| 摘要 |
PURPOSE: A method of forming a gate electrode is to prevent forming of an oxide film on a tungsten surface in a gate electrode having a double structure of polysilicon/tungsten, thereby preventing increasing of a resistance of the gate electrode. CONSTITUTION: A gate oxide film(202) is formed on a semiconductor substrate(200). The gate oxide film is formed by chemical vapor deposition technique. A tungsten layer(206) and a polycrystalline silicon layer(204) are stacked on the gate oxide film in order. The tungsten layer and the polycrystalline silicon layer are patterned to form a gate electrode having a double structure. At this time, a photoresist pattern, in which a gate electrode region is defined, is formed. The tungsten and polycrystalline silicon layer are etching using the photoresist pattern as a mask. The gate oxide film and the remaining polycrystalline silicon are oxidized. The remaining tungsten layer is annealed at hydrogen atmosphere. The annealing process is performed at a temperature of 800 deg.C or more.
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