| 摘要 |
PURPOSE:To prevent the unstable tungsten oxide film from being produced by a method wherein a gate electrode comprising tungsten on the surface thereof is formed and after nitrifying the surface of the gate, a channel region is formed below the gate electrode by implanting ions from the surface side. CONSTITUTION:A tungsten gate electrode can be formed by depositing a tungsten film on a substrate, e.g., by sputtering process to be etched into specified pattern by, e.g., reactive ion etching process. The gate electrode is nitrified by heating in oxygen excluded NH3 gas. Later, a channel region is formed below the gate electrode by implanting ion from the gate electrode surface side. That is, the tungsten nitride film on the surface of the formed tungsten gate electrode shields the ion directed during the ion implanting process to prevent the ion-implantation into the channel region from occurring so that the deterioration of the tungsten gate electrode due to the surface oxidation may be prevented from occurring during the formation of an interlayer insulating film and annealing process. |
