A method of making a gate structure includes forming a trench in a dielectric layer. The method further includes forming a gate dielectric layer in the trench. The gate dielectric layer defines an opening in the dielectric layer. The method includes forming a gate electrode in the opening. Forming the gate electrode includes filling a width of a bottom portion of the opening with a first metal material. The first metal material has a recess. Forming the gate electrode includes filling an entire width of a top portion of the opening with a homogeneous second metal material. The homogeneous second metal material has a protrusion extending into the recess, and a maximum width of the homogeneous second metal material is equal to a maximum width of the first metal material. A top surface of the gate dielectric layer is co-planar with a top surface of the homogeneous second metal material.