Metal gate structures and methods for forming thereof are provided herein. In some embodiments, a method for forming a metal gate structure on a substrate having a feature formed in a high k dielectric layer may include depositing a first layer within the feature atop the dielectric layer; depositing a second layer comprising cobalt or nickel within the feature atop the first layer; and depositing a third layer comprising a metal within the feature atop the second layer to fill the feature, wherein at least one of the first or second layers forms a wetting layer to form a nucleation layer for a subsequently deposited layer, wherein one of the first, second, or third layers forms a work function layer, and wherein the third layer forms a gate electrode.