Patents by Inventor Shunhua Thomas Chang

Shunhua Thomas 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).

  • Patent number: 8614489
    Abstract: A vertical NPNP structure fabricated using a triple well CMOS process, as well as methods of making the vertical NPNP structure, methods of providing electrostatic discharge (ESD) protection, and design structures for a BiCMOS integrated circuit. The vertical NPNP structure may be used to provide on-chip protection to an input/output (I/O) pad from negative-voltage ESD events. A vertical PNPN structure may be also used to protect the same I/O pad from positive-voltage ESD events.
    Type: Grant
    Filed: September 13, 2012
    Date of Patent: December 24, 2013
    Assignee: International Business Machines Corporation
    Inventors: John B. Campi, Shunhua Thomas Chang, Kiran V. Chatty, Robert J. Gauthier, Jr., Junjun Li, Rahul Mishra, Mujahid Muhammad
  • Patent number: 7648869
    Abstract: Semiconductor structures and methods for suppressing latch-up in bulk CMOS devices. The structure comprises a first doped well formed in a substrate of semiconductor material, a second doped well formed in the substrate proximate to the first doped well, and a deep trench defined in the substrate. The deep trench includes sidewalls positioned between the first and second doped wells. A buried conductive region is defined in the semiconductor material bordering the base and the sidewalls of the deep trench. The buried conductive region intersects the first and second doped wells. The buried conductive region has a higher dopant concentration than the first and second doped wells. The buried conductive region may be formed by solid phase diffusion from a mobile dopant-containing material placed in the deep trench. After the buried conductive region is formed, the mobile dopant-containing material may optionally remain in the deep trench.
    Type: Grant
    Filed: January 12, 2006
    Date of Patent: January 19, 2010
    Assignee: International Business Machines Corporation
    Inventors: Shunhua Thomas Chang, Toshiharu Furukawa, Robert J. Gauthier, Jr., David Vaclav Horak, Charles William Koburger, III, Jack Allan Mandelman, William Robert Tonti
  • Patent number: 7385275
    Abstract: A semiconductor structure and associated method for forming the semiconductor structure. The semiconductor structure comprises a first field effect transistor (FET), a second FET, and a shallow trench isolation (STI) structure. The first FET comprises a channel region formed from a portion of a silicon substrate, a gate dielectric formed over the channel region, and a gate electrode comprising a bottom surface in direct physical contact with the gate dielectric. A top surface of the channel region is located within a first plane and the bottom surface of the gate electrode is located within a second plane. The STI structure comprises a conductive STI fill structure. A top surface of the conductive STI fill structure is above the first plane by a first distance D1 and is above the second plane by a second distance D2 that is less than D1.
    Type: Grant
    Filed: February 15, 2006
    Date of Patent: June 10, 2008
    Assignee: International Business Machines Corporation
    Inventors: Ethan Harrison Cannon, Shunhua Thomas Chang, Toshiharu Furukawa, David Vaclav Horak, Charles William Koburger, III