Low contact resistance and low junction leakage metal interconnect

Abstract

A low contact resistance and low junction leakage metal interconnect contact structure for use with ICs. The contact structure includes an interconnect dielectric material layer on the surface of an IC semiconductor substrate. The interconnect dielectric material layer has a contact opening which extends to a predetermined region of the semiconductor substrate (e.g. a source region, drain region, or polysilicon gate layer). The contact structure also includes a cobalt (or nickel) silicide interface layer on the surface of the predetermined region that is aligned with the bottom of the contact opening, a cobalt (or nickel) adhesion layer on the sidewall surface of the contact opening, a refractory metal-based barrier layer on the metal adhesion layer and the metal silicide interface layer, and a conductive plug. Manufacturing process steps for such a contact structure include first providing a semiconductor substrate with at least one predetermined region (e.g. a drain region, source region or polysilicon gate layer), followed by depositing an interconnect dielectric material layer on the surface of the semiconductor substrate. Contact openings are formed through the interconnect dielectric material layer to expose the predetermined region. A cobalt (or nickel) adhesion layer is then deposited, followed by the deposition of a refractory metal-based barrier layer, and the reaction of cobalt (or nickel) from the adhesion layer with silicon from the exposed predetermined region to form a metal silicide interface layer. Finally, a conductive plug layer is deposited on the barrier layer, filling the contact opening.