| 摘要 |
PURPOSE:To prevent impurity ions from being diffused to a polycrystal silicon interconnection layer that is connected through a part-process by implanting its impurity ions having a small thermal diffusivity to the silicon layer when a low resistance of the polycrystal silicon is obtained by implanting the impurity ions to its polycrystal silicon. CONSTITUTION:After a gate oxide film 12 and a polycrystal silicon layer 13 are deposited on a silicon semiconductor substrate 11, an arsenic oxide film 14 is deposited on the layer 13 as an impurity ion source having a small thermal diffusivity and this step permits arsenic ions 15 to be thermally diffused in the layer 13. And then, after removing the film 14, the layers 13 and 12 are selectively removed and an interconnection layer is formed by the layer 13 that is left as it is. In this manner the ions 15 are implanted in the layer 13, so that there is no possibility that the ions 15 is diffused in the polycrystal silicon interconnection layer which is connected to the layer 13 through a post- process, when the polycrystal silicon interconnection layer which is connected to the layer 13 through the post-process is heat-treated.
|
