Self-aligned silicide formation on source/drain through contact via

Abstract

According to certain embodiments, a silicide layer is formed after the fabrication of a functional gate electrode using a gate-last scheme. An initial semiconductor structure has at least one impurity regions formed on a semiconductor substrate, a sacrifice film formed over the impurity region, an isolation layer formed over the sacrifice film and a dielectric layer formed over the isolation film. A via is patterned into the dielectric layer of the initial semiconductor structure and through the thickness of the isolation layer such that a contact opening is formed in the isolation layer. The sacrifice film underlying the isolation layer is then removed leaving a void space underlying the isolation layer. Then, a metal silicide precursor is placed within the void space, and the metal silicide precursor is converted to a silicide layer through an annealing process.