Method of forming dual work function gate electrodes in a semiconductor device

摘要

A method is provided for forming dual work function gate electrodes (90,92). A dielectric layer (30) is provided outwardly of a substrate (20). A metal layer (40) is formed outwardly of the dielectric layer (30). A silicon-germanium layer (50) is formed outwardly of the metal layer (40). A first portion of the silicon-germanium layer (50) is removed to expose a first portion of the metal layer (40), with a second portion of the silicon-germanium layer (50) remaining over a second portion of the metal layer (40). A silicon-germanium metal compound layer (70) is formed from the second portion of the silicon-germanium layer (50) and the second portion of the metal layer (40). A first gate electrode (92) comprising the first portion of the metal layer (40) is formed. A second gate electrode (90) comprising the silicon-germanium metal compound layer (70) is formed.