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Piezoresistive transducer with low drift output voltage

  • US 5,074,152 A
  • Filed: 12/24/1990
  • Issued: 12/24/1991
  • Est. Priority Date: 12/24/1990
  • Status: Expired due to Term
First Claim
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1. A piezoresistive transducer having an output voltage that has low drift comprises:

  • a lightly doped silicon substrate of a first conductivity type having a flexible silicon diaphragm on a first surface of the substrate;

    a four terminal piezoresistive element of a second conductivity type, the element having two sections which are formed on a second surface of the substrate;

    a first straight section of the piezoresistive element having a contact at each distal end;

    a second straight section of the piezoresistive element having a contact at each distal end wherein the second section is shorter than the first section and has a midpoint that crosses perpendicularly to a midpoint of the first section;

    contact material of the second conductivity type that couples the contacts to metal conductors;

    an irregular periphery formed by the piezoresistive element, the contact material, and the contacts;

    a leakage buffer formed from a continuous strip of highly doped material of the first conductivity type that surrounds the irregular periphery and has material of the first conductivity type projecting from the continuous strip toward the perpendicular crossing;

    a dielectric that covers the second surface of the substrate; and

    a fluorosilicone material that covers the dielectric.

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