US Patent 9299704 Semiconductor device and method for fabricating the same

A method for fabricating a semiconductor device includes: forming a gate dielectric layer over a substrate; forming an etch stop layer over the gate dielectric layer; forming a first work function layer that covers a first portion of the etch stop layer and a sacrificial compound that covers a second portion of the etch stop layer; exposing the second portion of the etch stop layer by removing the sacrificial compound; and forming a second work function layer over the second portion of the etch stop layer and the first work function layer.