| 摘要 |
Methods of forming field effect transistors according to embodiments of the invention include forming a conductive gate electrode (e.g., polysilicon gate electrode) on a semiconductor substrate and forming a first metal layer on the conductive gate electrode. This first metal layer may include a material selected from a group consisting of nickel, cobalt, titanium, tantalum and tungsten. The first metal layer and the conductive gate electrode are thermally treated for a sufficient duration to convert a first portion of the conductive gate electrode into a first metal silicide region. The first metal layer and the first metal silicide region are then removed to expose a second portion of the conductive gate electrode. A second metal layer is then formed on the second portion of the conductive gate electrode. This second metal layer may include a material selected from a group consisting of nickel, cobalt, titanium, tantalum and tungsten. The second metal layer and the second portion of the conductive gate electrode are thermally treated for a sufficient duration to thereby convert the second portion of the conductive gate electrode into a second metal silicide region.
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