A structure and method for a metal replacement gate of a high performance device
is provided. A sacrificial gate structure is first formed on an etch stop layer
provided on a semiconductor substrate. A pair of spacers is provided on sidewalls
of the sacrificial gate structure. The sacrificial gate structure is then removed,
forming an opening. Subsequently, a metal gate including an first layer of metal
such as tungsten, a diffusion barrier such as titanium nitride, and a second layer
of metal such as tungsten is formed in the opening between the spacers.
