Method and apparatus for reducing threshold voltage mismatch in an integrated circuit

Abstract

A method of making a transistor for an integrated circuit includes providing a substrate and forming a dummy gate for the transistor within a gate trench on the substrate. The gate trench includes sidewalls, a trench bottom, and a trench centerline extending normally from a center portion of the trench bottom. The dummy gate is removed from the gate trench. A gate dielectric layer is disposed within the gate trench. A gate work-function metal layer is disposed over the gate dielectric layer, the work-function metal layer including a pair of corner regions proximate the trench bottom. An angled implantation process is utilized to implant a work-function tuning species into the corner regions at a tilt angle relative to the trench centerline, the tilt angle being greater than zero.