US Patent 11688635 Oxygen-free replacement liner for improved transistor performance

Embodiments of the invention are directed to an integrated circuit. A non-limiting example of the integrated circuit includes a transistor formed over a substrate. A dielectric region is formed over the transistor and the substrate. A trench is positioned in the dielectric region and over a S/D region of the transistor. A first liner and a conductive plug are within the trench such that the first liner and the conductive plug are only present within a bottom portion of the trench. A substantially oxygen-free replacement liner and a S/D contact are within the top portion of the trench such that a bottom contact surface of the S/D contact directly couples to a top surface of the conductive plug.