| 摘要 |
A method for manufacturing a semiconductor device is provided to improve effectively RC delay effect in a peripheral circuit region by forming a gate of a polycide structure on a cell region and forming a gate of a tungsten silicide structure on the peripheral circuit region. A semiconductor substrate(1) including a cell region and a peripheral circuit region is provided. A gate oxide layer(2) is formed on a front surface of the semiconductor substrate. A polysilicon layer(3) is formed on the gate oxide layer. A part of the polysilicon layer formed on the peripheral circuit region is removed selectively. A tungsten silicide layer(5) is deposited on the polysilicon layer of the cell region and the gate oxide layer of the peripheral circuit region. A thermal process is performed to crystallize the tungsten silicide layer. A gate of a polycide structure as a lamination of the polysilicon layer and the tungsten silicide layer is formed on the cell region by etching the tungsten silicide layer, the polysilicon layer, and the gate oxide layer. A tungsten silicide gate as a single layer of the tungsten silicide is formed on the peripheral circuit region.
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