift region. A gate region is disposed above the source region and adjacent the body region. A gate insulator region electrically isolates the gate region from the source region, body region, drift region and drain region. The body region is electrically coupled to the source region.
    Type: Grant
    Filed: December 22, 2004
    Date of Patent: March 18, 2008
    Assignee: Vishay-Siliconix
    Inventors: Deva Pattanayak, Jason (Jianhai) Qi, Yuming Bai, Kam-Hong Lui, Ronald Wong
  • Publication number: 20070187753
    Abstract: In a trench MOSFET, the lower portion of the trench contains a buried source electrode, which is insulated from the epitaxial layer and semiconductor substrate but in electrical contact with the source region. When the MOSFET is in an “off” condition, the bias of the buried source electrode causes the “drift” region of the mesa to become depleted, enhancing the ability of the MOSFET to block current. The doping concentration of the drift region can therefore be increased, reducing the on-resistance of the MOSFET. The buried source electrode also reduces the gate-to-drain capacitance of the MOSFET, improving the ability of the MOSFET to operate at high frequencies. The substrate may advantageously include a plurality of annular trenches separated by annular mesas and a gate metal layer that extends outward from a central region in a plurality of gate metal legs separated by source metal regions.
    Type: Application
    Filed: January 26, 2007
    Publication date: August 16, 2007
    Applicant: Siliconix incorporated
    Inventors: Deva Pattanayak, Yuming Bai, Kyle Terrill, Christiana Yue, Robert Xu, Kam Lui, Kuo-In Chen, Sharon Shi
  • Publication number: 20070063340
    Abstract: A complete power management system implemented in a single surface mount package. The system may be drawn to a DC to DC converter system and includes, in a leadless surface mount package, a driver/controller, a MOSFET transistor, passive components (e.g., inductor, capacitor, resistor), and optionally a diode. The MOSFET transistor may be replaced with an insulated gate bipolar transistor, IGBT in various embodiments. The system may also be a power management system, a smart power module or a motion control system. The passive components may be connected between the leadframe connections. The active components may be coupled to the leadframe using metal clip bonding techniques. In one embodiment, an exposed metal bottom may act as an effective heat sink.
    Type: Application
    Filed: June 30, 2006
    Publication date: March 22, 2007
    Inventors: King Owyang, Mohammed Kasem, Yuming Bai, Frank Kuo, Sen Mao, Sam Kuo
  • Publication number: 20070063341
    Abstract: A complete power management system implemented in a single surface mount package. The system may be drawn to a DC to DC converter system and includes, in a leadless surface mount package, a driver/controller, a MOSFET transistor, passive components (e.g., inductor, capacitor, resistor), and optionally a diode. The MOSFET transistor may be replaced with an insulated gate bipolar transistor, IGBT in various embodiments. The system may also be a power management system, a smart power module or a motion control system. The passive components may be connected between the leadframe connections. The active components may be coupled to the leadframe using metal clip bonding techniques. In one embodiment, an exposed metal bottom may act as an effective heat sink.
    Type: Application
    Filed: June 30, 2006
    Publication date: March 22, 2007
    Inventors: King Owyang, Mohammed Kasem, Yuming Bai, Frank Kuo, Sen Mao, Sam Kuo
  • Patent number: 7183610
    Abstract: In a trench MOSFET, the lower portion of the trench contains a buried source electrode, which is insulated from the epitaxial layer and semiconductor substrate but in electrical contact with the source region. When the MOSFET is in an “off” condition, the bias of the buried source electrode causes the “drift” region of the mesa to become depleted, enhancing the ability of the MOSFET to block current. The doping concentration of the drift region can therefore be increased, reducing the on-resistance of the MOSFET. The buried source electrode also reduces the gate-to-drain capacitance of the MOSFET, improving the ability of the MOSFET to operate at high frequencies. The substrate may advantageously include a plurality of annular trenches separated by annular mesas and a gate metal layer that extends outward from a central region in a plurality of gate metal legs separated by source metal regions.
    Type: Grant
    Filed: April 30, 2004
    Date of Patent: February 27, 2007
    Assignee: Siliconix incorporated
    Inventors: Deva N. Pattanayak, Yuming Bai, Kyle Terrill, Christiana Yue, Robert Xu, Kam Hong Lui, Kuo-In Chen, Sharon Shi
  • Publication number: 20050242392
    Abstract: In a trench MOSFET, the lower portion of the trench contains a buried source electrode, which is insulated from the epitaxial layer and semiconductor substrate but in electrical contact with the source region. When the MOSFET is in an “off” condition, the bias of the buried source electrode causes the “drift” region of the mesa to become depleted, enhancing the ability of the MOSFET to block current. The doping concentration of the drift region can therefore be increased, reducing the on-resistance of the MOSFET. The buried source electrode also reduces the gate-to-drain capacitance of the MOSFET, improving the ability of the MOSFET to operate at high frequencies. The substrate may advantageously include a plurality of annular trenches separated by annular mesas and a gate metal layer that extends outward from a central region in a plurality of gate metal legs separated by source metal regions.
    Type: Application
    Filed: April 30, 2004
    Publication date: November 3, 2005
    Applicant: Siliconix incorporated
    Inventors: Deva Pattanayak, Yuming Bai, Kyle Terrill, Christiana Yue, Robert Xu, Kam Lui, Kuo-In Chen, Sharon Shi
  • Patent number: 6906380
    Abstract: Embodiments of the present invention provide a striped or closed cell trench metal-oxide-semiconductor field effect transistor (TMOSFET). The striped or closed cell TMOSFET comprises a source region, a body region disposed above the source region, a drift region disposed above the body region, a drain region disposed above the drift region. A gate region is disposed above the source region and adjacent the body region. A gate insulator region electrically isolates the gate region from the source region, body region, drift region and drain region. The body region is electrically coupled to the source region.
    Type: Grant
    Filed: May 13, 2004
    Date of Patent: June 14, 2005
    Assignee: Vishay-Siliconix
    Inventors: Deva Pattanayak, Jason (Jianhai) Qi, Yuming Bai, Kam-Hong Lui, Ronald Wong
  • Patent number: 6737842
    Abstract: A buck regulator having a voltage sensor for sensing a voltage reversal caused by freewheeling current from an output inductor in the regulator. Upon sensing a reversed voltage, the voltage sensor triggers a gate controller to turn on a switch in the regulator, and thereby terminate a dead time. The voltage sensor and gate controller are high speed circuits, and therefore can reduce the duration of the dead time. Reducing the dead time duration improves efficiency by reducing the duration of body diode conduction. The dead time can be reduced to less than a turn-on time of the body diode, thereby preventing charge buildup in the body diode, and, consequently, preventing reverse recovery loss in the body diode. The present invention improves electrical conversion efficiency, and allows for increased operating frequency in buck regulators.
    Type: Grant
    Filed: October 11, 2002
    Date of Patent: May 18, 2004
    Assignee: Virginia Tech Intellectual Properties, Inc.
    Inventors: Yuming Bai, Nick Sun, Alex Q. Huang
  • Publication number: 20040070377
    Abstract: A buck regulator having a voltage sensor for sensing a voltage reversal caused by freewheeling current from an output inductor in the regulator. Upon sensing a reversed voltage, the voltage sensor triggers a gate controller to turn on a switch in the regulator, and thereby terminate a dead time. The voltage sensor and gate controller are high speed circuits, and therefore can reduce the duration of the dead time. Reducing the dead time duration improves efficiency by reducing the duration of body diode conduction. The dead time can be reduced to less than a turn-on time of the body diode, thereby preventing charge buildup in the body diode, and, consequently, preventing reverse recovery loss in the body diode. The present invention improves electrical conversion efficiency, and allows for increased operating frequency in buck regulators.
    Type: Application
    Filed: October 11, 2002
    Publication date: April 15, 2004
    Inventors: Yuming Bai, Nick Sun, Alex Q. Huang
  • Publication number: 20030228679
    Abstract: The invention provides inoculants for increasing plant growth, comprising plant growth promoting bacteria selected from the group consisting of plant growth promoting bacteria of the species Bacillus subtilis and plant growth promoting bacteria of the species Bacillus thuringiensis, or a combination thereof, and methods for using the inoculants for increasing plant growth. Preferably the plant growth promoting bacteria are selected from the group consisting of B. subtilis having the identifying characteristics of B. subtilis strain NEB4, B. subtilis having the identifying characteristics of B. subtilis strain NEB5, and B. thuringiensis having the identifying characteristics of B. thuringiensis strain NEB17.
    Type: Application
    Filed: March 26, 2003
    Publication date: December 11, 2003
    Inventors: Donald L. Smith, Brian Driscoll, Yuming Bai