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CMOS imager cell having a buried contact and method of fabrication

  • US 6,291,280 B1
  • Filed: 12/09/1999
  • Issued: 09/18/2001
  • Est. Priority Date: 11/12/1998
  • Status: Expired due to Term
First Claim
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1. A method of forming a buried contact line between a diffusion node and an output transistor in a CMOS imager, comprising:

  • providing a substrate having a first conductivity;

    forming a diffusion region having a second conductivity in said substrate which functions as said diffusion node;

    forming an isolation region in said substrate;

    forming an insulating layer over said substrate, wherein said insulating layer is formed over at least a part of said diffusion region;

    selectively removing at least a portion of said insulating layer to form a diffusion contact area over said diffusion region;

    forming in output transistor on said substrate;

    forming a continuously conductive layer directly on at least a portion of said isolation region to connect said diffusion contact area and a gate of said output transistor, wherein a buried contact between said conductive layer and said diffusion region is formed by diffusion of dopants from said conductive layer into said diffusion region.

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