US Patent 8735235 Integrated circuit metal gate structure and method of fabrication

A method is provided for forming a metal gate using a gate last process. A trench is formed on a substrate. The profile of the trench is modified to provide a first width at the aperture of the trench and a second width at the bottom of the trench. The profile may be formed by including tapered sidewalls. A metal gate may be formed in the trench having a modified profile. Also provided is a semiconductor device including a gate structure having a larger width at the top of the gate than the bottom of the gate.