Semiconductor image sensor

  • US 6,023,081 A
  • Filed: 11/14/1997
  • Issued: 02/08/2000
  • Est. Priority Date: 11/14/1997
  • Status: Expired due to Term
First Claim
Patent Images

1. An image sensor comprising:

  • a substrate of a first conductivity type having a first doping concentration;

    an enhancement layer of the first conductivity type having a second doping concentration lower than the first doping concentration, the enhancement layer on the substrate;

    a first MOS transistor on the enhancement layer;

    a first well on the enhancement layer, the first well having the first conductivity type and a third doping concentration that is less than the first doping concentration and greater than the second doping concentration wherein the first MOS transistor is outside the first well; and

    a pinned photodiode on the enhancement layer wherein a portion of the pinned photodiode forms a source of the first MOS transistor.

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