| 摘要 |
PURPOSE:To improve the reliability of a gate insulating film, to inhibit an impurity diffusion length into a substrate to the utmost and to realize a low contact resistance by a method wherein the natural oxide film of a contact hole is removed in a state that the gate insulating film is protected with a first conductive film and the introduction (an ion-implantation) of a low- concentration impurity is performed. CONSTITUTION:A natural oxide film of a contact part is removed in a state that a gate oxide film 13 is protected with a poly Si film 14. After that, after a second conductive layer, such as a poly Si film 16, is deposited, an ion- implantation is performed using <75>As<+> ions having a comparatively small diffusion coefficient in silicon, but at this time, acceleration is set in such a way that the largest of an ion distribution or the distribution of damage to the oxide film comes to the vicinity of the interface between a substrate 11 and the film 16 in the contact part. Thereby, the reliability of the gate insulating film is improved, an impurity diffusion length into the substrate is inhibited to the utmost and a low contact resistance can be realized.
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