A method of forming dual work function gate electrodes using a doped polysilicon and a metal silicon germanium compound

摘要

A dielectric layer (50) is formed over a semiconductor (10) that contains a first region (20) and a second region (30). A polysilicon layer is formed over the dielectric layer (50) and over the first region (20) and the second region (30). The polysilicon layer can comprise 0 to 50 atomic percent of germanium. A metal layer is formed over the polysilicon layer and one of the regions and reacted with the underlying polysilicon layer to form a metal silicide or a metal germano silicide. The polysilicon and metal silicide or germano silicide regions are etched to form transistor gate regions (60) and (90) respectively. If desired a cladding layer (100) can be formed above the metal gate structures. <IMAGE>