Patent ID: 8134211

Claim:
A silicon controlled rectifier formed on a substrate comprising: a first well region lightly doped with impurities of a first conductivity type formed on said substrate; a second well region formed within said first well region and lightly doped with impurities of a second conductivity type; a first diffusion region formed within said second well and heavily doped with the impurities of the first conductivity type; a second diffusion region formed within said first well region and heavily doped with impurities of the second conductivity type; a junction between the first well region and the second well region; and a heavily doped polycrystalline layer formed at the surface of said substrate and placed between the first and second diffusion regions and astride the junction of the first well region and the second well region to form a bounding component to prevent silicide formation at junctions of the first diffusion region and the second well region, the first well region and the second region, and the second diffusion region and the first well region during fabrication of said silicon controlled rectifier.