Patents by Inventor Shunhua T. Chang

Shunhua T. Chang 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: 20120091530
    Abstract: An electrostatic discharge (ESD) protection device for an integrated circuit includes a buried layer of a first polarity type formed in a substrate of a second polarity type. A well region of the second polarity type is formed above the buried layer. An FET of the first polarity type is formed within the well region. An inner pair of shallow wells of the first polarity type is disposed adjacent to source and drain diffusion regions of the FET, the inner pair of shallow wells having a depth such that a bottom of the inner pair of shallow wells is above a top of the buried layer. An outer pair of deep wells of the first polarity type extends down to the top of the buried layer such that the outer pair of deep wells and the buried layer define a perimeter of the well region of the second polarity type.
    Type: Application
    Filed: October 19, 2010
    Publication date: April 19, 2012
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: John B. Campi, JR., Shunhua T. Chang, Kiran V. Chatty, Robert J. Gauthier, JR., Junjun Li, Rahul Mishra, Mujahid Muhammad
  • Publication number: 20120043583
    Abstract: A low leakage, low capacitance diode based triggered electrostatic discharge (ESD) silicon controlled rectifiers (SCR), methods of manufacture and design structure are provided. The method includes providing a silicon film on an insulator layer. The method further includes forming isolation regions which extend from an upper side of the silicon layer to the insulator layer. The method further includes forming one or more diodes in the silicon layer, including a p+ region and an n+ region formed in a well bordered by the isolation regions. The isolation regions isolate the one or more diodes in a vertical direction and the insulator layer isolates the one or more diodes from an underlying P or N type substrate, in a horizontal direction.
    Type: Application
    Filed: August 20, 2010
    Publication date: February 23, 2012
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Michel J. ABOU-KHALIL, Shunhua T. CHANG, Kiran V. CHATTY, Robert J. GAUTHIER, JR., Junjun LI, Mujahid MUHAMMAD
  • Publication number: 20110286135
    Abstract: An enhanced turn-on time SCR based electrostatic discharge (ESD) protection circuit includes an integrated JFET, method of use and design structure. The enhanced turn-on time silicon controlled rectifier (SCR) based electrostatic discharge (ESD) protection circuit includes an integrated JFET in series with an NPN base.
    Type: Application
    Filed: May 18, 2010
    Publication date: November 24, 2011
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: John B. CAMPI, JR., Shunhua T. CHANG, Kiran V. CHATTY, Robert J. GAUTHIER, JR., Mujahid MUHAMMAD
  • Publication number: 20100265622
    Abstract: A robust ESD protection circuit, method and design structure for tolerant and failsafe designs are disclosed. A circuit includes a middle junction control circuit that turns off a top NFET of a stacked NFET electrostatic discharge (ESD) protection circuit during an ESD event.
    Type: Application
    Filed: April 15, 2009
    Publication date: October 21, 2010
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: John B. CAMPI, JR., Shunhua T. CHANG, Kiran V. CHATTY, Robert J. GAUTHIER, JR., Junjun LI, Mujahid MUHAMMAD
  • Publication number: 20100246076
    Abstract: A semiconductor circuit for electric overstress (EOS) protection is provided. The semiconductor circuit employs an electrostatic discharge (ESD) protection circuit, which has a resistor-capacitor (RC) time-delay network connected to a discharge capacitor. An electronic component that has voltage snapback property or a diodic behavior is connected to alter the logic state of the gate of the discharge transistor under an EOS event. Particularly, the electronic component is configured to turn on the gate of the discharge capacitor throughout the duration of an electrical overstress (EOS) condition as well as throughout the duration of an ESD event. A design structure may be employed to design or manufacture a semiconductor circuit that provides protection against an EOS condition without time limitation, i.e., without being limited by the time constant of the RC time delay network for EOS events that last longer than 1 microsecond.
    Type: Application
    Filed: December 7, 2009
    Publication date: September 30, 2010
    Applicant: International Business Machines Corporation
    Inventors: John B. Campi, JR., Shunhua T. Chang, Kiran V. Chatty, Robert J. Gauthier, JR., Junjun Li, Mujahid Muhammad
  • Publication number: 20100181621
    Abstract: An integrated circuit, design structures and methods of forming the integrated circuit which includes a signal pad ESD coupled to an I/O signal pad and a power supply ESD coupled to a source VDD. The signal pad ESD and the power supply ESD are integrated in a single ESD structure.
    Type: Application
    Filed: January 19, 2009
    Publication date: July 22, 2010
    Applicant: International Business Machines Corporation
    Inventors: Shunhua T. Chang, Kiran V. Chatty, Robert J. Gauthier, JR., Mujahid Muhammad
  • Publication number: 20070297105
    Abstract: A system and method of electrostatic discharge (ESD) protection in a logic circuit using either state manipulation or current injection. A first system is disclosed that includes an ESD detection circuit for detecting an ESD event; and an ESD control circuit that can change a state of the logic circuit from a normal mode to an ESD mode in response to a signal received from the ESD detection circuit. A second system is disclosed that includes an attenuator circuit coupled to a chip pad; and a switch for diverting current from the attenuator circuit to an internal node of the logic circuit during an ESD event to reduce a voltage at the chip pad.
    Type: Application
    Filed: June 23, 2006
    Publication date: December 27, 2007
    Inventors: Ciaran J. Brennan, Shunhua T. Chang