Patents by Inventor James Yakura

James Yakura 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: 6348808
    Abstract: A test transistor structure formed in a semiconductor device has a thick-oxide transistor with an elongated serpentine-shaped metal gate. The gate is used to first measure the threshold voltage of the thick-oxide test structure. Then, a current is passed through the elongated metal line which forms the serpentine gate to heat the area of the test structure. While being heated, a stress voltage is applied between the substrate and one end of the gate electrode, this stress voltage being much larger than the logic voltage used in operating thin-oxide transistors on the chip. After a selected time, the current is removed, the stress voltage is removed, and the threshold voltage of the thick-oxide transistor is again measured and compared to the original value. Any reduction in threshold voltage can be attributed to the migration of positive charge to the silicon-to-oxide interface beneath the gate, and is proportional to the area between the source and drain regions of the test transistor.
    Type: Grant
    Filed: June 25, 1999
    Date of Patent: February 19, 2002
    Assignee: LSI Logic Corporation
    Inventor: James Yakura