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Integrated circuit for a chemical-selective sensor with voltage output

  • US 4,743,954 A
  • Filed: 06/07/1985
  • Issued: 05/10/1988
  • Est. Priority Date: 06/07/1985
  • Status: Expired due to Term
First Claim
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1. An integrated circuit for a miniaturized solid-state chemical sensor, said integrated circuit comprising:

  • a semiconductor substrate;

    a plurality of layers formed on said substrate so as to define a plurality of transistors configured as an amplifier, two of said transistors comprising field-effect input transistors with essentially identical dimensions and gate electrodes;

    a chemical-selective membrane;

    a membrane definition layer applied over said layers defining said amplifier, said membrane definition layer comprising a well for receiving said chemical-selective membrane, said well being formed in sufficient proximity to said gate electrode of at least one of said input transistors such that said chemical-selective membrane is separated from said gate electrode by no greater distance than the largest dimension of said input transistors;

    means formed on said substrate for electrically connecting said chemical-selective membrane to said gate electrode of one of said input transistors; and

    said gate electrode of said other input transistor being electrically connected to said output of said amplifier to provide a unity-gain buffer.

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