A method for fabricating a integrated circuit with improved performance is disclosed. The method comprises providing a substrate; performing a plurality of processes to form a gate stack over the substrate, wherein the gate stack comprises a gate layer; measuring a grain size of the gate layer after at least one of the plurality of processes; determining whether the measured grain size is within a target range; and modifying a recipe of at least one of the plurality of processes if the measured grain size of the gate layer is not within the target range.