PATENT COVER GRAPHIC


United States Patent 4,141,022
February 20, 1979

Refractory Metal Contacts For IGFETs
Hans J. Sigg
Ching W. S. Lai
Warren C. Rosvold


Filed September 12, 1977
Image of US PATENT 4,141,022

Abstract of the Disclosure

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 slilcide 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.
Figure descriptions: cover graphic

  • a diagrammatic view illustrating one stage of fabricating a polysilicon gate IGFET constructed according to the invention.

 Citations [54]:
  
3,906,540 09/1975 Hollins
National Museum of American History
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