| 摘要 |
PURPOSE:To take out an ohmic contact without a breaking of wire from a surface of chip by selectively forming a diffusion preventive film on the substrate contact taking out section and by removing the above film after a source drain layer is formed. CONSTITUTION:A field oxide film 2, a gate oxide film 3, a polycrystalline Si gate electrode 4, a source and drain forming windows 11 and 12, and a substrate contact taking out window 13 are formed on a p-type Si substrate 1. Then a resist layer 14 is selectively formed to the window 13 only in order to obstruct an ion injection, a p-ion is injected and an n-type source and drain layers 5 and 6 are formed. Next, a thin thermal oxide film 15 is formed on the whole surface except the layer 14 and a PSG 8 is laminated. Then an window is selectively opened and an Al wiring 10 is made. By performing this method, an n-layer does not appear on the p-type substrate located below the substrate contact taking out window 13. Therefore, the performance of the polycrystalline Si etching similar to the conventional one is necessary immediately after the window has been opened. Hence a difference in grade is not formed at the window-opened section and a breaking of wire does not occur on the Al wiring, thereby allowing to obtain an excellent ohmic contact. |
