Burroughs, Inc.

Michael R Gulett

Mark A Vinson

Rakesh Kumar

Norman W Jones

In the disclosed method, dopant atoms of a first conductivity type are implanted into the surface of a semiconductor substrate to form a channel region of each transistor having a relatively high dopant density at a predetermined depth below the surface and a substantially lower dopant density at the surface. This eliminates reachthrough in the channel without adversely increasing the channels threshold voltage. Thereafter, dopant atoms of a second conductivity type are implanted into the substrate to form source and drain regions adjacent to the channels having a depth of less than 0.3 .mu.m below the surface. This minimizes the radius of curvature and corresponding depletion width at the respective junctions with the channel. Subsequently, a patterned insulating layer is formed on said surface at temperatures that are far below the insulating layer's flow point. This avoids diffusing the distribution of the implanted dopant atoms. Later, a layer of metallic contact is formed in an opening of the patterned insulating layer that exposes one of the source and drain regions. This layered metallic contact has a lower layer which is comprised of a material that prevents an upper layer from penetrating through the exposed source or drain region.

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Fort Collins, CO, United States of America

Michael R Gulett