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Low voltage silicon controlled rectifier (SCR) for electrostatic discharge (ESD) protection of silicon-on-insulator technologies

  • US 6,909,149 B2
  • Filed: 04/15/2004
  • Issued: 06/21/2005
  • Est. Priority Date: 04/16/2003
  • Status: Active Grant
First Claim
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1. An electrostatic discharge (ESD) protection circuit in a semiconductor integrated circuit (IC) having protected circuitry, the ESD protection circuit comprising:

  • an SCR for shunting ESD current away from said protected circuitry, said SCR comprising;

    a substrate;

    an N-well and an adjacent P-well formed over said substrate and defining a PN junction therebetween;

    an insulator layer formed over said substrate and electrically isolating said N-well and P-well from said substrate;

    an N+ cathode region formed in said P-well and for coupling to ground;

    a P+ anode region formed in said N-well and for coupling to a pad of said protected circuitry;

    at least one P+ trigger tap region disposed in said P-well and spaced proximate to said N+ cathode region, said at least one P+ trigger tap being adapted to trigger said SCR; and

    at least one N+ trigger tap region disposed in said N-well and spaced proximate to said P+ anode region, said at least one N+ trigger tap being adapted to trigger said SCR.

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