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Expired Canadian patentCanada

Buried contact structure for reducing resistance in integrated circuits

CA 1285663 C · Owner: Edwards, Nathen P. · Inventors: Edwards, Nathen P.

CIPO record

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

A buried contact structure to decrease the spreading resistance of various circuit elements of semiconductor devices such as transistors and for reducing the resistance of polysilicon wires typically used in short lengths to connect the circuit elements to other metallic wires. The buried contact structure more specifically includes a phosphorous diffusion superimposed on the field implant which includes the source and/or drain of the transistor device. An overlayed layer of polysilicon is then disposed to make contact with the buried contact diffusion. The field implant used for the source and drain may, for example, be boron. The buried contact structure has a lower resistance than the …

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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.

Why it's free to use

  • Granted July 2, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended July 2, 2008.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledMarch 19, 1987
GrantedJuly 2, 1991
Term endedJuly 2, 2008
Patent numberCA 1285663 C
Classification (IPC)H01L27/04 +2 more

Timeline

Timeline From CIPO dates

1988199119941997200020032006Application filedMarch 19, 1987Patent grantedJuly 2, 1991Term endedJuly 2, 2008

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.