| 摘要 |
A polycide wiring layer constituted by a polysilicon film and a silicide film is used as a bit line of a DRAM. When a memory cell region having an n-type impurity diffusion layer and a peripheral circuit region having a p-type impurity diffusion layer are to be electrically connected through the polysilicon film, a diffusion prevention film consisting of TiSiN or WSiN is formed as an underlying film of the polysilicon film. With this diffusion prevention film, interdiffusion between the n- and p-type impurity diffusion layers can be prevented. In addition, heat resistance at 900 DEG C. or more can be obtained in processes after formation of the diffusion prevention film.
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