| 摘要 |
PURPOSE: A method for forming a dual gate of a semiconductor device is provided to improve reliability by differently controlling the thickness of gate oxide layers. CONSTITUTION: The first gate oxide pattern(12) and the first undoped polysilicon pattern(13) are sequentially formed on the first region(A) of a substrate(11). The second gate oxide layer(14) is formed on the second region of the substrate and the first undoped polysilicon pattern. The second undoped polysilicon layer(15) is formed on the second gate oxide layer. The second undoped polysilicon layer is selectively removed by using a mask layer spaced apart from the edge portion of the first gate oxide pattern. The first conductive type impurity ions are implanted into the first undoped polysilicon pattern and the second conductive type impurity ions are implanted into the second undoped polysilicon pattern. The first and second gate electrode(16.17) are formed by selectively patterning the first undoped polysilicon pattern and the first gate oxide pattern, and the second undoped polysilicon pattern and the second gate oxide pattern.
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