Patents by Inventor Ching W. S. Lai

Ching W. S. Lai 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: 4141022
    Abstract: A metal contact system for an IGFET having shallow source and drain includes a refractory metal silicide layer forming low resistance ohmic contact to a silicon surface, a layer on the silicide layer of another refractory metal to serve as a barrier against diffusion of the interconnect metal, and a layer of interconnect metal over the diffusion barrier layer. The refractory metal layers are deposited by sputtering platinum or platinel for the first layer and titanium-tungsten for the second layer. In metal gate construction an additional layer of chromium is used as an etch resistant mask to protect the refractory metal layers from chemical attack when removing silicon nitride after it has been used initially as an oxidation mask and later as a sputtering mask.
    Type: Grant
    Filed: September 12, 1977
    Date of Patent: February 20, 1979
    Assignee: Signetics Corporation
    Inventors: Hans J. Sigg, Ching W. S. Lai, Warren C. Rosvold